Re: [bolger] tiny "planable" bolger like boat?
Point of reference for speeds. Today I ran for a while behind a 13' aluminum
johnboat with two adults aboard and 6 HP 2-stroke Yamaha on the transom.
According to my GPS, he was making an easy 12-13 mph. I don't know for sure
what that means in the context of this discussion, but I suspect that given
a light enough boat it should be possible to run at least 10 mph up "on
plane" with a 4 HP motor. At any rate, it heartened me for the performance
of my next boat.
johnboat with two adults aboard and 6 HP 2-stroke Yamaha on the transom.
According to my GPS, he was making an easy 12-13 mph. I don't know for sure
what that means in the context of this discussion, but I suspect that given
a light enough boat it should be possible to run at least 10 mph up "on
plane" with a 4 HP motor. At any rate, it heartened me for the performance
of my next boat.
----- Original Message -----
From: <BllFs6@...>
To: <bolger@yahoogroups.com>
Sent: Tuesday, August 16, 2005 9:19 AM
Subject: Re: [bolger] tiny "planable" bolger like boat?
| Hi guys and gals
|
|
| Thanks for all the replies so far...dont really have the time for detailed
| responses right now but again thanks...its got me thinking at least.
|
| One note...the 4 HP motor is rated at 4 hp at 4500 rpm, the gearing ratio
is
| 1.6 roughly, and the prop is a 6 inch diameter with a 6 inch pitch.
|
| Now if we aim for 4000 rpm operation that gives 14mph if I did the math
| right.... and allowing for say 20 percent slip at that speed the motor
would be
| operating at the upper limit of its rpm band. So to my untrained mind the
motor
| doesnt sound to me like its horribly over or under pitched.
|
| I am not a speed demon here.....my speed goal is 8 to 10 mph give or
| take...and I dont HAVE to be planing....the suggestion of an ultra narrow
"canoe"
| with outrigg(ers) that doesnt plan but can slice through the bow wave
with
| modest power sounds good to me...
|
| Does anyone know of an internet source for calculating hull drag as a
| function of speed for narrow hulls? Or a formulae for calculating the hull
speed
| constant as a function of length,beam, draft....?
|
| Or even just a plot that shows drag vs speed curves for a range of narrow
| hulls...so I can get a feel of how narrow is narrow enough?
|
| When I used the inflatable avon last summer....it often "felt" like it was
| on the verge of planing with that motor, but given its floppy nature, its
very
| NON flat floor, and perhaps high drag created by its shape in the transom
| area it wasnt quite happening.
|
| In the middle of the night last night I awoke with an idea.....I could
just
| strap an appropriate shaped piece of plywood to the bottom of the
inflatable
| and I'll have a nearly instant flat bottomed and light weight boat. If I
can
| get it to plane, and get a feel for the physics of it as well as evaluate
how
| I like or dislike relatively slow planing in a small boat, I should be
able
| to scale down slightly and create a workable design.
|
| The inflatable is rated for 700 lbs and the max load required for the new
| boat is more along the lines of 400 to 500 lbs all up. Someone noted that
| planing wasnt gonna happen with 2 people onboard and with 2 the boat would
be a
| slug.....very true...but the avon is a slug anyway so no loss
there....but if
| we can just go "fast" with one on board (which is how the boat is often
used)
| that would be great.
|
| more later..gotta run but thanks again all!
|
| take care
|
| Blll
|
|
| [Non-text portions of this message have been removed]
|
|
|
|
| Bolger rules!!!
| - no cursing, flaming, trolling, spamming, or flogging dead horses
| - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
| - Pls add your comments at the TOP, SIGN your posts, and snip away
| - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
(978) 282-1349
| - Unsubscribe:bolger-unsubscribe@yahoogroups.com
| - Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
| Yahoo! Groups Links
|
|
|
|
|
|
#554 Camping Trimaran has Hobie floats, rig and hardware. Plans
US$100.00 in April 04. Does anyone know about this hull? Length, beam,
cuddy or tent, etc? Is it for sheet ply construction, say like a Piver
Nugget (sans cabin)?
Graeme
--- Inbolger@yahoogroups.com, "Howard Stephenson" <stephensonhw@a...>
wrote:
US$100.00 in April 04. Does anyone know about this hull? Length, beam,
cuddy or tent, etc? Is it for sheet ply construction, say like a Piver
Nugget (sans cabin)?
Graeme
--- Inbolger@yahoogroups.com, "Howard Stephenson" <stephensonhw@a...>
wrote:
> Great minds think alike! I see this idea goes back to 1975.point
>
> Howard
>
> --- Inbolger@yahoogroups.com, "robert pyfrom" <neetra@c...> wrote:
> > Tremolino, anyone?
> > > Every time I see a Hobie Cat I think it could be the starting
> > > for a nice power trimaran, with a simple plywood main hull.
Bruce
When we built the dories a couple of years ago, I had just read an
article in Boat Builder about testing the abrasion resistance of Dynel
compared to fiberglass. One layer of Dynel is about 6 times as tough as
one layer of 6 oz fiberglass and about twice as thick. We have really
rocky/rough beaches here so I went with it. I used blue tape around the
edges and cut to the edge of the tape when it was green for an edge and
then feathered the edge with micro balloons later. The Dynel takes LOTS
of epoxy, three coats to fill if I remember.
The reason I bring this up is the incredible way dynel goes around
corners. It is exceptional for that.
HJ
Bruce Hallman wrote:
When we built the dories a couple of years ago, I had just read an
article in Boat Builder about testing the abrasion resistance of Dynel
compared to fiberglass. One layer of Dynel is about 6 times as tough as
one layer of 6 oz fiberglass and about twice as thick. We have really
rocky/rough beaches here so I went with it. I used blue tape around the
edges and cut to the edge of the tape when it was green for an edge and
then feathered the edge with micro balloons later. The Dynel takes LOTS
of epoxy, three coats to fill if I remember.
The reason I bring this up is the incredible way dynel goes around
corners. It is exceptional for that.
HJ
Bruce Hallman wrote:
>I am shopping for fiberglass for my Topaz Spyder and wonder
>if anybody around here has an opinion on biaxial tape for
>taping chines? Does it drape around the corner?
>
>Also, biaxial 1208 cloth looks interesting and economical
>for glassing the bottom.
>
>
>
>Bolger rules!!!
>- no cursing, flaming, trolling, spamming, or flogging dead horses
>- stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
>- Pls add your comments at the TOP, SIGN your posts, and snip away
>- Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax: (978) 282-1349
>- Unsubscribe:bolger-unsubscribe@yahoogroups.com
>- Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
>Yahoo! Groups Links
>
>
>
>
>
>
>
>
>
>
Great minds think alike! I see this idea goes back to 1975.
Howard
Howard
--- Inbolger@yahoogroups.com, "robert pyfrom" <neetra@c...> wrote:
> Tremolino, anyone?
> > Every time I see a Hobie Cat I think it could be the starting point
> > for a nice power trimaran, with a simple plywood main hull.
Tremolino, anyone?
comboat
comboat
----- Original Message -----
From: "Howard Stephenson" <stephensonhw@...>
To: <bolger@yahoogroups.com>
Sent: Wednesday, August 17, 2005 5:03 PM
Subject: [bolger] Re: tiny "planable" bolger like boat?
> Every time I see a Hobie Cat I think it could be the starting point
> for a nice power trimaran, with a simple plywood main hull.
>
> Howard
>
> --- Inbolger@yahoogroups.com, Lincoln Ross <lincolnr@r...> wrote:
> > Haven't been on this list in quite some time. Not sure I'll be back
> much
> > either. Too many different things to worry about.
> >
> > However, When you mention a 4 hp motor, it makes me wonder how fast
> a
> > Hobie cat would go with a motor?
>
>
>
>
>
>
> Bolger rules!!!
> - no cursing, flaming, trolling, spamming, or flogging dead horses
> - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
> - Pls add your comments at the TOP, SIGN your posts, and snip away
> - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
(978) 282-1349
> - Unsubscribe:bolger-unsubscribe@yahoogroups.com
> - Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
> Yahoo! Groups Links
>
>
>
>
>
>
Every time I see a Hobie Cat I think it could be the starting point
for a nice power trimaran, with a simple plywood main hull.
Howard
for a nice power trimaran, with a simple plywood main hull.
Howard
--- Inbolger@yahoogroups.com, Lincoln Ross <lincolnr@r...> wrote:
> Haven't been on this list in quite some time. Not sure I'll be back
much
> either. Too many different things to worry about.
>
> However, When you mention a 4 hp motor, it makes me wonder how fast
a
> Hobie cat would go with a motor?
Haven't been on this list in quite some time. Not sure I'll be back much
either. Too many different things to worry about.
However, When you mention a 4 hp motor, it makes me wonder how fast a
Hobie cat would go with a motor? Old ones are cheap, and I bet old ones
with busted or missing rigs are cheaper. Of course, I haven't been
following this thread, so I don't know if there are other req'ts that
rule it out. Might be fun. Hobies have a nice soft ride, or at least
the old Hobie 14 did. One advantage is that performance probably won't
degrade too badly with a load.
Lincoln
P.S. I will probably need to get rid of my Brick sometime. Located a bit
west of Boston.
either. Too many different things to worry about.
However, When you mention a 4 hp motor, it makes me wonder how fast a
Hobie cat would go with a motor? Old ones are cheap, and I bet old ones
with busted or missing rigs are cheaper. Of course, I haven't been
following this thread, so I don't know if there are other req'ts that
rule it out. Might be fun. Hobies have a nice soft ride, or at least
the old Hobie 14 did. One advantage is that performance probably won't
degrade too badly with a load.
Lincoln
P.S. I will probably need to get rid of my Brick sometime. Located a bit
west of Boston.
--- Inbolger@yahoogroups.com, Rick Bedard <sctree@y...> wrote:
method?
running feet of that..
Rick --
Glad to hear you can make use of that plastic film technique. I sort
of squandered what I gained, by doing a massy job joining my
beautifully smooth panels. Alas -- next boat . . .
Anyway -- I must've missed an earlier post. What are you building now?
All best,
Garth
> Only have 158 more fillets to go. Ten bulkheads, four edges each,times two faces each, times two hulls... See why my quest for a simple
method?
> Then I'll have to come up with plan B for the internal chines asthey have rocker and the 30 mil plastic won't lay flat.... Only 80
running feet of that..
Rick --
Glad to hear you can make use of that plastic film technique. I sort
of squandered what I gained, by doing a massy job joining my
beautifully smooth panels. Alas -- next boat . . .
Anyway -- I must've missed an earlier post. What are you building now?
All best,
Garth
There have been a couple of Pointy Skiff builders on this board, any
comments about its suitability from them?
comments about its suitability from them?
----- Original Message -----
From: "Howard Stephenson" <stephensonhw@...>
To: <bolger@yahoogroups.com>
Sent: Tuesday, August 16, 2005 9:00 PM
Subject: [bolger] Re: tiny "planable" bolger like boat?
> If you read back through this thread, you will see it's already been
> suggested -- and a few reservations expressed about its suitability.
>
> Howard
>
> --- Inbolger@yahoogroups.com, "Ron Schroeder" <rjs@b...> wrote:
> > How about the Bolger BEE?
The Atkins drew several flat-bottom skiffs that perform well with low power,
and are useful boats for messing about as well. If you're a speed demon,
Scandal is supposed to do 9 mph. with 3 hp. But you have to build Scandal
light to get that kind of performance, and when you take friends along
she'll slow down:
http://www.boat-links.com/Atkinco/Oar/Scandal.html
http://www.boat-links.com/Atkinco/Oar/
and are useful boats for messing about as well. If you're a speed demon,
Scandal is supposed to do 9 mph. with 3 hp. But you have to build Scandal
light to get that kind of performance, and when you take friends along
she'll slow down:
http://www.boat-links.com/Atkinco/Oar/Scandal.html
http://www.boat-links.com/Atkinco/Oar/
On Tue, 16 Aug 2005 09:19:33 EDT, Bill wrote:
> ...
> One note...the 4 HP motor is rated at 4 hp at 4500 rpm, the gearing ratio is
> 1.6 roughly, and the prop is a 6 inch diameter with a 6 inch pitch.
> ...
> I am not a speed demon here.....my speed goal is 8 to 10 mph give or
> take...and I dont HAVE to be planing....the suggestion of an ultra narrow "canoe"
> with outrigg(ers) that doesnt plan but can slice through the bow wave with
> modest power sounds good to me...
> ...
--
John <jkohnen@...>
http://www.boat-links.com/
"Necessity is the mother of invention" is a silly proverb.
"Necessity is the mother of futile dodges" is much nearer the truth.
<Alfred North Whitehead>
I like biaxial tape so much that I now use nothing but.
Outside chines at 3/4" radius are not a problem unless you use too heavy a tape. I'll have to check to see what the weight is that I just used on a Teal. If you need heavy (say for abrasion resistance) you can use two runs of lighter biaxial tape, maybe offset a bit. There is also a biaxial taped stitched to matt (be sure you get the type that is epoxy compatable). The matt really adheres well to plywood and the stiching keeps the biaxial under control. I believe what I have is 17-08 Nytex. Very durable.. I use it mainly for less than 90 degree joins as it so heavy it requires some care to get it down on a hard chine with any rocker.
Inside chines can present a bit of a challange with all the loose threads of biaxial in less than ideal working room. My old strategy was to get 'em later with a grinder, -messy and hard to get the grinder to them). Then I switched to ignoring them until just beyond tacky, use a razor knife to cut them off to a neat edge and add a touch of epoxy w/filler to fair out the sharp edge.. Not bad, but the fillets required sanding and filling to fair them out. (I'm not after a spectacular finish, just an easy to clean corner, but I hate sanding)..
My latest method is glue the bulkheads to the sides without fillets first pass. Next day (you are at clean wood), brush on straight epoxy slightly wider than the fillet area, followed by a fillet putty knifed on of epoxy/wood filler, lay on dry biaxial tape, brush on a cover coat of straight epoxy, then --here's my new part-- lay on a strip of 30 mil plastic, by way of Garth's experiments from ?blank's? use of it, (darn I forgot who first brought the 30 mil stuff up, sorry...). Then use an appropriate shaping device (I use a 3/8" pvc "el" on a stick) aggressively against the plastic to shape the fillet and remove any air bubbles.. Very little mess oozes out.
It may sound like a big production but it's really a quick and simple technique.
I've done a grand total of two fillets each 22" long this way. So far, so good. They come out beautiful, looks like some sort of factory fabricated cove moulding... All tape thread ends imbedded under the skirt of epoxy which naturally feathers out to plywood. Best of all, no follow-up sanding or filling...
Only have 158 more fillets to go. Ten bulkheads, four edges each, times two faces each, times two hulls... See why my quest for a simple method?
Then I'll have to come up with plan B for the internal chines as they have rocker and the 30 mil plastic won't lay flat.... Only 80 running feet of that..
Rick
Bruce Hallman <bruce@...> wrote:
I am shopping for fiberglass for my Topaz Spyder and wonder
if anybody around here has an opinion on biaxial tape for
taping chines? Does it drape around the corner?
Also, biaxial 1208 cloth looks interesting and economical
for glassing the bottom.
Bolger rules!!!
- no cursing, flaming, trolling, spamming, or flogging dead horses
- stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
- Pls add your comments at the TOP, SIGN your posts, and snip away
- Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax: (978) 282-1349
- Unsubscribe:bolger-unsubscribe@yahoogroups.com
- Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
---------------------------------
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[Non-text portions of this message have been removed]
Outside chines at 3/4" radius are not a problem unless you use too heavy a tape. I'll have to check to see what the weight is that I just used on a Teal. If you need heavy (say for abrasion resistance) you can use two runs of lighter biaxial tape, maybe offset a bit. There is also a biaxial taped stitched to matt (be sure you get the type that is epoxy compatable). The matt really adheres well to plywood and the stiching keeps the biaxial under control. I believe what I have is 17-08 Nytex. Very durable.. I use it mainly for less than 90 degree joins as it so heavy it requires some care to get it down on a hard chine with any rocker.
Inside chines can present a bit of a challange with all the loose threads of biaxial in less than ideal working room. My old strategy was to get 'em later with a grinder, -messy and hard to get the grinder to them). Then I switched to ignoring them until just beyond tacky, use a razor knife to cut them off to a neat edge and add a touch of epoxy w/filler to fair out the sharp edge.. Not bad, but the fillets required sanding and filling to fair them out. (I'm not after a spectacular finish, just an easy to clean corner, but I hate sanding)..
My latest method is glue the bulkheads to the sides without fillets first pass. Next day (you are at clean wood), brush on straight epoxy slightly wider than the fillet area, followed by a fillet putty knifed on of epoxy/wood filler, lay on dry biaxial tape, brush on a cover coat of straight epoxy, then --here's my new part-- lay on a strip of 30 mil plastic, by way of Garth's experiments from ?blank's? use of it, (darn I forgot who first brought the 30 mil stuff up, sorry...). Then use an appropriate shaping device (I use a 3/8" pvc "el" on a stick) aggressively against the plastic to shape the fillet and remove any air bubbles.. Very little mess oozes out.
It may sound like a big production but it's really a quick and simple technique.
I've done a grand total of two fillets each 22" long this way. So far, so good. They come out beautiful, looks like some sort of factory fabricated cove moulding... All tape thread ends imbedded under the skirt of epoxy which naturally feathers out to plywood. Best of all, no follow-up sanding or filling...
Only have 158 more fillets to go. Ten bulkheads, four edges each, times two faces each, times two hulls... See why my quest for a simple method?
Then I'll have to come up with plan B for the internal chines as they have rocker and the 30 mil plastic won't lay flat.... Only 80 running feet of that..
Rick
Bruce Hallman <bruce@...> wrote:
I am shopping for fiberglass for my Topaz Spyder and wonder
if anybody around here has an opinion on biaxial tape for
taping chines? Does it drape around the corner?
Also, biaxial 1208 cloth looks interesting and economical
for glassing the bottom.
Bolger rules!!!
- no cursing, flaming, trolling, spamming, or flogging dead horses
- stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
- Pls add your comments at the TOP, SIGN your posts, and snip away
- Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax: (978) 282-1349
- Unsubscribe:bolger-unsubscribe@yahoogroups.com
- Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
---------------------------------
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Visit your group "bolger" on the web.
To unsubscribe from this group, send an email to:
bolger-unsubscribe@yahoogroups.com
Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
---------------------------------
[Non-text portions of this message have been removed]
My own experience is that it doesn't work well for taping chines, but perhaps
there is a different technique to use. I always apply cloth, whether glass,
polypro, dynal, etc by squeegee. Works great on everything else, but the
biaxial tape unraveled and made a big mess to sand off, whereas reg. tape comes
out smooth.
Bob
[Non-text portions of this message have been removed]
there is a different technique to use. I always apply cloth, whether glass,
polypro, dynal, etc by squeegee. Works great on everything else, but the
biaxial tape unraveled and made a big mess to sand off, whereas reg. tape comes
out smooth.
Bob
[Non-text portions of this message have been removed]
If you read back through this thread, you will see it's already been
suggested -- and a few reservations expressed about its suitability.
Howard
suggested -- and a few reservations expressed about its suitability.
Howard
--- Inbolger@yahoogroups.com, "Ron Schroeder" <rjs@b...> wrote:
> How about the Bolger BEE?
Hi Bill,
Another idea might be a 15 foot by 2 1/2 or 3 foot beam version of the
Sneakeasy if you can handle the extra length. That should easily go over 8
kts.
I have a 9.5' inflatable with an 8HP. It's fast and fun but it just pounds
in any chop at all.
Ron
Another idea might be a 15 foot by 2 1/2 or 3 foot beam version of the
Sneakeasy if you can handle the extra length. That should easily go over 8
kts.
I have a 9.5' inflatable with an 8HP. It's fast and fun but it just pounds
in any chop at all.
Ron
----- Original Message -----
From: <BllFs6@...>
To: <bolger@yahoogroups.com>
Sent: Monday, August 15, 2005 10:04 AM
Subject: [bolger] tiny "planable" bolger like boat?
> Hi all
>
> I have access to 4 HP 2 stroke motor...used it on a friends inflatable
Avon
> (like a Zodiac) 9 footer last summer. It was a blast cruising around all
day
> and only burning a few gallons. And as an aside for anyone who has never
used
> a small inflatable, you must try one sometime...you just might be suprised
> at how fun they are....and being able to put your boat and motor in a car
trunk
> sure can be handy at times.
>
> Anyway....the Avon was a blast....but 4 knots max was a bit slower than
I'd
> like, though I could live with it fairly happily if I had to.
>
> My question is, is there a design for a light, small one person boat that
> will go more like 8 to 12 knots, most likely planing, on a measely 4 hp?
This
> boat would also preferably be pretty short, 9 feet give or take. Or maybe
a
> semi-displacement hull design that allows me to push hull speed up to 8 or
so
> knots?
>
> If there really isnt such a design, any interest in designing one?
>
> take care
>
> Blll
I'm often wrong. On reflection, I think the truth is somewhere in
between yours and my view. Michalak himself says that you'd need 5
hp to plane it, on that same page. However, judging by the waveform
it's not "hardly moving", but it isn't fully on the plane either.
Note how the peak of the stern wave seems to be well aft of the hull.
The trim could be wrong too, although the
According to plans, at 410lb displacement the waterline would be 4"
above the bottom, in level trim. As shown, my guess is that there is
no more than 300 lb. So if we define planing as a state where more
than half the boat's weight is supported dynamically rather than by
buoyancy, the hull would be planing once it rises less than 2" out
of the water -- something rather difficult to judge from a photo.
Howard
between yours and my view. Michalak himself says that you'd need 5
hp to plane it, on that same page. However, judging by the waveform
it's not "hardly moving", but it isn't fully on the plane either.
Note how the peak of the stern wave seems to be well aft of the hull.
The trim could be wrong too, although the
According to plans, at 410lb displacement the waterline would be 4"
above the bottom, in level trim. As shown, my guess is that there is
no more than 300 lb. So if we define planing as a state where more
than half the boat's weight is supported dynamically rather than by
buoyancy, the hull would be planing once it rises less than 2" out
of the water -- something rather difficult to judge from a photo.
Howard
--- Inbolger@yahoogroups.com, James Greene <jg6892@g...> wrote:
> > Someone's already suggested the QT skiff. Here's a picture of
one that
> > to me looks like it's planing with only 2-1/2 horsepower.
> >
> >http://www.duckworksbbs.com/plans/jim/qt_skiff/
>
>
> To me it looks like it's hardly moving, not planing, and the
reason the
> bow is so high is because of that weight in the rear. Then again,
I've
> been wrong before ... :)
Bruce, I think it is Sam Devlin who recommends biaxial
tape for high-stress areas. There are three ways to
incorporate expert opinion in building a boat: 1) get
and consider it beforehand--good 2) don't bother to
get it at all (also sometimes good) 3) get it after or
towards the end of a project, too late to use it, and
then fret about it (bad). My Topaz construction fits
the last category. I knew nothing about building
large boats tack-and-tape until I read Devlin, which
would have been a good idea before building my Topaz,
but not so good with the hull complete. I put a layer
of biaxial tape on the inside of the sole/side panel
joints, in the places I could reach--the bottom was
already painted. The tape took the inside angle and
the curve of the hull without problem. It is coarse,
and hard to fill smoothly with resin. Whether it
added any strength, I don't know--I have not had any
joint failure anywhere on the boat in several years of
hard use, including a couple of thousand miles of
bouncing on the trailer. Sam
--- Bruce Hallman <bruce@...> wrote:
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
tape for high-stress areas. There are three ways to
incorporate expert opinion in building a boat: 1) get
and consider it beforehand--good 2) don't bother to
get it at all (also sometimes good) 3) get it after or
towards the end of a project, too late to use it, and
then fret about it (bad). My Topaz construction fits
the last category. I knew nothing about building
large boats tack-and-tape until I read Devlin, which
would have been a good idea before building my Topaz,
but not so good with the hull complete. I put a layer
of biaxial tape on the inside of the sole/side panel
joints, in the places I could reach--the bottom was
already painted. The tape took the inside angle and
the curve of the hull without problem. It is coarse,
and hard to fill smoothly with resin. Whether it
added any strength, I don't know--I have not had any
joint failure anywhere on the boat in several years of
hard use, including a couple of thousand miles of
bouncing on the trailer. Sam
--- Bruce Hallman <bruce@...> wrote:
> I am shopping for fiberglass for my Topaz Spyder and__________________________________________________
> wonder
> if anybody around here has an opinion on biaxial
> tape for
> taping chines? Does it drape around the corner?
>
> Also, biaxial 1208 cloth looks interesting and
> economical
> for glassing the bottom.
>
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Send me your address off list and I'll put a piece in the mail for you to
play with.
email to john dot m dot bell at earthlink dot net.
Best,
JB
play with.
email to john dot m dot bell at earthlink dot net.
Best,
JB
----- Original Message -----
From: "Bruce Hallman" <bruce@...>
To: <bolger@yahoogroups.com>
Sent: Tuesday, August 16, 2005 3:06 PM
Subject: Re: [bolger] biaxial tape
| > It needs a fairly large radius to work well on
| > outside seams,
| > JB
|
| By 'fairly large radius' do you mean, say, 3/4 inch?
|
|
|
| Bolger rules!!!
| - no cursing, flaming, trolling, spamming, or flogging dead horses
| - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
| - Pls add your comments at the TOP, SIGN your posts, and snip away
| - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
(978) 282-1349
| - Unsubscribe:bolger-unsubscribe@yahoogroups.com
| - Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
| Yahoo! Groups Links
|
|
|
|
|
|
|
Depending on cloth weight, 3/4" radius should be OK.
----- Original Message -----
From: "Bruce Hallman" <bruce@...>
To: <bolger@yahoogroups.com>
Sent: Tuesday, August 16, 2005 3:06 PM
Subject: Re: [bolger] biaxial tape
| > It needs a fairly large radius to work well on
| > outside seams,
| > JB
|
| By 'fairly large radius' do you mean, say, 3/4 inch?
|
|
|
| Bolger rules!!!
| - no cursing, flaming, trolling, spamming, or flogging dead horses
| - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
| - Pls add your comments at the TOP, SIGN your posts, and snip away
| - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
(978) 282-1349
| - Unsubscribe:bolger-unsubscribe@yahoogroups.com
| - Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
| Yahoo! Groups Links
|
|
|
|
|
|
|
> It needs a fairly large radius to work well onBy 'fairly large radius' do you mean, say, 3/4 inch?
> outside seams,
> JB
It's great on inside fillets. It needs a fairly large radius to work well on
outside seams, but is otherwise OK. I used 9oz. extensively on two boats and
would use it again.
JB
outside seams, but is otherwise OK. I used 9oz. extensively on two boats and
would use it again.
JB
----- Original Message -----
From: "Bruce Hallman" <bruce@...>
To: <bolger@yahoogroups.com>
Sent: Tuesday, August 16, 2005 2:34 PM
Subject: [bolger] biaxial tape
| I am shopping for fiberglass for my Topaz Spyder and wonder
| if anybody around here has an opinion on biaxial tape for
| taping chines? Does it drape around the corner?
|
| Also, biaxial 1208 cloth looks interesting and economical
| for glassing the bottom.
|
|
|
| Bolger rules!!!
| - no cursing, flaming, trolling, spamming, or flogging dead horses
| - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
| - Pls add your comments at the TOP, SIGN your posts, and snip away
| - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
(978) 282-1349
| - Unsubscribe:bolger-unsubscribe@yahoogroups.com
| - Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
| Yahoo! Groups Links
|
|
|
|
|
|
|
I am shopping for fiberglass for my Topaz Spyder and wonder
if anybody around here has an opinion on biaxial tape for
taping chines? Does it drape around the corner?
Also, biaxial 1208 cloth looks interesting and economical
for glassing the bottom.
if anybody around here has an opinion on biaxial tape for
taping chines? Does it drape around the corner?
Also, biaxial 1208 cloth looks interesting and economical
for glassing the bottom.
Good suggestion Howard. Note that Jim says it *may* plane with a 5 hp
motor if the driver were light enough.
Since we're in the neighborhood, why not look at Jon Jr.?
http://www.duckworksbbs.com/plans/jim/jon_jr/index.htm
Build it taped seams style and opt out for 5.2 mm Ultraply and you
should be able to get the weight down to close to the QT Skiff.
With the weight reduction and Jon Jr's wider transom she'd probably do
better than the QT Skiff on plane.
Another, and IMHO, a better choice for choppier conditions would be
Twanghttp://www.duckworksbbs.com/plans/jim/twang/index.htm
Just some thoughts.
Bryant
--- Inbolger@yahoogroups.com, "Howard Stephenson" <stephensonhw@a...>
wrote:
motor if the driver were light enough.
Since we're in the neighborhood, why not look at Jon Jr.?
http://www.duckworksbbs.com/plans/jim/jon_jr/index.htm
Build it taped seams style and opt out for 5.2 mm Ultraply and you
should be able to get the weight down to close to the QT Skiff.
With the weight reduction and Jon Jr's wider transom she'd probably do
better than the QT Skiff on plane.
Another, and IMHO, a better choice for choppier conditions would be
Twanghttp://www.duckworksbbs.com/plans/jim/twang/index.htm
Just some thoughts.
Bryant
--- Inbolger@yahoogroups.com, "Howard Stephenson" <stephensonhw@a...>
wrote:
> Someone's already suggested the QT skiff. Here's a picture of one that
> to me looks like it's planing with only 2-1/2 horsepower.
>
>http://www.duckworksbbs.com/plans/jim/qt_skiff/
>
> Howard
Hi guys and gals
Thanks for all the replies so far...dont really have the time for detailed
responses right now but again thanks...its got me thinking at least.
One note...the 4 HP motor is rated at 4 hp at 4500 rpm, the gearing ratio is
1.6 roughly, and the prop is a 6 inch diameter with a 6 inch pitch.
Now if we aim for 4000 rpm operation that gives 14mph if I did the math
right.... and allowing for say 20 percent slip at that speed the motor would be
operating at the upper limit of its rpm band. So to my untrained mind the motor
doesnt sound to me like its horribly over or under pitched.
I am not a speed demon here.....my speed goal is 8 to 10 mph give or
take...and I dont HAVE to be planing....the suggestion of an ultra narrow "canoe"
with outrigg(ers) that doesnt plan but can slice through the bow wave with
modest power sounds good to me...
Does anyone know of an internet source for calculating hull drag as a
function of speed for narrow hulls? Or a formulae for calculating the hull speed
constant as a function of length,beam, draft....?
Or even just a plot that shows drag vs speed curves for a range of narrow
hulls...so I can get a feel of how narrow is narrow enough?
When I used the inflatable avon last summer....it often "felt" like it was
on the verge of planing with that motor, but given its floppy nature, its very
NON flat floor, and perhaps high drag created by its shape in the transom
area it wasnt quite happening.
In the middle of the night last night I awoke with an idea.....I could just
strap an appropriate shaped piece of plywood to the bottom of the inflatable
and I'll have a nearly instant flat bottomed and light weight boat. If I can
get it to plane, and get a feel for the physics of it as well as evaluate how
I like or dislike relatively slow planing in a small boat, I should be able
to scale down slightly and create a workable design.
The inflatable is rated for 700 lbs and the max load required for the new
boat is more along the lines of 400 to 500 lbs all up. Someone noted that
planing wasnt gonna happen with 2 people onboard and with 2 the boat would be a
slug.....very true...but the avon is a slug anyway so no loss there....but if
we can just go "fast" with one on board (which is how the boat is often used)
that would be great.
more later..gotta run but thanks again all!
take care
Blll
[Non-text portions of this message have been removed]
Thanks for all the replies so far...dont really have the time for detailed
responses right now but again thanks...its got me thinking at least.
One note...the 4 HP motor is rated at 4 hp at 4500 rpm, the gearing ratio is
1.6 roughly, and the prop is a 6 inch diameter with a 6 inch pitch.
Now if we aim for 4000 rpm operation that gives 14mph if I did the math
right.... and allowing for say 20 percent slip at that speed the motor would be
operating at the upper limit of its rpm band. So to my untrained mind the motor
doesnt sound to me like its horribly over or under pitched.
I am not a speed demon here.....my speed goal is 8 to 10 mph give or
take...and I dont HAVE to be planing....the suggestion of an ultra narrow "canoe"
with outrigg(ers) that doesnt plan but can slice through the bow wave with
modest power sounds good to me...
Does anyone know of an internet source for calculating hull drag as a
function of speed for narrow hulls? Or a formulae for calculating the hull speed
constant as a function of length,beam, draft....?
Or even just a plot that shows drag vs speed curves for a range of narrow
hulls...so I can get a feel of how narrow is narrow enough?
When I used the inflatable avon last summer....it often "felt" like it was
on the verge of planing with that motor, but given its floppy nature, its very
NON flat floor, and perhaps high drag created by its shape in the transom
area it wasnt quite happening.
In the middle of the night last night I awoke with an idea.....I could just
strap an appropriate shaped piece of plywood to the bottom of the inflatable
and I'll have a nearly instant flat bottomed and light weight boat. If I can
get it to plane, and get a feel for the physics of it as well as evaluate how
I like or dislike relatively slow planing in a small boat, I should be able
to scale down slightly and create a workable design.
The inflatable is rated for 700 lbs and the max load required for the new
boat is more along the lines of 400 to 500 lbs all up. Someone noted that
planing wasnt gonna happen with 2 people onboard and with 2 the boat would be a
slug.....very true...but the avon is a slug anyway so no loss there....but if
we can just go "fast" with one on board (which is how the boat is often used)
that would be great.
more later..gotta run but thanks again all!
take care
Blll
[Non-text portions of this message have been removed]
> Someone's already suggested the QT skiff. Here's a picture of one thatTo me it looks like it's hardly moving, not planing, and the reason the
> to me looks like it's planing with only 2-1/2 horsepower.
>
>http://www.duckworksbbs.com/plans/jim/qt_skiff/
bow is so high is because of that weight in the rear. Then again, I've
been wrong before ... :)
James Greene
Someone's already suggested the QT skiff. Here's a picture of one that
to me looks like it's planing with only 2-1/2 horsepower.
http://www.duckworksbbs.com/plans/jim/qt_skiff/
Howard
to me looks like it's planing with only 2-1/2 horsepower.
http://www.duckworksbbs.com/plans/jim/qt_skiff/
Howard
--- Inbolger@yahoogroups.com, "John Bell" <smallboatdesigner@m...>
wrote:
prototype, not a boat meant to do more than prove the box keel
concept that has proven very successful in Microtrawler, Hawkeye,
and Retriever.
There is also a pic around of a 10' or so "super Bee" perhaps
adapted from Bee plans, that looks to be a very servicable boat,
like the Bolger plans designs.
If one would build a Bee, perhaps higher sides are a good idea.
Don
wrote:
> I've seen on this list criticism of BEE that it was a not a verytransition
> satisfactory boat in actual practice. It was badly behaved in the
> between planing and displacement modes, particularly on slowingdown where
> the stern wave would roll over the transom thus swamping the boat.It was
> also too low sided to be very seaworthy.It is important to remember Bee was a proof of concept 1/2 scale
prototype, not a boat meant to do more than prove the box keel
concept that has proven very successful in Microtrawler, Hawkeye,
and Retriever.
There is also a pic around of a 10' or so "super Bee" perhaps
adapted from Bee plans, that looks to be a very servicable boat,
like the Bolger plans designs.
If one would build a Bee, perhaps higher sides are a good idea.
Don
You might check out "poor Man's Whaler on HH Payson's site.
John T
John T
----- Original Message -----
From: "Bruce Hallman" <bruce@...>
To: <bolger@yahoogroups.com>
Sent: Monday, August 15, 2005 10:36 AM
Subject: Re: [bolger] tiny "planable" bolger like boat?
> > My question is, is there a design for a light, small one person boat
that
> > will go more like 8 to 12 knots, most likely planing, on a measely 4 hp?
> > Blll
>
> I think the Bolger Bee probably would work.
>
>http://hallman.org/bolger/381/bee.gif
>
> Fax or mail your question to Bolger, who sells the plans.
>
> Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax: (978)
282-1349
>
>
>
> Bolger rules!!!
> - no cursing, flaming, trolling, spamming, or flogging dead horses
> - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
> - Pls add your comments at the TOP, SIGN your posts, and snip away
> - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
(978) 282-1349
> - Unsubscribe:bolger-unsubscribe@yahoogroups.com
> - Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
> --
> Internal Virus Database is out-of-date.
> Checked by AVG Anti-Virus.
> Version: 7.0.338 / Virus Database: 267.9.6/59 - Release Date: 7/27/2005
>
>
In a message dated 8/15/05 10:50:38 AM Central Daylight Time,
willsamson@...writes:
interested in these topics.
"Displacement speed" is simply the maximum speed that a boat will go without
"planing", so it is sort of a tautology. The formula Gerr gives for maximum
"displacement" speed is S/L = 8.26/(D/L)^0.311. Under this scheme S/L=1 when
speed in Kts. is equal to the square root of the waterline length in feet, i.e.
for a 16 ft. hull, 4 Kts. = S/L of 1, aka "hull speed". There is nothing
magical about 1.5 X "hull speed". In fact, few conventional powerboats are light
enough to do that well in a non-planing mode. Gerr has a chart showing maximum
displacement speeds up to S/L = 3.2 for boats of a very, very low, possibly
unobtainable, D/L ratio of 20 (D/L= Displacement in Long Tons (2,240
lb.)/(0.01*LWL)^3). (He indicates that D/l ratios of 60-100 are "extremely light")
The formula he gives for planing (Crouch's Formula) is a whole different
animal. It gives the maximum speed as Kts = C/Displacement in lbs./SHP)^0.5. "C"
is an empirical constant ranging from 150 (ordinary planing craft) to 230
(racing power catamarans and sea sleds). (Interestingly enough, 3-point hydros only
rate 220 - perhaps because of aerodynamic lift that catamarans and sea sleds
enjoy?)
Plotting these formulae on a common x-y plot gives two curves as different as
apples and oranges. The speed ranges given by the two formula (given a long
enough and light enough boat with a high enough hp/lb ratio) partially overlap.
In the range of the overlap, the formulae give differing values for power
required for a given speed. Plotting these curves on Lotus 1-2-3 or an equivalent
program is a harmless divertissement that I find kind of entertaining.
It is understandable that no one has devoted much attention at the minimum
speed a boat can "plane" at. Gerr does not hazard any description of what
"planing" consists of, but I will hazard that it is when wave drag becomes an
insignificant factor and skin and appendage drag predominate. At what speed a boat
capable of making the transition from one state to the other does so, and what
happens in the intermediate state of "semi-displacement" function, would seem
to be subjects of some mystery and probably very dependent among the details
of hull shape, a factor only obliquely incorporated in the two formulae.
Ciao for Niao,
Bill in MN
[Non-text portions of this message have been removed]
willsamson@...writes:
> I'm sure there must be some equations that help describe this phenomenon.I heartily commend David Gerr's "Propellor Handbook" to anyone who is
> If I recall right, the displacement speed (kts) is one and a half times the
> square root of the waterline length (feet).
interested in these topics.
"Displacement speed" is simply the maximum speed that a boat will go without
"planing", so it is sort of a tautology. The formula Gerr gives for maximum
"displacement" speed is S/L = 8.26/(D/L)^0.311. Under this scheme S/L=1 when
speed in Kts. is equal to the square root of the waterline length in feet, i.e.
for a 16 ft. hull, 4 Kts. = S/L of 1, aka "hull speed". There is nothing
magical about 1.5 X "hull speed". In fact, few conventional powerboats are light
enough to do that well in a non-planing mode. Gerr has a chart showing maximum
displacement speeds up to S/L = 3.2 for boats of a very, very low, possibly
unobtainable, D/L ratio of 20 (D/L= Displacement in Long Tons (2,240
lb.)/(0.01*LWL)^3). (He indicates that D/l ratios of 60-100 are "extremely light")
The formula he gives for planing (Crouch's Formula) is a whole different
animal. It gives the maximum speed as Kts = C/Displacement in lbs./SHP)^0.5. "C"
is an empirical constant ranging from 150 (ordinary planing craft) to 230
(racing power catamarans and sea sleds). (Interestingly enough, 3-point hydros only
rate 220 - perhaps because of aerodynamic lift that catamarans and sea sleds
enjoy?)
Plotting these formulae on a common x-y plot gives two curves as different as
apples and oranges. The speed ranges given by the two formula (given a long
enough and light enough boat with a high enough hp/lb ratio) partially overlap.
In the range of the overlap, the formulae give differing values for power
required for a given speed. Plotting these curves on Lotus 1-2-3 or an equivalent
program is a harmless divertissement that I find kind of entertaining.
It is understandable that no one has devoted much attention at the minimum
speed a boat can "plane" at. Gerr does not hazard any description of what
"planing" consists of, but I will hazard that it is when wave drag becomes an
insignificant factor and skin and appendage drag predominate. At what speed a boat
capable of making the transition from one state to the other does so, and what
happens in the intermediate state of "semi-displacement" function, would seem
to be subjects of some mystery and probably very dependent among the details
of hull shape, a factor only obliquely incorporated in the two formulae.
Ciao for Niao,
Bill in MN
[Non-text portions of this message have been removed]
In a message dated 8/15/05 10:25:36 AM Central Daylight Time,
bruce@...writes:
small hp. It will give more lifting surface and less wetted area than a step
sharpie and also weigh less. Planing speed is largely a function of hp. v.
weight, and weight is certainly a function of length and surface area. I think
getting a boat with only 4 hp. to plane an adult would present a challenge. For one
thing, would the propellor's pitch be high enough to reach the projected
speed? If not, are higher pitch props available? If the propellor is pitched for 4
mph at max rpms, you'll need to double the pitch to go 8 mph. You won't be
able to get that much of an increase in pitch using the Robb White
hammer-and-block-of-wood technique of propellor adjustment!
A more practical choice might be some kind of square-sterned canoe - a
flat-bottomed pirogue would be the best candidate if one hoped to plane. I doubt if
one could be made to plane with 4 hp., but it would at a minimum give some
multiple of "hull speed", assuming adequate propellor pitch, and performance
would be less degraded by addition of a passenger, while a short planing boat that
wouldn't plane would be a really ugly slug. To work in this fashion, a canoe
would have to be much longer than 9' - probably 16' minimum to have decent
stability, but it would be cartoppable.
I think the recommendation to look at what Glen-L has available for small
planing designs is a good suggestion. When I was a lad, a friend of my had a
class-something-or-another "racing runabout" - a relic of the 50's when racing
those things was the vogue in the MidWest. (Class rules prohibited steps, but
other than that the boats made few concessions to being "runabouts" as we
commonly thought of them.) I was envious of my pal, and spend many hours
contemplating Glen-L's offerings, all of which were beyond my means. If memory serves, I
believe that there was a design called "TNT" or the like that was pretty
similar to my friend's boat. There were also small three-point hydros and "skimmers"
to contemplate. "Skimmers" were kind of a primitive precursor to PWC's -
basically just a sheet of plywood shaped like a short fat toboggan with enough
flotation for a boy and a small motor perched on a sort of a vertical erection in
lieu of a transom. The best that could be said for them was that they were
probably more practical than the hydros, for any purpose other than racing, and
much easier to build. My friend's boat was pretty capable in comparison.
My friend's boat was about 12' long, had about 6" or 8" of freeboard with
sides flared forward and tumblehomed aft. The floor was flat and it was decked
over with two "cockpits" formed by openings in the deck. There was "shark-fin"
shaped aluminum fin about 6" deep set amidships in the bottom of the hull.
Construction was 1/4" ply on very light and minimal framing. It was powered by a
10 hp green-tank Mercury motor. The motor had a special "Quicksilver" lower
unit with a very short shaft and an above the water exhaust. The propellor about
3" in diameter and 6" long of Lord only know what pitch. It looked more like
the impeller from a taffrail log than any propellor I've ever seen before or
since. The driver knelt on a boat cushion lying directly on the bottom of the
boat in the rear of two "cockpits". With one 100-120 lb. boy operating the thing
it was something of a screamer. With two such boys, getting it up on a plane
required some gymnastics and speed was much reduced, but it still planed.
I don't know if the power plant had been modified, but stock "green-tank" 10
hp. Mercs were notoriously underrated - either as a marketing ploy or because
their quality control was so bad, or the former to make a virtue out of the
latter. In any case, a good "green-tank" was commonly felt to crank out
something closer to 12 hp than to 10 hp, and perhaps even more. I had the use of a 3
hp Johnson at the time. It never occurred to us to see what it would do on my
friend's boat, but I very much doubt if it would have sufficed to get even one
100 lb boy up onto a plane. It did develop enough power and speed to cause a
conventional 17' aluminum canoe to "squat" for lack of adequate bearing aft as
it exceeded hull speed .
The boat could handle mild chop on inland lakes - but only for a short time.
We never ran it much in those conditions as it always developed an ignition
fault and conked out under those conditions. The fault would go away after a
while of not running. We boys could not figure out where the problem lay and I
suspect my friend's father probably thought it was a fine safety feature, as he
certainly never indicated the least bit of interest in sorting it out himself!
Ciao for Niao,
Bill in MN
[Non-text portions of this message have been removed]
bruce@...writes:
> Given, a 'pretty short' constraint, a step sharpie hull givesI think that a flat bottomed boat would give the best chance of planing on
> a small motor a better chance to achieve plane.
small hp. It will give more lifting surface and less wetted area than a step
sharpie and also weigh less. Planing speed is largely a function of hp. v.
weight, and weight is certainly a function of length and surface area. I think
getting a boat with only 4 hp. to plane an adult would present a challenge. For one
thing, would the propellor's pitch be high enough to reach the projected
speed? If not, are higher pitch props available? If the propellor is pitched for 4
mph at max rpms, you'll need to double the pitch to go 8 mph. You won't be
able to get that much of an increase in pitch using the Robb White
hammer-and-block-of-wood technique of propellor adjustment!
A more practical choice might be some kind of square-sterned canoe - a
flat-bottomed pirogue would be the best candidate if one hoped to plane. I doubt if
one could be made to plane with 4 hp., but it would at a minimum give some
multiple of "hull speed", assuming adequate propellor pitch, and performance
would be less degraded by addition of a passenger, while a short planing boat that
wouldn't plane would be a really ugly slug. To work in this fashion, a canoe
would have to be much longer than 9' - probably 16' minimum to have decent
stability, but it would be cartoppable.
I think the recommendation to look at what Glen-L has available for small
planing designs is a good suggestion. When I was a lad, a friend of my had a
class-something-or-another "racing runabout" - a relic of the 50's when racing
those things was the vogue in the MidWest. (Class rules prohibited steps, but
other than that the boats made few concessions to being "runabouts" as we
commonly thought of them.) I was envious of my pal, and spend many hours
contemplating Glen-L's offerings, all of which were beyond my means. If memory serves, I
believe that there was a design called "TNT" or the like that was pretty
similar to my friend's boat. There were also small three-point hydros and "skimmers"
to contemplate. "Skimmers" were kind of a primitive precursor to PWC's -
basically just a sheet of plywood shaped like a short fat toboggan with enough
flotation for a boy and a small motor perched on a sort of a vertical erection in
lieu of a transom. The best that could be said for them was that they were
probably more practical than the hydros, for any purpose other than racing, and
much easier to build. My friend's boat was pretty capable in comparison.
My friend's boat was about 12' long, had about 6" or 8" of freeboard with
sides flared forward and tumblehomed aft. The floor was flat and it was decked
over with two "cockpits" formed by openings in the deck. There was "shark-fin"
shaped aluminum fin about 6" deep set amidships in the bottom of the hull.
Construction was 1/4" ply on very light and minimal framing. It was powered by a
10 hp green-tank Mercury motor. The motor had a special "Quicksilver" lower
unit with a very short shaft and an above the water exhaust. The propellor about
3" in diameter and 6" long of Lord only know what pitch. It looked more like
the impeller from a taffrail log than any propellor I've ever seen before or
since. The driver knelt on a boat cushion lying directly on the bottom of the
boat in the rear of two "cockpits". With one 100-120 lb. boy operating the thing
it was something of a screamer. With two such boys, getting it up on a plane
required some gymnastics and speed was much reduced, but it still planed.
I don't know if the power plant had been modified, but stock "green-tank" 10
hp. Mercs were notoriously underrated - either as a marketing ploy or because
their quality control was so bad, or the former to make a virtue out of the
latter. In any case, a good "green-tank" was commonly felt to crank out
something closer to 12 hp than to 10 hp, and perhaps even more. I had the use of a 3
hp Johnson at the time. It never occurred to us to see what it would do on my
friend's boat, but I very much doubt if it would have sufficed to get even one
100 lb boy up onto a plane. It did develop enough power and speed to cause a
conventional 17' aluminum canoe to "squat" for lack of adequate bearing aft as
it exceeded hull speed .
The boat could handle mild chop on inland lakes - but only for a short time.
We never ran it much in those conditions as it always developed an ignition
fault and conked out under those conditions. The fault would go away after a
while of not running. We boys could not figure out where the problem lay and I
suspect my friend's father probably thought it was a fine safety feature, as he
certainly never indicated the least bit of interest in sorting it out himself!
Ciao for Niao,
Bill in MN
[Non-text portions of this message have been removed]
In the same book there is Dugout, 11'9" x 3', with a broad transom
stern. Bolger says it "would go along nicely with anything from 2 to 5
h.p." The catch is that it's meant to be constructed from "lifts",
lateral rather than vertical ones, made of lumber of varying
dimensions, 1-1/2" square being the smallest. There is a table of
offsets, so it might be feasible to cold-mold or strip-plank the shape
but, according to Bolger, molding would be a lot more work than
building from lifts.
It's most likely never been built and is not really a complete design
as presented in the book. To my eye it has a lovely shape.
Howard
stern. Bolger says it "would go along nicely with anything from 2 to 5
h.p." The catch is that it's meant to be constructed from "lifts",
lateral rather than vertical ones, made of lumber of varying
dimensions, 1-1/2" square being the smallest. There is a table of
offsets, so it might be feasible to cold-mold or strip-plank the shape
but, according to Bolger, molding would be a lot more work than
building from lifts.
It's most likely never been built and is not really a complete design
as presented in the book. To my eye it has a lovely shape.
Howard
--- Inbolger@yahoogroups.com, "Nels" <arvent@h...> wrote:
> There is also the motor canoe in Chapter 14 of BWAOM
Maybe it's worthwhile introducing the hull to a termite colony ...
Howard
Howard
--- Inbolger@yahoogroups.com, James Greene <jg6892@g...> wrote:
> it's a relatively heavy 21 foot boat to begin with since it has a
half
> hollowed out log for a keel/bottom (and I stupidly covered the hull
> with fiberglass and too much poly resin thinking that it needed the
> extra strength and durability -- which it does not).
--- Inbolger@yahoogroups.com, BllFs6@a... wrote:
availabble from Dynamite Payson. Both are cartoppabl/back of pickup
truck or van.
Cartopper is also an excellent design.
Nels
> Hi allboat that
> My question is, is there a design for a light, small one person
> will go more like 8 to 12 knots, most likely planing, on a measely4 hp? This
> boat would also preferably be pretty short, 9 feet give or take.Or maybe a
> semi-displacement hull design that allows me to push hull speed upto 8 or so
> knots?There is also the motor canoe in Chapter 14 of BWAOM and Skimmer
>
> If there really isnt such a design, any interest in designing one?
>
> take care
>
> Blll
>
availabble from Dynamite Payson. Both are cartoppabl/back of pickup
truck or van.
Cartopper is also an excellent design.
Nels
> My question is, is there a design for a light, small one person boatYes, most of the small Philippine bankas would do this easily. They
> that
> will go more like 8 to 12 knots, most likely planing, on a measely 4
> hp?
are not bolger boats and they do not plane, but they would actually go
faster -- probably 15-20 knots.
> This boat would also preferably be pretty short, 9 feet give or take.Go for a 10/1 length beam ratio at the waterline, or 12/1 if you can
manage it. With a super-slim hull and amas for stability you will
never have to worry about capsizing, and the narrow hull will allow the
boat to go really fast on very little horsepower -- without climbing on
top of the water to achieve this speed like planing hull would have to.
These boats slice through the water like a knife, never trying to get
on plane. My banka goes 20+ knots on 8 hp with two people in it, and
it's a relatively heavy 21 foot boat to begin with since it has a half
hollowed out log for a keel/bottom (and I stupidly covered the hull
with fiberglass and too much poly resin thinking that it needed the
extra strength and durability -- which it does not).
If you make one that's lightweight and no more than a foot wide but 12
feet long (or longer) at the waterline you would "haul ass" using only
4 hp!
James Greene
There probably are... just not me!
The guy who really seems to know about such things is Julian Bethwaite,
designer of really fast sailing skiffs like the 49er. He has embraced the
concept that if you don't have a big 'hump" (bow wave, or energy barrier) to
get over to transition from displacement to planing that it's easier to get
the boat on plane.
I can't think of anyone who's doing the same kind of work on powerboats,
though. The keys seem to be light weight, light bottom loadings, proper
weight distribution, and a hull shape that limits wave making.
I think Robb's boat would be a pretty good way to put your 3.5 motor back on
the water:http://www.robbwhite.com/sportboat.html
The guy who really seems to know about such things is Julian Bethwaite,
designer of really fast sailing skiffs like the 49er. He has embraced the
concept that if you don't have a big 'hump" (bow wave, or energy barrier) to
get over to transition from displacement to planing that it's easier to get
the boat on plane.
I can't think of anyone who's doing the same kind of work on powerboats,
though. The keys seem to be light weight, light bottom loadings, proper
weight distribution, and a hull shape that limits wave making.
I think Robb's boat would be a pretty good way to put your 3.5 motor back on
the water:http://www.robbwhite.com/sportboat.html
----- Original Message -----
From: "Will Samson" <willsamson@...>
To: <bolger@yahoogroups.com>
Sent: Monday, August 15, 2005 11:49 AM
Subject: Re: [bolger] tiny "planable" bolger like boat?
> >>Robb White talks about the best boats for low power being ones that are
> planing before they go faster than displacment speed. >>
>
> I'm sure there must be some equations that help describe this phenomenon.
If I recall right, the displacement speed (kts) is one and a half times the
square root of the waterline length (feet). Is there something similar to
tell you the speed at which a boat gets up on the plane?
>
> I've got a brand new 3.5hp two-stroke OB and would be interested in
finding a design for a small boat that would do well with that power.
Whether it planes or not doesn't greatly bother me - I just don't want it to
lift its nose in the air and bury its transom when I open the throttle.
Elegant progress is the thing.
>
> Bill
>
> [Non-text portions of this message have been removed]
>
>
>
>
> Bolger rules!!!
> - no cursing, flaming, trolling, spamming, or flogging dead horses
> - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
> - Pls add your comments at the TOP, SIGN your posts, and snip away
> - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
(978) 282-1349
> - Unsubscribe:bolger-unsubscribe@yahoogroups.com
> - Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
> Yahoo! Groups Links
>
>
>
>
>
>
>
On 8/15/05, John Bell wrote:
Here are quotes from what he wrote:
"The Bee I built on a lark, overbuilt it (which was a HUGE mistake),
never had the correct outboard for it, and never had a use for it, so
it was eventulyy cut up...
Rick"
"I built a Bee way back when the plans were first released. The plans
cost me $5. so you can imagine how long ago it was. I made the great
mistake of using odd bits of scrap ply I had on hand, some as thick as
1/2" and also glassed inside and out, so had a hull way, way too
heavy, probably 40 or 50 pounds more than designed. With that weight,
plus me, my 4 hp would almost get the boat up on plane, but not quite.
Very stable hull, and a good rowboat in windy conditions with the box
keel and the low freeboard.. Everyone who saw it commented on the low
freeboard. Almost sunk it once by sitting too close to an aft corner.
No one ever offered to try it with a bigger outboard....
I have photos somewhere I'll post if I find them.
Rick"
> Someone had built one and cut it up after discovering that it was not veryThat was Rick Bedard, he is around here so he might chime in.
> good.
Here are quotes from what he wrote:
"The Bee I built on a lark, overbuilt it (which was a HUGE mistake),
never had the correct outboard for it, and never had a use for it, so
it was eventulyy cut up...
Rick"
"I built a Bee way back when the plans were first released. The plans
cost me $5. so you can imagine how long ago it was. I made the great
mistake of using odd bits of scrap ply I had on hand, some as thick as
1/2" and also glassed inside and out, so had a hull way, way too
heavy, probably 40 or 50 pounds more than designed. With that weight,
plus me, my 4 hp would almost get the boat up on plane, but not quite.
Very stable hull, and a good rowboat in windy conditions with the box
keel and the low freeboard.. Everyone who saw it commented on the low
freeboard. Almost sunk it once by sitting too close to an aft corner.
No one ever offered to try it with a bigger outboard....
I have photos somewhere I'll post if I find them.
Rick"
I'd take anything Bernie said about boats he sold plans for with a grain of
salt. <chuckle> His old CSD catalog was prone to a bit of hyperbole. (And
for the ultimate stretch of credulity, see the deathless prose describing
FLYAWAY. lol!)
Anyway, I don't recall who said becuase it was at least three years ago.
Someone had built one and cut it up after discovering that it was not very
good. Let's just say there is a reason that the guy in your photo of BEE is
sitting so far forward with the gas tank in the bow. It's really a *small*
boat for its size!
For my part, short and long don't really mean anything with regards to
whether a boat is large or small. I took the orignal poster's question to
mean a small boat that will plane with low power. IMO, planing speeds in
really short boats is too dangerous in anything but perfectly flat water,
and even then I'm still not so sure it's a good idea.
salt. <chuckle> His old CSD catalog was prone to a bit of hyperbole. (And
for the ultimate stretch of credulity, see the deathless prose describing
FLYAWAY. lol!)
Anyway, I don't recall who said becuase it was at least three years ago.
Someone had built one and cut it up after discovering that it was not very
good. Let's just say there is a reason that the guy in your photo of BEE is
sitting so far forward with the gas tank in the bow. It's really a *small*
boat for its size!
For my part, short and long don't really mean anything with regards to
whether a boat is large or small. I took the orignal poster's question to
mean a small boat that will plane with low power. IMO, planing speeds in
really short boats is too dangerous in anything but perfectly flat water,
and even then I'm still not so sure it's a good idea.
----- Original Message -----
From: "Bruce Hallman" <bruce@...>
To: <bolger@yahoogroups.com>
Sent: Monday, August 15, 2005 11:25 AM
Subject: Re: [bolger] tiny "planable" bolger like boat?
> On 8/15/05, John Bell wrote:
>
> > I stand by my original statement that long and lean would be better.
>
> Of course, making almost any boat longer will make it better,
> but Bill was asking about a 'pretty short' boat.
>
> Given, a 'pretty short' constraint, a step sharpie hull gives
> a small motor a better chance to achieve plane.
>
> > It was badly behaved in the transition
> > between planing and displacement modes,
> > particularly on slowing down where
> > the stern wave would roll over the transom
> > thus swamping the boat.
>
> I am curious where you heard this; I just re-read the
> Bee thread from December, 2004 and it wasn't
> mentioned back then.
>
> DonB did report that if the boat is intended for
> use as a tender that PCB recommends raising
> the sides a few inches.
>
> The only 'first hand' report of Bee that I am aware
> of is the description by Bernie Wolfard, which
> doesn't mention a 'transition problem" coming
> off of plane.
>
>
>
> Bolger rules!!!
> - no cursing, flaming, trolling, spamming, or flogging dead horses
> - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
> - Pls add your comments at the TOP, SIGN your posts, and snip away
> - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
(978) 282-1349
> - Unsubscribe:bolger-unsubscribe@yahoogroups.com
> - Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
> Yahoo! Groups Links
>
>
>
>
>
>
>
>>Robb White talks about the best boats for low power being ones that areplaning before they go faster than displacment speed. >>
I'm sure there must be some equations that help describe this phenomenon. If I recall right, the displacement speed (kts) is one and a half times the square root of the waterline length (feet). Is there something similar to tell you the speed at which a boat gets up on the plane?
I've got a brand new 3.5hp two-stroke OB and would be interested in finding a design for a small boat that would do well with that power. Whether it planes or not doesn't greatly bother me - I just don't want it to lift its nose in the air and bury its transom when I open the throttle. Elegant progress is the thing.
Bill
[Non-text portions of this message have been removed]
On 8/15/05, John Bell wrote:
but Bill was asking about a 'pretty short' boat.
Given, a 'pretty short' constraint, a step sharpie hull gives
a small motor a better chance to achieve plane.
Bee thread from December, 2004 and it wasn't
mentioned back then.
DonB did report that if the boat is intended for
use as a tender that PCB recommends raising
the sides a few inches.
The only 'first hand' report of Bee that I am aware
of is the description by Bernie Wolfard, which
doesn't mention a 'transition problem" coming
off of plane.
> I stand by my original statement that long and lean would be better.Of course, making almost any boat longer will make it better,
but Bill was asking about a 'pretty short' boat.
Given, a 'pretty short' constraint, a step sharpie hull gives
a small motor a better chance to achieve plane.
> It was badly behaved in the transitionI am curious where you heard this; I just re-read the
> between planing and displacement modes,
> particularly on slowing down where
> the stern wave would roll over the transom
> thus swamping the boat.
Bee thread from December, 2004 and it wasn't
mentioned back then.
DonB did report that if the boat is intended for
use as a tender that PCB recommends raising
the sides a few inches.
The only 'first hand' report of Bee that I am aware
of is the description by Bernie Wolfard, which
doesn't mention a 'transition problem" coming
off of plane.
I've seen on this list criticism of BEE that it was a not a very
satisfactory boat in actual practice. It was badly behaved in the transition
between planing and displacement modes, particularly on slowing down where
the stern wave would roll over the transom thus swamping the boat. It was
also too low sided to be very seaworthy. Stretched out to 12 feet on the
same beam and a little higher sided it might be acceptable, but even then
I'm not sure what question it answers.
I stand by my original statement that long and lean would be better.
satisfactory boat in actual practice. It was badly behaved in the transition
between planing and displacement modes, particularly on slowing down where
the stern wave would roll over the transom thus swamping the boat. It was
also too low sided to be very seaworthy. Stretched out to 12 feet on the
same beam and a little higher sided it might be acceptable, but even then
I'm not sure what question it answers.
I stand by my original statement that long and lean would be better.
----- Original Message -----
From: "Bruce Hallman" <bruce@...>
To: <bolger@yahoogroups.com>
Sent: Monday, August 15, 2005 10:51 AM
Subject: Re: [bolger] tiny "planable" bolger like boat?
> On 8/15/05, John Bell wrote:
> > A long, lean, and light boat would be better than a short one for
planing.
>
> Of course, shorter means lighter, usually.
>
> The step, of the 'step sharpie', on the Bee gives a
> long [really, slender] shape for the boat to plane upon.
>
>http://hallman.org/bolger/381/CSDbee.gif
>
>
>
> Bolger rules!!!
> - no cursing, flaming, trolling, spamming, or flogging dead horses
> - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
> - Pls add your comments at the TOP, SIGN your posts, and snip away
> - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
(978) 282-1349
> - Unsubscribe:bolger-unsubscribe@yahoogroups.com
> - Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
> Yahoo! Groups Links
>
>
>
>
>
>
>
On 8/15/05, John Bell wrote:
The step, of the 'step sharpie', on the Bee gives a
long [really, slender] shape for the boat to plane upon.
http://hallman.org/bolger/381/CSDbee.gif
> A long, lean, and light boat would be better than a short one for planing.Of course, shorter means lighter, usually.
The step, of the 'step sharpie', on the Bee gives a
long [really, slender] shape for the boat to plane upon.
http://hallman.org/bolger/381/CSDbee.gif
A long, lean, and light boat would be better than a short one for planing.
The worst point for a planing boat is the transition between displacement
and planing modes. A short boat makes a big hole in the water that it won't
get out of unless it has enough power. FWIW, a 9-footer at 8 knots would be
fully on plane (S/L = 2.6)
Robb White talks about the best boats for low power being ones that are
planing before they go faster than displacment speed. I'm getting started on
Robb's "Sport Boat" as my next project. This is a 15' strip planked motor
canoe that is reputed to go 12-14 mph on 5 HP.
For a simpler version, Jim Michalak's QT skiff (the motor version) might be
a good choice provided you built it lightly.
The worst point for a planing boat is the transition between displacement
and planing modes. A short boat makes a big hole in the water that it won't
get out of unless it has enough power. FWIW, a 9-footer at 8 knots would be
fully on plane (S/L = 2.6)
Robb White talks about the best boats for low power being ones that are
planing before they go faster than displacment speed. I'm getting started on
Robb's "Sport Boat" as my next project. This is a 15' strip planked motor
canoe that is reputed to go 12-14 mph on 5 HP.
For a simpler version, Jim Michalak's QT skiff (the motor version) might be
a good choice provided you built it lightly.
----- Original Message -----
From: <BllFs6@...>
To: <bolger@yahoogroups.com>
Sent: Monday, August 15, 2005 10:04 AM
Subject: [bolger] tiny "planable" bolger like boat?
> Hi all
>
> I have access to 4 HP 2 stroke motor...used it on a friends inflatable
Avon
> (like a Zodiac) 9 footer last summer. It was a blast cruising around all
day
> and only burning a few gallons. And as an aside for anyone who has never
used
> a small inflatable, you must try one sometime...you just might be suprised
> at how fun they are....and being able to put your boat and motor in a car
trunk
> sure can be handy at times.
>
> Anyway....the Avon was a blast....but 4 knots max was a bit slower than
I'd
> like, though I could live with it fairly happily if I had to.
>
> My question is, is there a design for a light, small one person boat that
> will go more like 8 to 12 knots, most likely planing, on a measely 4 hp?
This
> boat would also preferably be pretty short, 9 feet give or take. Or maybe
a
> semi-displacement hull design that allows me to push hull speed up to 8 or
so
> knots?
>
> If there really isnt such a design, any interest in designing one?
>
> take care
>
> Blll
>
>
> [Non-text portions of this message have been removed]
>
>
>
>
> Bolger rules!!!
> - no cursing, flaming, trolling, spamming, or flogging dead horses
> - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
> - Pls add your comments at the TOP, SIGN your posts, and snip away
> - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
(978) 282-1349
> - Unsubscribe:bolger-unsubscribe@yahoogroups.com
> - Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
> Yahoo! Groups Links
>
>
>
>
>
>
>
> My question is, is there a design for a light, small one person boat thatI think the Bolger Bee probably would work.
> will go more like 8 to 12 knots, most likely planing, on a measely 4 hp?
> Blll
http://hallman.org/bolger/381/bee.gif
Fax or mail your question to Bolger, who sells the plans.
Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax: (978) 282-1349
Bill, you might look at the Glen-L site. They have
(or had in the fabled days of my youth) a number of
designs for one-main hydroplanes designed for very low
horseposer. Sam
---BllFs6@...wrote:
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
(or had in the fabled days of my youth) a number of
designs for one-main hydroplanes designed for very low
horseposer. Sam
---BllFs6@...wrote:
> Hi all__________________________________________________
>
> I have access to 4 HP 2 stroke motor...used it on a
> friends inflatable Avon
> (like a Zodiac) 9 footer last summer. It was a blast
> cruising around all day
> and only burning a few gallons. And as an aside for
> anyone who has never used
> a small inflatable, you must try one sometime...you
> just might be suprised
> at how fun they are....and being able to put your
> boat and motor in a car trunk
> sure can be handy at times.
>
> Anyway....the Avon was a blast....but 4 knots max
> was a bit slower than I'd
> like, though I could live with it fairly happily if
> I had to.
>
> My question is, is there a design for a light, small
> one person boat that
> will go more like 8 to 12 knots, most likely
> planing, on a measely 4 hp? This
> boat would also preferably be pretty short, 9 feet
> give or take. Or maybe a
> semi-displacement hull design that allows me to push
> hull speed up to 8 or so
> knots?
>
> If there really isnt such a design, any interest in
> designing one?
>
> take care
>
> Blll
>
>
> [Non-text portions of this message have been
> removed]
>
>
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Hi all
I have access to 4 HP 2 stroke motor...used it on a friends inflatable Avon
(like a Zodiac) 9 footer last summer. It was a blast cruising around all day
and only burning a few gallons. And as an aside for anyone who has never used
a small inflatable, you must try one sometime...you just might be suprised
at how fun they are....and being able to put your boat and motor in a car trunk
sure can be handy at times.
Anyway....the Avon was a blast....but 4 knots max was a bit slower than I'd
like, though I could live with it fairly happily if I had to.
My question is, is there a design for a light, small one person boat that
will go more like 8 to 12 knots, most likely planing, on a measely 4 hp? This
boat would also preferably be pretty short, 9 feet give or take. Or maybe a
semi-displacement hull design that allows me to push hull speed up to 8 or so
knots?
If there really isnt such a design, any interest in designing one?
take care
Blll
[Non-text portions of this message have been removed]
I have access to 4 HP 2 stroke motor...used it on a friends inflatable Avon
(like a Zodiac) 9 footer last summer. It was a blast cruising around all day
and only burning a few gallons. And as an aside for anyone who has never used
a small inflatable, you must try one sometime...you just might be suprised
at how fun they are....and being able to put your boat and motor in a car trunk
sure can be handy at times.
Anyway....the Avon was a blast....but 4 knots max was a bit slower than I'd
like, though I could live with it fairly happily if I had to.
My question is, is there a design for a light, small one person boat that
will go more like 8 to 12 knots, most likely planing, on a measely 4 hp? This
boat would also preferably be pretty short, 9 feet give or take. Or maybe a
semi-displacement hull design that allows me to push hull speed up to 8 or so
knots?
If there really isnt such a design, any interest in designing one?
take care
Blll
[Non-text portions of this message have been removed]