Birdwatcher
There was comment here a while ago about Ian and Robyn's boat. Here's the AABB article:
http://www.boatbuilder.com.au/images/stories/mag/dawnsong.pdf
Graeme
http://www.boatbuilder.com.au/images/stories/mag/dawnsong.pdf
Graeme
I'm sure some one else may have seen and posted this link.
It says they'll build you a Birdwatcher I or II for $12,000 to $15,000.
http://www.adirondackgoodboat.com/boatbuilding.html
Jeff
[Non-text portions of this message have been removed]
It says they'll build you a Birdwatcher I or II for $12,000 to $15,000.
http://www.adirondackgoodboat.com/boatbuilding.html
Jeff
[Non-text portions of this message have been removed]
China cloud had twin keels and a lee board also.
http://www.virtualmuseum.ca/pm.php?id=story_line&fl=&lg=English&ex=00000113&sl=1446&pos=15
HJ
http://www.virtualmuseum.ca/pm.php?id=story_line&fl=&lg=English&ex=00000113&sl=1446&pos=15
HJ
>Yes, I've read the various articles on the new BW.
>
>I'm now recalling where I saw twin bilge keels on a junk rigged boat, I
>believe it was on one of Alan Farrell's, perhaps even China Cloud itself.
>Very handy for places where you are going to have to cope with anchorages
>what do dry out. I believe there are a couple Laurent Giles designs with
>the same.
>
>
>
>"we've given the new boat a long, steel-ballested centerboard forYes, I've read the various articles on the new BW.
>more sail-carrying capacity and increased lateral resistance in deep
>water and shallow."
I'm now recalling where I saw twin bilge keels on a junk rigged boat, I
believe it was on one of Alan Farrell's, perhaps even China Cloud itself.
Very handy for places where you are going to have to cope with anchorages
what do dry out. I believe there are a couple Laurent Giles designs with
the same.
The complaint about jammed 'centreplates' seems to have emanated mainly
from England where the beaches and harbors often have a rocky or pebbly
bottom.
\
Anyway, a Birdwatcher style boat with twin keels would probably be no worse
than many daysailers. If it were my modification project, I'd make 'em as
simple as possible and live with the compromises. My point was that PCB has
done many a simple plate fin keel in his day.
But it's not my mod, so .... (My mod was making a 1.5 inch thick bottom).
--
Craig O'Donnell
Sinepuxent Ancestors & Boats
<http://freepages.genealogy.rootsweb.com/~fassitt/>
The Proa FAQ <http://boat-links.com/proafaq.html>
The Cheap Pages <http://www.friend.ly.net/~dadadata/>
Sailing Canoes, Polytarp Sails, Bamboo, Chinese Junks,
American Proas, the Bolger Boat Honor Roll,
Plywood Boats, Bamboo Rafts, &c.
_________________________________
-- Professor of Boatology -- Junkomologist
-- Macintosh kinda guy
Friend of Wanda the Wonder Cat, 1991-1997.
_________________________________
... and probably not real fast to windward, compared with a cat with
proper daggerboards.
Howard
--- Inbolger@yahoogroups.com, "pvanderwaart" <pvanderwaart@y...>
wrote:
proper daggerboards.
Howard
--- Inbolger@yahoogroups.com, "pvanderwaart" <pvanderwaart@y...>
wrote:
> > I think Bolger would caution about putting a fancy set o' keelskeels
> > on what is essentially a cheap and simple hull.
>
> Well, Thomas Firth Jones used sections of 2x10 (or similar) for
> on his Weekender Catamaran. Not real fancy.
>
>http://www.jonesboats.com/Images/weekendplan.jpg
>
> Peter
| So if you don't want those benefits, then try something else. Seems
| strange how people rave about a design then decide they want to
| modify it:-)
Exactly! Of course if you are truly crazy like me, you'll try your hand at
designing your own from scratch. It's harder than it looks. But it's also
its own reward.
| strange how people rave about a design then decide they want to
| modify it:-)
Exactly! Of course if you are truly crazy like me, you'll try your hand at
designing your own from scratch. It's harder than it looks. But it's also
its own reward.
--- Inbolger@yahoogroups.com, craig o'donnell <dadadata@f...> wrote:
"we've given the new boat a long, steel-ballested centerboard for
more sail-carrying capacity and increased lateral resistance in deep
water and shallow."
So if you don't want those benefits, then try something else. Seems
strange how people rave about a design then decide they want to
modify it:-)
Cheers, Nels
>what is
> I think Bolger would caution about putting a fancy set o' keels on
> essentially a cheap and simple hull.Here is what the article states:
> --
>
"we've given the new boat a long, steel-ballested centerboard for
more sail-carrying capacity and increased lateral resistance in deep
water and shallow."
So if you don't want those benefits, then try something else. Seems
strange how people rave about a design then decide they want to
modify it:-)
Cheers, Nels
> I think Bolger would caution about putting a fancy set o' keelsWell, Thomas Firth Jones used sections of 2x10 (or similar) for keels
> on what is essentially a cheap and simple hull.
on his Weekender Catamaran. Not real fancy.
http://www.jonesboats.com/Images/weekendplan.jpg
Peter
I think Bolger would caution about putting a fancy set o' keels on what is
essentially a cheap and simple hull.
--
Craig O'Donnell
Sinepuxent Ancestors & Boats
<http://freepages.genealogy.rootsweb.com/~fassitt/>
The Proa FAQ <http://boat-links.com/proafaq.html>
The Cheap Pages <http://www.friend.ly.net/~dadadata/>
Sailing Canoes, Polytarp Sails, Bamboo, Chinese Junks,
American Proas, the Bolger Boat Honor Roll,
Plywood Boats, Bamboo Rafts, &c.
_________________________________
-- Professor of Boatology -- Junkomologist
-- Macintosh kinda guy
Friend of Wanda the Wonder Cat, 1991-1997.
_________________________________
essentially a cheap and simple hull.
--
Craig O'Donnell
Sinepuxent Ancestors & Boats
<http://freepages.genealogy.rootsweb.com/~fassitt/>
The Proa FAQ <http://boat-links.com/proafaq.html>
The Cheap Pages <http://www.friend.ly.net/~dadadata/>
Sailing Canoes, Polytarp Sails, Bamboo, Chinese Junks,
American Proas, the Bolger Boat Honor Roll,
Plywood Boats, Bamboo Rafts, &c.
_________________________________
-- Professor of Boatology -- Junkomologist
-- Macintosh kinda guy
Friend of Wanda the Wonder Cat, 1991-1997.
_________________________________
I think, because we don't usually make stuff like fixed, fancy foils,
that we overestimate the difficulty. Just hot-wire a foam core and glass
over it. If you use dense foam and enough glass, it ought to be plenty
strong! It can be something like 12% or even 15% thick without too much
penalty. For hot wiring you really only need two auto batteries, some
.020" music wire, alligator clips, some copper wire, two templates, and
a slightly flexible bow. The bow could be made from scrap wood, and the
templates from aluminum, pc board material, nice quality plywood, etc.
You do need two people to make the cuts. If someone wants to try
something like this, I could cut the core for a small fee if the
shipping problem could be solved.
that we overestimate the difficulty. Just hot-wire a foam core and glass
over it. If you use dense foam and enough glass, it ought to be plenty
strong! It can be something like 12% or even 15% thick without too much
penalty. For hot wiring you really only need two auto batteries, some
.020" music wire, alligator clips, some copper wire, two templates, and
a slightly flexible bow. The bow could be made from scrap wood, and the
templates from aluminum, pc board material, nice quality plywood, etc.
You do need two people to make the cuts. If someone wants to try
something like this, I could cut the core for a small fee if the
shipping problem could be solved.
>Message: 5snip
> Date: Thu, 23 Sep 2004 13:40:01 -0000
> From: "ghartc" <ghartc@...>
>Subject: Re: Birdwatcher
>
>I think you're going exactly the wrong way - if you live in deep
>water, why the 4" draft? The best foils are very long (deep) and very
>skinny - high aspect. This is what allows you to sail upwind.
>Bolger's boards are modestly proportioned only because they can be
>built slab-sided of plywood. Fancy foils are hard to make one-off as
>they need to be carefully shaped and high-strength.
>
>
If you don't need shallow draft, you ought to approximate the shape of
the supplied board. Aspect ratio matters, that's why you don't see
airliners with wings that are 5 feet wide down the whole length of the
plane. It would be much easier from a structural point of view but it
just wouldn't work very well. I suppose if you don't need much upwind
ability....
the supplied board. Aspect ratio matters, that's why you don't see
airliners with wings that are 5 feet wide down the whole length of the
plane. It would be much easier from a structural point of view but it
just wouldn't work very well. I suppose if you don't need much upwind
ability....
>"daveydimwit" <david@...>
>Subject: Birdwatcher
>
>I keep looking at my information on the Birdwatcher and the more I
>look, the more it like it except -
>Where I live the water is deep and I hate centerboards. The only thing
>I hate more are leeboards.
>I was wondering what would happen if I replace the centerboard with
>twin keels. To be more accurate, I guess they would be twin skegs.
>To get the same area I figure that about 15 feet long by 4 inches deep
>would more than do it.
>I would do twin so when the boat heeled, one would always be in the
>water.
>Any ideas?
>
I think you're going exactly the wrong way - if you live in deep
water, why the 4" draft? The best foils are very long (deep) and very
skinny - high aspect. This is what allows you to sail upwind.
Bolger's boards are modestly proportioned only because they can be
built slab-sided of plywood. Fancy foils are hard to make one-off as
they need to be carefully shaped and high-strength.
Anyway, if you plan to sail reasonably well, your bilgeboards need to
be as deep as possible, almost as much as a shoal-type (e.g. wing)
keel. If you look at where these devices are used, you'll only seee
them in shoals or in drying out in big tides. Like all shoal-draft
solutions, they compromise sailing.
I agree with you aesthetically about leeboards, but I wonder what your
objection to centerboards are? Even deep water comes to an edge
somewhere, and I see the Birdwatcher as a good beachcomber. If you
have a keel or bilgeboards, that gets in the way and makes trailering
difficult.
Gregg Carlson
water, why the 4" draft? The best foils are very long (deep) and very
skinny - high aspect. This is what allows you to sail upwind.
Bolger's boards are modestly proportioned only because they can be
built slab-sided of plywood. Fancy foils are hard to make one-off as
they need to be carefully shaped and high-strength.
Anyway, if you plan to sail reasonably well, your bilgeboards need to
be as deep as possible, almost as much as a shoal-type (e.g. wing)
keel. If you look at where these devices are used, you'll only seee
them in shoals or in drying out in big tides. Like all shoal-draft
solutions, they compromise sailing.
I agree with you aesthetically about leeboards, but I wonder what your
objection to centerboards are? Even deep water comes to an edge
somewhere, and I see the Birdwatcher as a good beachcomber. If you
have a keel or bilgeboards, that gets in the way and makes trailering
difficult.
Gregg Carlson
--- Inbolger@yahoogroups.com, "daveydimwit" <david@c...> wrote:
> I keep looking at my information on the Birdwatcher and the more I
> look, the more it like it except -
> Where I live the water is deep and I hate centerboards. The only thing
> I hate more are leeboards.
> I was wondering what would happen if I replace the centerboard with
> twin keels. To be more accurate, I guess they would be twin skegs.
> To get the same area I figure that about 15 feet long by 4 inches deep
> would more than do it.
> I would do twin so when the boat heeled, one would always be in the
> water.
> Any ideas?
Without comment on the cb v bilge keels debate, PBS has a program Called The Boat Shop with tapes of various shows available (www.theboatshop.com). Show #512 includes a 5 minute segment on a Birdwatcher; PB&F says they'll have a video available this fall.
jOHN t
jOHN t
----- Original Message -----
From: daveydimwit
To:bolger@yahoogroups.com
Sent: Wednesday, September 22, 2004 7:18 PM
Subject: [bolger] Birdwatcher
I keep looking at my information on the Birdwatcher and the more I
look, the more it like it except -
Where I live the water is deep and I hate centerboards. The only thing
I hate more are leeboards.
I was wondering what would happen if I replace the centerboard with
twin keels. To be more accurate, I guess they would be twin skegs.
To get the same area I figure that about 15 feet long by 4 inches deep
would more than do it.
I would do twin so when the boat heeled, one would always be in the
water.
Any ideas?
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
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[Non-text portions of this message have been removed]
--- Inbolger@yahoogroups.com, "daveydimwit" <david@c...> wrote:
plane. However the hull has to have considerable ballest to get it
deep enough for them to be effective.
Perhaps one could build the BWll to specs and leave the centerboard
case empty and closed over. That way the centerboard could be added
later. But just realize that it is a part of the seaworthiness
capabalilty of the boat and I am quite certain PCB&F would not
approve. BWII is a superior design as now is drawn.
Cheers, Nels
> I keep looking at my information on the Birdwatcher and the more Ithing
> look, the more it like it except -
> Where I live the water is deep and I hate centerboards. The only
> I hate more are leeboards.deep
> I was wondering what would happen if I replace the centerboard with
> twin keels. To be more accurate, I guess they would be twin skegs.
> To get the same area I figure that about 15 feet long by 4 inches
> would more than do it.Are you familar with PARADOX? It uses chine runners for lateral
> I would do twin so when the boat heeled, one would always be in the
> water.
> Any ideas?
plane. However the hull has to have considerable ballest to get it
deep enough for them to be effective.
Perhaps one could build the BWll to specs and leave the centerboard
case empty and closed over. That way the centerboard could be added
later. But just realize that it is a part of the seaworthiness
capabalilty of the boat and I am quite certain PCB&F would not
approve. BWII is a superior design as now is drawn.
Cheers, Nels
I keep looking at my information on the Birdwatcher and the more I
look, the more it like it except -
Where I live the water is deep and I hate centerboards. The only thing
I hate more are leeboards.
I was wondering what would happen if I replace the centerboard with
twin keels. To be more accurate, I guess they would be twin skegs.
To get the same area I figure that about 15 feet long by 4 inches deep
would more than do it.
I would do twin so when the boat heeled, one would always be in the
water.
Any ideas?
look, the more it like it except -
Where I live the water is deep and I hate centerboards. The only thing
I hate more are leeboards.
I was wondering what would happen if I replace the centerboard with
twin keels. To be more accurate, I guess they would be twin skegs.
To get the same area I figure that about 15 feet long by 4 inches deep
would more than do it.
I would do twin so when the boat heeled, one would always be in the
water.
Any ideas?
>...what happens when it rains?The Birdwatcher II seems to be drawn with hard slot covers.
Asking PB&F this question would be a good idea.
I built and sail a Michalak design that is based on a Birdwatcher. It has a 2' wide by eight foot long open slot down the center of the "Birdwatcher" type acrylic house. At night and during rainy days I use five pieces of 1/2" pvc pipe wedged between the two slot beams with a 36" wide piece of polytarp (white) stretched over the "hoops". It has never let any rain into the cabin, the ends can be lifted to let in a breeze or tied down to keep the wind out. Twice I've had to sail with the hoops and tarp in place because of unseasonable rain, cabin remained dry.
Rick
daveydimwit <david@...> wrote:
I have been reading the postings on BW and no one seems to deal with
what happens when it rains.
I live in BC and when it rains, it rains a lot.
[Non-text portions of this message have been removed]
Rick
daveydimwit <david@...> wrote:
I have been reading the postings on BW and no one seems to deal with
what happens when it rains.
I live in BC and when it rains, it rains a lot.
[Non-text portions of this message have been removed]
David--PCB designed a Birdwatcher type boat called 'Camper' expressly for sail/row cruising in the BC area. Camper features a gaff sail on a tabernacle; when towered, the mast (along with boom and gaff) form a ridge pole fpr fabric hatch covers. This arrangement is supposed to provide enough head room to row the boat.If you go to the files section of this group and look under 'birdwatcher', the drawings are the drawings for Camper.
John T
John T
----- Original Message -----
From: daveydimwit
To:bolger@yahoogroups.com
Sent: Tuesday, July 27, 2004 7:26 PM
Subject: [bolger] Birdwatcher
I have been reading the postings on BW and no one seems to deal with
what happens when it rains.
I live in BC and when it rains, it rains a lot. I have seen items os
BW before but the latest article in Wooden Boat has rekindled my
interest.
I would love to put one together but I have to figure out how to
survive a two week gunkholing trip when it rained every second day.
Has anyone done a trip in a BW and dealt with rainy weather.
David
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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ADVERTISEMENT
------------------------------------------------------------------------------
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a.. To visit your group on the web, go to:
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c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
[Non-text portions of this message have been removed]
I have been reading the postings on BW and no one seems to deal with
what happens when it rains.
I live in BC and when it rains, it rains a lot. I have seen items os
BW before but the latest article in Wooden Boat has rekindled my
interest.
I would love to put one together but I have to figure out how to
survive a two week gunkholing trip when it rained every second day.
Has anyone done a trip in a BW and dealt with rainy weather.
David
what happens when it rains.
I live in BC and when it rains, it rains a lot. I have seen items os
BW before but the latest article in Wooden Boat has rekindled my
interest.
I would love to put one together but I have to figure out how to
survive a two week gunkholing trip when it rained every second day.
Has anyone done a trip in a BW and dealt with rainy weather.
David
>I feel better knowing it's glass on both sides, though it's still a
> The test was with 4 oz. on both sides of the cedar. This was test
> for puncture resistance not for stiffness.
pretty unbelieveable case.
What's the reference for this? I remember reading something very
similar in their strips report in Epoxyworks. I find it hard to
believe it's puncture resistance, if so what relevance are the
deflection numbers. Or anything much else since puncture is totaly
corelated to the shape of the object doing the puncturing. Sounds
like destructive testing to me.
If it is puncture resistence by some pointy object, then the numbers
are off the chart irrelevant. 400 pounds applied to a sharp stick
when the pressure per inch is 6 pounds.
Anyway, I've been wrong so often before...
--- Inbolger@yahoogroups.com, "proaconstrictor"
<proaconstrictor@y...> wrote:
for puncture resistance not for stiffness.
<proaconstrictor@y...> wrote:
> Who uses 3/8" cedar with 4 oz on one side? A similar test of 3/8axis,
> cedar with with 5oz linear carbon on both side of it in the 90
> is equivalent to 1" dfir. Or with 12 oz biax glass.up
>
> Also it's real tough to get a curve into 3/8" ply, and you load it
> in undesireable ways. meanwhile 3/8" strip can have dramaticcurves
> in the 90 axis which make much re-inforcement unecesary.The test was with 4 oz. on both sides of the cedar. This was test
> snip
for puncture resistance not for stiffness.
Who uses 3/8" cedar with 4 oz on one side? A similar test of 3/8
cedar with with 5oz linear carbon on both side of it in the 90 axis,
is equivalent to 1" dfir. Or with 12 oz biax glass.
Also it's real tough to get a curve into 3/8" ply, and you load it up
in undesireable ways. meanwhile 3/8" strip can have dramatic curves
in the 90 axis which make much re-inforcement unecesary.
The tests are valid and all that, but they seem to overstate what
really happens, which is that you can build dramaticaly efficient
structures with lightly glassed ply or strip. Many ocean going
sailboats have little more that 4 oz on them. and ditto with strip.
For instance a 26 x 6 foot sharpie with 5000 pound displacement would
have around 30 pounds/square foot pressure on it's hull surfaces.
And that's on heavy sharpie.
A sixteen foot canoe with a displacement of 200 pounds, would have
something like 6 pounds of pressure/square foot.
In both cases those are panels secured by their edges, not just
framed in a jig.
cedar with with 5oz linear carbon on both side of it in the 90 axis,
is equivalent to 1" dfir. Or with 12 oz biax glass.
Also it's real tough to get a curve into 3/8" ply, and you load it up
in undesireable ways. meanwhile 3/8" strip can have dramatic curves
in the 90 axis which make much re-inforcement unecesary.
The tests are valid and all that, but they seem to overstate what
really happens, which is that you can build dramaticaly efficient
structures with lightly glassed ply or strip. Many ocean going
sailboats have little more that 4 oz on them. and ditto with strip.
For instance a 26 x 6 foot sharpie with 5000 pound displacement would
have around 30 pounds/square foot pressure on it's hull surfaces.
And that's on heavy sharpie.
A sixteen foot canoe with a displacement of 200 pounds, would have
something like 6 pounds of pressure/square foot.
In both cases those are panels secured by their edges, not just
framed in a jig.
--- Inbolger@yahoogroups.com, "Mike Walsh" <micwal_va@h...> wrote:
> A flat 12" square of 1/4" occume marine ply uncoated weighing 10.7
> oz. will stand about 225 lbs. of force and fail with .63" of
> deflection. With 1 layer of 4 oz. glass it fails at about 430 lbs.
> @.79" deflection and weighs 12.8 oz. With glass it weighs 17% more
> but has 48% more strength.
>
> 3/8" cedar strip planking weighs 12.7 with 4 oz glass will fail at
> 250 lbs @ .42" deflection. 3/8 with two 6 oz. layers weighs 15.4
oz.
> fails at 823 lbs. @.51" defletion. Notice that the pressure
> increases by 18% but the failure rate goes up by 330%.
>
> My guess is the numbers hold up proportionally between the ply and
> the ceder strip, then adding two six oz. layers of glass to the ply
> may bring it up to about about 1200 lbs. before failure. I am
> referring here to puncture resistance not stiffness. If you wish
to
> make the panel stiffer you should increase the core thickness. If
I
> remember right, if you double the thickness of the core you cube
the
> stiffness.
>
> The above assumes at normal wet layup at 60 degrees using West
System
> Epoxy tested on an MTS Tensile tester applying pressure over a 1"
> area.
>
> These numbers are courtesy of James R. Watson of Gougeon Brothers
aka
> West System Epoxy from Ted Moores's "KayakCraft" book.
>
>
> snip
>
> > the hull, and fiberglass doesn't do as well in compression as it
> does in
> > tension But it is not just a mat to hold epoxy. The glass fiber
is
> held
> > in matrix by the epoxy and combined with the plywood makes a
> composite
> > structure that is stronger, tougher, and more durable than the
sum
> of
> > it's parts.
> >
> > I think.
> >
> > See Ya
> >
> > Have Fun
> >
> > Bruce
> >
> >http://myweb.cableone.net/bcanderson/
>for
> Certainly you can use layers of fiberglass as an ablative shielding
> the hull, and fiberglass doesn't do as well in compression as itdoes in
> tension But it is not just a mat to hold epoxy. The glass fiber isheld
> in matrix by the epoxy and combined with the plywood makes acomposite
> structure that is stronger, tougher, and more durable than the sumof
> it's parts.I agree. On the other hand, the gougeons of West fame say that when
>
> I think.
designing these structures you should just think of glass as a screed
to hold epoxy film, and as structuraly equal to, or even less than an
equal amount of wood. Of course where ball peen hammers are
concerned the glass has it's place. This also assume a ply like
wood, so there is crossgrain coming from something.
>
> See Ya
>
> Have Fun
>
> Bruce
>
>http://myweb.cableone.net/bcanderson/
--- Inbolger@yahoogroups.com, "JW Kelley" <jonkel49@y...> wrote:
happening that would still be a lot. The real question is how does
it compare to equal weight plywood, which might even be oin the 3/8"
minus range like 8mm?
> I've read a sandwich glass-wood-glass does increase the strengththis
> considerably. My own tests with a chipping hammer seem to bear
> out. I have to hit 1/4 luan glassed on both side a lot harder thanIt's the square of thickness, so if there wasn't anything else
> one sided glass or no glass at all.
>
happening that would still be a lot. The real question is how does
it compare to equal weight plywood, which might even be oin the 3/8"
minus range like 8mm?
>When I built my Frolic2, it called for 1/2" bottom panels and 1/4" side
> I am curious what the test would
> show for 5/16" and 3/8" un-glassed
> plywood?
panels. I got a great deal on 3/8" plywood so with Jim Michalak's approval,
I used 3/8" on the bottom but glassed both sides with 4 oz. cloth. I got a
more oil canning on the bottom than the 1/2" would have given. ( Previous
experience ). On the flip side, it felt secure without the typical creaks
and groans that plywood under stress can voice. At least from my
experience, the 3/8" plywood glassed on both sides was as strong or stronger
than 1/2" plywood with just epoxy with the benefit better abrasion
protection. On the down side is the labor, tons of it when glassing rather
than flow coating only. On a trailer boat, I don't think I would glass
again, just coat with epoxy and keep an eye on the bottom for gouges. I
think I'd even go to the next size plywood to stay away from glassing.
How's that for an opinion from someone who is 2/3 done glassing about 100
yards of 60" cloth and 45 gallons of epoxy for the Wyoming. But, she'll be
living in the water, not on a trailer.
Jeff
> A flat 12" square of 1/4" occumeSome [much] of this increased strength
> marine ply uncoated
> oz. will stand about 225 lbs.
>
> With 1 layer of 4 oz. glass
> about 430 lbs.
comes from the fact that the outer
surfaces are reinforced with fiberglass
which has good tensile strength, but
some of the strength comes from the
fact that the plywood with glass is
thicker.
I am curious what the test would
show for 5/16" and 3/8" un-glassed
plywood?
A flat 12" square of 1/4" occume marine ply uncoated weighing 10.7
oz. will stand about 225 lbs. of force and fail with .63" of
deflection. With 1 layer of 4 oz. glass it fails at about 430 lbs.
@.79" deflection and weighs 12.8 oz. With glass it weighs 17% more
but has 48% more strength.
3/8" cedar strip planking weighs 12.7 with 4 oz glass will fail at
250 lbs @ .42" deflection. 3/8 with two 6 oz. layers weighs 15.4 oz.
fails at 823 lbs. @.51" defletion. Notice that the pressure
increases by 18% but the failure rate goes up by 330%.
My guess is the numbers hold up proportionally between the ply and
the ceder strip, then adding two six oz. layers of glass to the ply
may bring it up to about about 1200 lbs. before failure. I am
referring here to puncture resistance not stiffness. If you wish to
make the panel stiffer you should increase the core thickness. If I
remember right, if you double the thickness of the core you cube the
stiffness.
The above assumes at normal wet layup at 60 degrees using West System
Epoxy tested on an MTS Tensile tester applying pressure over a 1"
area.
These numbers are courtesy of James R. Watson of Gougeon Brothers aka
West System Epoxy from Ted Moores's "KayakCraft" book.
snip
oz. will stand about 225 lbs. of force and fail with .63" of
deflection. With 1 layer of 4 oz. glass it fails at about 430 lbs.
@.79" deflection and weighs 12.8 oz. With glass it weighs 17% more
but has 48% more strength.
3/8" cedar strip planking weighs 12.7 with 4 oz glass will fail at
250 lbs @ .42" deflection. 3/8 with two 6 oz. layers weighs 15.4 oz.
fails at 823 lbs. @.51" defletion. Notice that the pressure
increases by 18% but the failure rate goes up by 330%.
My guess is the numbers hold up proportionally between the ply and
the ceder strip, then adding two six oz. layers of glass to the ply
may bring it up to about about 1200 lbs. before failure. I am
referring here to puncture resistance not stiffness. If you wish to
make the panel stiffer you should increase the core thickness. If I
remember right, if you double the thickness of the core you cube the
stiffness.
The above assumes at normal wet layup at 60 degrees using West System
Epoxy tested on an MTS Tensile tester applying pressure over a 1"
area.
These numbers are courtesy of James R. Watson of Gougeon Brothers aka
West System Epoxy from Ted Moores's "KayakCraft" book.
snip
> the hull, and fiberglass doesn't do as well in compression as itdoes in
> tension But it is not just a mat to hold epoxy. The glass fiber isheld
> in matrix by the epoxy and combined with the plywood makes acomposite
> structure that is stronger, tougher, and more durable than the sumof
> it's parts.
>
> I think.
>
> See Ya
>
> Have Fun
>
> Bruce
>
>http://myweb.cableone.net/bcanderson/
I responded earlier with a post about scrapers...this is a link to
the magazine I read the article in....it is posted here in full.
http://westsystem.com/ewmag/19/Scrapers.html
--- Inbolger@yahoogroups.com, "Bruce C. Anderson" <bcanderson@c...>
wrote:
the magazine I read the article in....it is posted here in full.
http://westsystem.com/ewmag/19/Scrapers.html
--- Inbolger@yahoogroups.com, "Bruce C. Anderson" <bcanderson@c...>
wrote:
> Howdy
>
> > -----Original Message-----
> > From: Roger Derby [mailto:derbyrm@s...]
> > Sent: Saturday, September 13, 2003 7:47 PM
> > To:bolger@yahoogroups.com
> > Subject: Re: [bolger] Re: Preglassing AND Polyester film
> >
> >
> snip>
> Have Fun
>
> Bruce
>
>http://myweb.cableone.net/bcanderson/
Roger Derby wrote:
gouges until we can patch 'em up?
submerged containers......
Rick-
> At least one expert I read suggested that the glass on the outside of aAnd isn't that what most of us here need, a bit of protection against the normal scrapes and
> plywood boat was there simply to reinforce the epoxy and allow a thicker
> coat to insure waterproofing after the normal scrapes and gouges.
gouges until we can patch 'em up?
>From what I've read on this board few, if any of us will be encountering those half
>
> It seems to me that if you're going to be ramming the corners of half
> submerged containers, the glass should be on the inside where the skin is in
> tension, not compression. I don't think fiberglass adds much to the
> compression strength.
submerged containers......
Rick-
Howdy
saying that the last 1/2 inch of steel on a 1" steel hull is just there
to insure waterproofing after
the normal scrapes and gouges. That guy us obviously has no idea what
the glass fibers do.
Certainly you can use layers of fiberglass as an ablative shielding for
the hull, and fiberglass doesn't do as well in compression as it does in
tension But it is not just a mat to hold epoxy. The glass fiber is held
in matrix by the epoxy and combined with the plywood makes a composite
structure that is stronger, tougher, and more durable than the sum of
it's parts.
I think.
See Ya
Have Fun
Bruce
http://myweb.cableone.net/bcanderson/
> -----Original Message-----That's what you get when you talk to experts. That's equivalent to
> From: Roger Derby [mailto:derbyrm@...]
> Sent: Saturday, September 13, 2003 7:47 PM
> To:bolger@yahoogroups.com
> Subject: Re: [bolger] Re: Preglassing AND Polyester film
>
>
> At least one expert I read suggested that the glass on the
> outside of a plywood boat was there simply to reinforce the
> epoxy and allow a thicker coat to insure waterproofing after
> the normal scrapes and gouges.
saying that the last 1/2 inch of steel on a 1" steel hull is just there
to insure waterproofing after
the normal scrapes and gouges. That guy us obviously has no idea what
the glass fibers do.
Certainly you can use layers of fiberglass as an ablative shielding for
the hull, and fiberglass doesn't do as well in compression as it does in
tension But it is not just a mat to hold epoxy. The glass fiber is held
in matrix by the epoxy and combined with the plywood makes a composite
structure that is stronger, tougher, and more durable than the sum of
it's parts.
I think.
See Ya
Have Fun
Bruce
http://myweb.cableone.net/bcanderson/
I've read a sandwich glass-wood-glass does increase the strength
considerably. My own tests with a chipping hammer seem to bear this
out. I have to hit 1/4 luan glassed on both side a lot harder than
one sided glass or no glass at all.
considerably. My own tests with a chipping hammer seem to bear this
out. I have to hit 1/4 luan glassed on both side a lot harder than
one sided glass or no glass at all.
--- Inbolger@yahoogroups.com, "Roger Derby" <derbyrm@s...> wrote:
> At least one expert I read suggested that the glass on the outside
of a
> plywood boat was there simply to reinforce the epoxy and allow a
thicker
> coat to insure waterproofing after the normal scrapes and gouges.
>
> It seems to me that if you're going to be ramming the corners of
half
> submerged containers, the glass should be on the inside where the
skin is in
> tension, not compression. I don't think fiberglass adds much to
the
> compression strength.
>
> Roger
> derbyrm@s...
>http://derbyrm.mystarband.net
>
> ----- Original Message -----
> From: "Bruce Hallman" <bruce@h...>
> To: <bolger@yahoogroups.com>
> Sent: Saturday, September 13, 2003 12:09 PM
> Subject: Re: [bolger] Re: Preglassing AND Polyester film
>
>
> >
> > > I coulda sworn I read somewhere about
> > > the vastly improved physical
> > > properties of a glass-ply-glass sandwich.
> > > Something about having the
> > > tensile strength on the inside too,
> > > where in an impact, the wood is
> > > burst apart.
> >
> > I agree that plywood with fiberglass
> > and epoxy both sides is strong, and
> > the reason I believe so it that fiber-
> > glass has good tensile strength and
> > that epoxy is relatively impermeable.
> >
> > But, at a cost. Thick enough plywood, with
> > factory applied MDO overlay, is a cheaper
> > way to gain strength with durability.
> > [me thinks]
> >
> > The time and cost saved could be spent
> > on teak and brass trim work! :)
At least one expert I read suggested that the glass on the outside of a
plywood boat was there simply to reinforce the epoxy and allow a thicker
coat to insure waterproofing after the normal scrapes and gouges.
It seems to me that if you're going to be ramming the corners of half
submerged containers, the glass should be on the inside where the skin is in
tension, not compression. I don't think fiberglass adds much to the
compression strength.
Roger
derbyrm@...
http://derbyrm.mystarband.net
plywood boat was there simply to reinforce the epoxy and allow a thicker
coat to insure waterproofing after the normal scrapes and gouges.
It seems to me that if you're going to be ramming the corners of half
submerged containers, the glass should be on the inside where the skin is in
tension, not compression. I don't think fiberglass adds much to the
compression strength.
Roger
derbyrm@...
http://derbyrm.mystarband.net
----- Original Message -----
From: "Bruce Hallman" <bruce@...>
To: <bolger@yahoogroups.com>
Sent: Saturday, September 13, 2003 12:09 PM
Subject: Re: [bolger] Re: Preglassing AND Polyester film
>
> > I coulda sworn I read somewhere about
> > the vastly improved physical
> > properties of a glass-ply-glass sandwich.
> > Something about having the
> > tensile strength on the inside too,
> > where in an impact, the wood is
> > burst apart.
>
> I agree that plywood with fiberglass
> and epoxy both sides is strong, and
> the reason I believe so it that fiber-
> glass has good tensile strength and
> that epoxy is relatively impermeable.
>
> But, at a cost. Thick enough plywood, with
> factory applied MDO overlay, is a cheaper
> way to gain strength with durability.
> [me thinks]
>
> The time and cost saved could be spent
> on teak and brass trim work! :)
> I coulda sworn I read somewhere aboutI agree that plywood with fiberglass
> the vastly improved physical
> properties of a glass-ply-glass sandwich.
> Something about having the
> tensile strength on the inside too,
> where in an impact, the wood is
> burst apart.
and epoxy both sides is strong, and
the reason I believe so it that fiber-
glass has good tensile strength and
that epoxy is relatively impermeable.
But, at a cost. Thick enough plywood, with
factory applied MDO overlay, is a cheaper
way to gain strength with durability.
[me thinks]
The time and cost saved could be spent
on teak and brass trim work! :)
> Isn't the biggest reason for fiberglassBruce --
> over plywood the protection of the plywood
> from checks and rot? I don't believe
> that fiberglassing plywood is a cost
> effective way of increasing the strength.
> For that, it is smarter to just use a
> thicker piece of plywood.
I coulda sworn I read somewhere about the vastly improved physical
properties of a glass-ply-glass sandwich. Something about having the
tensile strength on the inside too, where in an impact, the wood is
burst apart.
I've certainly noticed this effect on a small scale with my Toto
canoe -- where a bare ply bilge panel (luaun) that caught a rock
while I paddled our local river got punched through easily. Simple
glass over ply on the bottom allows me to hit and slide over rocks,
though sometimes the plywood will part, and a crease will open in the
wood -- even though the glass outside is preventing water from coming
in. I figure the final step of that progression is to glass both
sides.
I'd rather go with the glass-ply-glass sandwich than with heavier ply
for Cormorant, as it's going to be plenty big and heavy already, and
I need to keep the weight down for trailering.
I'll have to go do a bit of research to find where I read about the
properties of the composite, and see if it's merely wishful thinking
(or faulty memory) on my part.
All best,
Garth
I used MDO to make new floorboards for Alisa and to replace a lost
hatch off of Cream Cheese. I like working with it, but there were
more voids in the plywood than I like. I guess it all depends on the
manufacturer and batch.
Frank
hatch off of Cream Cheese. I like working with it, but there were
more voids in the plywood than I like. I guess it all depends on the
manufacturer and batch.
Frank
--- Inbolger@yahoogroups.com, Bruce Hallman <bruce@h...> wrote:
> --- GarthAB wrote:
> > MDO no glass
> > Not so strong as composite
> > Cherry blossoms, tea.
>
> <big smile>
>
> Well, MDO is specified by lots of
> high powered designers for use in
> long term 'outdoors' applications,
> for instance for use by highway
> sign makers. It lasts for decades
> out in full exposure to the weather
> with no more protection than paint.
>
> The underlying plywood is just as
> strong as APA rated 'fir' plywood.
>
> Isn't the biggest reason for fiberglass
> over plywood the protection of the plywood
> from checks and rot? I don't believe
> that fiberglassing plywood is a cost
> effective way of increasing the strength.
> For that, it is smarter to just use a
> thicker piece of plywood.
>
> MDO does a darn good job protecting the
> faces of plywood from checking. I would
> still put epoxy on the edges, and certainly
> use a coat of high quality paint all over too.
>
> If your goal is protecting the plywood from impacts,
> I would use another fabric instead of fiberglass,
> like Xynol.
>
> This is what the Raka User Manual says about it:
>
> "When fiberglassing, remember that most wooden boat
> designs get their strength from the wood. Epoxy and
> wood have different strength characteristics. Usually
> a plywood boat has a light layer of fiberglass applied
> to the surface for water and abrasion resistance only.
> Too heavy a fiberglass covering will just increase
> weight and expense. This advice of course is general
> and a designers specifications should always be
> followed, especially when choosing materials for
> reinforcing things such as in seams and bulkheads."
--- GarthAB wrote:
Well, MDO is specified by lots of
high powered designers for use in
long term 'outdoors' applications,
for instance for use by highway
sign makers. It lasts for decades
out in full exposure to the weather
with no more protection than paint.
The underlying plywood is just as
strong as APA rated 'fir' plywood.
Isn't the biggest reason for fiberglass
over plywood the protection of the plywood
from checks and rot? I don't believe
that fiberglassing plywood is a cost
effective way of increasing the strength.
For that, it is smarter to just use a
thicker piece of plywood.
MDO does a darn good job protecting the
faces of plywood from checking. I would
still put epoxy on the edges, and certainly
use a coat of high quality paint all over too.
If your goal is protecting the plywood from impacts,
I would use another fabric instead of fiberglass,
like Xynol.
This is what the Raka User Manual says about it:
"When fiberglassing, remember that most wooden boat
designs get their strength from the wood. Epoxy and
wood have different strength characteristics. Usually
a plywood boat has a light layer of fiberglass applied
to the surface for water and abrasion resistance only.
Too heavy a fiberglass covering will just increase
weight and expense. This advice of course is general
and a designers specifications should always be
followed, especially when choosing materials for
reinforcing things such as in seams and bulkheads."
> MDO no glass<big smile>
> Not so strong as composite
> Cherry blossoms, tea.
Well, MDO is specified by lots of
high powered designers for use in
long term 'outdoors' applications,
for instance for use by highway
sign makers. It lasts for decades
out in full exposure to the weather
with no more protection than paint.
The underlying plywood is just as
strong as APA rated 'fir' plywood.
Isn't the biggest reason for fiberglass
over plywood the protection of the plywood
from checks and rot? I don't believe
that fiberglassing plywood is a cost
effective way of increasing the strength.
For that, it is smarter to just use a
thicker piece of plywood.
MDO does a darn good job protecting the
faces of plywood from checking. I would
still put epoxy on the edges, and certainly
use a coat of high quality paint all over too.
If your goal is protecting the plywood from impacts,
I would use another fabric instead of fiberglass,
like Xynol.
This is what the Raka User Manual says about it:
"When fiberglassing, remember that most wooden boat
designs get their strength from the wood. Epoxy and
wood have different strength characteristics. Usually
a plywood boat has a light layer of fiberglass applied
to the surface for water and abrasion resistance only.
Too heavy a fiberglass covering will just increase
weight and expense. This advice of course is general
and a designers specifications should always be
followed, especially when choosing materials for
reinforcing things such as in seams and bulkheads."
MDO no glass
Not so strong as composite
Cherry blossoms, tea.
(Just trying to get that Basho feeling into my poem . . .)
--G
Not so strong as composite
Cherry blossoms, tea.
(Just trying to get that Basho feeling into my poem . . .)
--G
--- Inbolger@yahoogroups.com, Bruce Hallman <bruce@h...> wrote:
> Medium Density Overlay
> Both sides all ready!
> Much sanding saved.
>
> --- GarthAB wrote:
> > love that haiku.
Medium Density Overlay
Both sides all ready!
Much sanding saved.
--- GarthAB wrote:
Both sides all ready!
Much sanding saved.
--- GarthAB wrote:
> love that haiku.
This is a good reason to preglass, and it is a great idea. There are
more and more savy designers specking this due to very much lower
maintenance, of course it is a lot of work, so it needs to be on a
serious boat.
a scrape, and that your inner glass won't help. But inner glass and
very careful detailing does help a lot. The worst areas for rot are
still the underside of decks unless well aired, the shears, and
unless well detailed it can spread anywhere, and any sealed
compartments.
more and more savy designers specking this due to very much lower
maintenance, of course it is a lot of work, so it needs to be on a
serious boat.
> to seep in through microcracks. The upside is much greater punctureof
> resistance, i.e. by a sharp rock or a big log. The glass-plywood-
> glass composite is very strong. (I read the specs on the physical
> properties somewhere -- can't remember now, but it was by a factor
> two or three over outside glass on ply, I think, and by an evenMaybe, the real problem comes with getting wacked into the wood, from
> larger factor over ply alone.)
a scrape, and that your inner glass won't help. But inner glass and
very careful detailing does help a lot. The worst areas for rot are
still the underside of decks unless well aired, the shears, and
unless well detailed it can spread anywhere, and any sealed
compartments.
> So . . . preglassing makes the inner side glassing much easier.Bolger/Michalak
> Not to mention avoiding sanding inside a big boat.
>
> All best,
> Garth
>
> PS Frank -- love that haiku. We could start a whole
> haiku folder in the files.
>
> Polyester film
> Smooth epoxy like water
> But is it helpful?
> Also consider skipping the glass byPart of the reason I'm preglassing is that I'd like to glass both
> using pre-overlayed plywood, MDO.
sides. I know this is a whole can of worms in itself -- some will say
it traps water in the wood and creates rot. I figure since it's a
trailer sailer, water will have much more time to evaporate out than
to seep in through microcracks. The upside is much greater puncture
resistance, i.e. by a sharp rock or a big log. The glass-plywood-
glass composite is very strong. (I read the specs on the physical
properties somewhere -- can't remember now, but it was by a factor of
two or three over outside glass on ply, I think, and by an even
larger factor over ply alone.)
So . . . preglassing makes the inner side glassing much easier.
Not to mention avoiding sanding inside a big boat.
All best,
Garth
PS Frank -- love that haiku. We could start a whole Bolger/Michalak
haiku folder in the files.
Polyester film
Smooth epoxy like water
But is it helpful?
> GarthAB wrote:Also consider skipping the glass by
> preglass flat.
using pre-overlayed plywood, MDO.
I don't prefinish because of secondary bonding issues, not that I
worry much about that, but it's at least a point. Also you usualy
waste a lot of material, and you still have to fair the outside if
any tape is used to join hulls, or glass wrapped over assembled
pieces. A lot of Bolger designs have pretty heavy bends in them, if
you pre-finish, this makes maters worse, and rather than the
sheathing material adding to the strength and stiffness, it ends up
stressed so that impact and water loads are returnign it to neutral.
Also when you longi bend the panels, they are more likely to concave.
Think drywall. No mater how smooth the panels are, essentialy
prefinished the job looks a lot better and is faster to just skim
coat, rather than taping just the joints. Which explains why
Blueboard is gaining in popularity.
1 dollar a square foot is more expensive than real peel ply,
presumably more expensive than the 3M stuff Kurt Hughes uses and
recomends. With molded boats the glass goes on on a finished plug
like foam base, so anythign you can do to smooth it at that stage is
a permanent advantage.
Anyway, experimentation is what makes all this fun.
worry much about that, but it's at least a point. Also you usualy
waste a lot of material, and you still have to fair the outside if
any tape is used to join hulls, or glass wrapped over assembled
pieces. A lot of Bolger designs have pretty heavy bends in them, if
you pre-finish, this makes maters worse, and rather than the
sheathing material adding to the strength and stiffness, it ends up
stressed so that impact and water loads are returnign it to neutral.
Also when you longi bend the panels, they are more likely to concave.
Think drywall. No mater how smooth the panels are, essentialy
prefinished the job looks a lot better and is faster to just skim
coat, rather than taping just the joints. Which explains why
Blueboard is gaining in popularity.
1 dollar a square foot is more expensive than real peel ply,
presumably more expensive than the 3M stuff Kurt Hughes uses and
recomends. With molded boats the glass goes on on a finished plug
like foam base, so anythign you can do to smooth it at that stage is
a permanent advantage.
Anyway, experimentation is what makes all this fun.
--- Inbolger@yahoogroups.com, John Ewing <john.ewing@s...> wrote:
> The best finish I've see in plywood boats (almost too good, since
many
> folks take it for fibreglass construction) comes out of Sam Devlin's
> shop in Olympia, WA - on S&G boats up to 45 feet (so far). Having
> visited relatively recently, I'm pretty certain Sam doesn't pre-
finish
> his plywood. It might be worthwhile discussing the pros and cons
with
> him.
>http://www.devlinboat.com/
>
> JohnE.
>
>
> [Non-text portions of this message have been removed]
craig o'donnell wrote:
death inside a tangled mess of shrinkwrap.
Actually, I wonder if the shrinkwrap is thick enough? I think the polyfilm thickness has a
lot to do with it's success.
Rick-
> Occurs to me that on curves, it might be possible to use thatOh great, now they'll find an epoxy coated hair dryer lying next to me after I'm squeezed to
> window-sealing shrinkwrap and snug the film down against the epoxy
> and glass with a hair dryer. As someone manetioned, this may not
> necessarily be as fair as possible, but it's worth a try. If I have
> such a project I'll give it a shot.
> --
> Craig O'Donnell
> Sinepuxent Ancestors & Boats
death inside a tangled mess of shrinkwrap.
Actually, I wonder if the shrinkwrap is thick enough? I think the polyfilm thickness has a
lot to do with it's success.
Rick-
Peter Lenihan wrote:
out a section of the laid out glass cloth, spread it with the squeegee, unroll some of the
polyfilm, roller the air bubbles out, repeat.....
It seems to me a key component here is the roller. Something wide 8"-10" and as large
diameter as possible, plus composed of something rather firm. I'll have to go back to John's
page and see what he used.
and put your efforts to where it counts.
Rick-
> --Might be a good idea to have the precut polyfilm rolled up on and empty cardboard tube. Wet
>
> > The filming and rolling will add a pair of time sensitive
> processes to the glassing.
>
> This is good to consider since you will/can certainly be intimidated
> by the size of the assembled panels. Stressing yourself out further
> may not ensure there are no mistakes.
out a section of the laid out glass cloth, spread it with the squeegee, unroll some of the
polyfilm, roller the air bubbles out, repeat.....
It seems to me a key component here is the roller. Something wide 8"-10" and as large
diameter as possible, plus composed of something rather firm. I'll have to go back to John's
page and see what he used.
> a clear consistant vision of howBig point. Big, big point.
> you want your boat done is needed before going this route,otherwise
> the effort of getting the incredible surface may be lost if;a)it is
> on the bottom and always underwater,
> b) you WANT a simple/lowYes, you have to learn that some times you have to say "good enough" on a certain area/task
> maintainence boat and c) it serves to "drive" the rest of the work
> and consumes so much time going for perfection EVERYWHERE that you
> take up full time drinking,forget all about launch dates and why you
> are building this boat and simply lose your mind.
and put your efforts to where it counts.
Rick-
GarthAB wrote:
Do you have a table big enough to hold a full size panel?
My guess is this polyfilm has to be pretty thick and the roller technique needs to be
uniform to get this right.
Firmly scraping down the epoxied glass cloth to the top of the weave with a tapers knife
when almost tacky really cuts down on drips and runs. Then once tack free, but still green,
filing the weave with a sandable filler is a time tested method.
huge flat area
I do however take a swipe with a grinder or sanding disc at the edge where the routering
stops to sort of taper it out avoiding a hard edge. I'm not sure it's necessary, but I
wanted a tapered transition, not a hard line. This also works to set a glass tape butt block
flush to the panels avoiding most of the fairing.
go over the glassed cloth and then you build up the seam to the level of the panel? I've had
better results with building up a seam to flush rather than grinding down.
smoother finish...
well worth the effort.
Rick-
> Hi Rick --Preglass flat is great, especially with panels this size
>
> My thinking was: whenever I epoxy/glass a boat, I get a lot
> of drips and runs and bumps. So I may as well preglass flat.
Do you have a table big enough to hold a full size panel?
My guess is this polyfilm has to be pretty thick and the roller technique needs to be
uniform to get this right.
Firmly scraping down the epoxied glass cloth to the top of the weave with a tapers knife
when almost tacky really cuts down on drips and runs. Then once tack free, but still green,
filing the weave with a sandable filler is a time tested method.
> Okay --Agreed, anything to reduce sanding... This sure looks like a fast and clean way to glass a
> then there's still a lot of sanding to do -- about an acre of it, I
> think. ;-) So if the film technique levels out the surface and allows
> just a light buffing with fine paper or Scotchbright to ready it for
> paint, I'm happy.
huge flat area
>Even a 6" tapers knife will fair in the edge of the taped seam.,
>
> About the taped seams -- yes, a problem there, joining them to the
> gleaming filmed surface. But I'm not really looking for perfection
> all around -- just saving a bit of time and epoxy, with the added
> benefit of a surface that's mostly smooth, far better than I could've
> done it without the film. (Though I've never tried your 12" drywall
> knife technique.)
>Consider a router set to slightly more than the finished tape thickness, fast and accurate.
> My planned process is this: power-plane out or grind out 2" or 3"
> at the panel edges so the tapes sink down to the level of the
> surrounding wood.
I do however take a swipe with a grinder or sanding disc at the edge where the routering
stops to sort of taper it out avoiding a hard edge. I'm not sure it's necessary, but I
wanted a tapered transition, not a hard line. This also works to set a glass tape butt block
flush to the panels avoiding most of the fairing.
> When preglassing the whole panel, cut the glassMaybe run the glass cloth down into the hollowed out area a bit so that the glass tape will
> cloth off there, and mask the hollowed area with tape. After glassing
> panel and filming it, peel up tape, and you have a raw wood edge
> ready for the tape.
go over the glassed cloth and then you build up the seam to the level of the panel? I've had
better results with building up a seam to flush rather than grinding down.
> Glass and fill the tape, maybe go around with aI've had excellent results doing this using peel ply, but the polyfilm would leave a much
> small piece of the film just smoothin it as best I can.
smoother finish...
> It's just less of the filling/sanding I'd be doing on the wholeFilling isn't so bad, but anything you can do to reduce sanding (including less filling) is
> surface otherwise.
well worth the effort.
>Good, lets hear more
>
> Okay -- more thoughts on this, but I've been informed it's time to
> drive my daughter to school!
Rick-
>
>
> All best,
> Garth
>
>
The best finish I've see in plywood boats (almost too good, since many
folks take it for fibreglass construction) comes out of Sam Devlin's
shop in Olympia, WA - on S&G boats up to 45 feet (so far). Having
visited relatively recently, I'm pretty certain Sam doesn't pre-finish
his plywood. It might be worthwhile discussing the pros and cons with
him.
http://www.devlinboat.com/
JohnE.
[Non-text portions of this message have been removed]
folks take it for fibreglass construction) comes out of Sam Devlin's
shop in Olympia, WA - on S&G boats up to 45 feet (so far). Having
visited relatively recently, I'm pretty certain Sam doesn't pre-finish
his plywood. It might be worthwhile discussing the pros and cons with
him.
http://www.devlinboat.com/
JohnE.
[Non-text portions of this message have been removed]
I'm pleased to "announce" that with the exception of the tiller
linkage, mast, and CB, the BW I'vehad in rehab for way too long is
painted and seaworthy. Expect to have it in the water at the Mid
Atlantic Small Craft Fest in about a month, though probably not under
sail (no sail, yet). To say this is a victory of sorts ... <chuckle>
I've adopted the "ferryboat finish" plan. Having recently taken a
trip on the Cape-May-Lewes Ferry, I noticed that my painted finish
was at least as nice as theirs, so that's how it'll stay. I'm doing a
lightning rework of an old plywood pram in case I anchor the BW in St
Michaels Harbor.
I've learned a ho' bunch o'lessons which I've promised Chuck to
provide to Duckworks. Now the only hangup is getting a photo of the
craft afloat.
Cheers -- COD
--
Craig O'Donnell
Sinepuxent Ancestors & Boats
<http://freepages.genealogy.rootsweb.com/~fassitt/>
The Proa FAQ <http://boat-links.com/proafaq.html>
The Cheap Pages <http://www2.friend.ly.net/~dadadata/>
Sailing Canoes, Polytarp Sails, Bamboo, Chinese Junks,
American Proas, the Bolger Boat Honor Roll,
Plywood Boats, Bamboo Rafts, &c.
_________________________________
-- Professor of Boatology -- Junkomologist
-- Macintosh kinda guy
Friend of Wanda the Wonder Cat, 1991-1997.
_________________________________
---
[This E-mail scanned for viruses by friend.ly.net.]
linkage, mast, and CB, the BW I'vehad in rehab for way too long is
painted and seaworthy. Expect to have it in the water at the Mid
Atlantic Small Craft Fest in about a month, though probably not under
sail (no sail, yet). To say this is a victory of sorts ... <chuckle>
I've adopted the "ferryboat finish" plan. Having recently taken a
trip on the Cape-May-Lewes Ferry, I noticed that my painted finish
was at least as nice as theirs, so that's how it'll stay. I'm doing a
lightning rework of an old plywood pram in case I anchor the BW in St
Michaels Harbor.
I've learned a ho' bunch o'lessons which I've promised Chuck to
provide to Duckworks. Now the only hangup is getting a photo of the
craft afloat.
Cheers -- COD
--
Craig O'Donnell
Sinepuxent Ancestors & Boats
<http://freepages.genealogy.rootsweb.com/~fassitt/>
The Proa FAQ <http://boat-links.com/proafaq.html>
The Cheap Pages <http://www2.friend.ly.net/~dadadata/>
Sailing Canoes, Polytarp Sails, Bamboo, Chinese Junks,
American Proas, the Bolger Boat Honor Roll,
Plywood Boats, Bamboo Rafts, &c.
_________________________________
-- Professor of Boatology -- Junkomologist
-- Macintosh kinda guy
Friend of Wanda the Wonder Cat, 1991-1997.
_________________________________
---
[This E-mail scanned for viruses by friend.ly.net.]
Occurs to me that on curves, it might be possible to use that
window-sealing shrinkwrap and snug the film down against the epoxy
and glass with a hair dryer. As someone manetioned, this may not
necessarily be as fair as possible, but it's worth a try. If I have
such a project I'll give it a shot.
--
Craig O'Donnell
Sinepuxent Ancestors & Boats
<http://freepages.genealogy.rootsweb.com/~fassitt/>
The Proa FAQ <http://boat-links.com/proafaq.html>
The Cheap Pages <http://www2.friend.ly.net/~dadadata/>
Sailing Canoes, Polytarp Sails, Bamboo, Chinese Junks,
American Proas, the Bolger Boat Honor Roll,
Plywood Boats, Bamboo Rafts, &c.
_________________________________
-- Professor of Boatology -- Junkomologist
-- Macintosh kinda guy
Friend of Wanda the Wonder Cat, 1991-1997.
_________________________________
---
[This E-mail scanned for viruses by friend.ly.net.]
window-sealing shrinkwrap and snug the film down against the epoxy
and glass with a hair dryer. As someone manetioned, this may not
necessarily be as fair as possible, but it's worth a try. If I have
such a project I'll give it a shot.
--
Craig O'Donnell
Sinepuxent Ancestors & Boats
<http://freepages.genealogy.rootsweb.com/~fassitt/>
The Proa FAQ <http://boat-links.com/proafaq.html>
The Cheap Pages <http://www2.friend.ly.net/~dadadata/>
Sailing Canoes, Polytarp Sails, Bamboo, Chinese Junks,
American Proas, the Bolger Boat Honor Roll,
Plywood Boats, Bamboo Rafts, &c.
_________________________________
-- Professor of Boatology -- Junkomologist
-- Macintosh kinda guy
Friend of Wanda the Wonder Cat, 1991-1997.
_________________________________
---
[This E-mail scanned for viruses by friend.ly.net.]
Hi Rick --
Your points are all well taken and this whole film thing may be for
nought. My thinking was: whenever I epoxy/glass a boat, I get a lot
of drips and runs and bumps. So I may as well preglass flat. Okay --
then there's still a lot of sanding to do -- about an acre of it, I
think. ;-) So if the film technique levels out the surface and allows
just a light buffing with fine paper or Scotchbright to ready it for
paint, I'm happy.
About the taped seams -- yes, a problem there, joining them to the
gleaming filmed surface. But I'm not really looking for perfection
all around -- just saving a bit of time and epoxy, with the added
benefit of a surface that's mostly smooth, far better than I could've
done it without the film. (Though I've never tried your 12" drywall
knife technique.)
My planned process is this: power-plane out or grind out 2" or 3"
at the panel edges so the tapes sink down to the level of the
surrounding wood. When preglassing the whole panel, cut the glass
cloth off there, and mask the hollowed area with tape. After glassing
panel and filming it, peel up tape, and you have a raw wood edge
ready for the tape. Glass and fill the tape, maybe go around with a
small piece of the film just smoothin it as best I can. Sand, etc.
It's just less of the filling/sanding I'd be doing on the whole
surface otherwise.
Okay -- more thoughts on this, but I've been informed it's time to
drive my daughter to school!
All best,
Garth
Your points are all well taken and this whole film thing may be for
nought. My thinking was: whenever I epoxy/glass a boat, I get a lot
of drips and runs and bumps. So I may as well preglass flat. Okay --
then there's still a lot of sanding to do -- about an acre of it, I
think. ;-) So if the film technique levels out the surface and allows
just a light buffing with fine paper or Scotchbright to ready it for
paint, I'm happy.
About the taped seams -- yes, a problem there, joining them to the
gleaming filmed surface. But I'm not really looking for perfection
all around -- just saving a bit of time and epoxy, with the added
benefit of a surface that's mostly smooth, far better than I could've
done it without the film. (Though I've never tried your 12" drywall
knife technique.)
My planned process is this: power-plane out or grind out 2" or 3"
at the panel edges so the tapes sink down to the level of the
surrounding wood. When preglassing the whole panel, cut the glass
cloth off there, and mask the hollowed area with tape. After glassing
panel and filming it, peel up tape, and you have a raw wood edge
ready for the tape. Glass and fill the tape, maybe go around with a
small piece of the film just smoothin it as best I can. Sand, etc.
It's just less of the filling/sanding I'd be doing on the whole
surface otherwise.
Okay -- more thoughts on this, but I've been informed it's time to
drive my daughter to school!
All best,
Garth
Garth,
Keep us posted on how this works for you. I've been trying to figure if John's technique
would be of any help in my soon (hopefully) to be started Caprice. Although that shiney,
slick finish looks impressive I'm a bit doubtful right now that there is any advantage to it
when assembling such big panels. Maybe I'm not seeing everything? Yes, I understand the
smoother finish and the filled weave, but is it really compressed glass or more straight
epoxy filling the weave?
My reasoning against pre-glassed and filmed panels goes like this...
Pre-glassing the full sized panels will add extra weight to the already heavy panels.
The filming and rolling will add a pair of time sensitive processes to the glassing.
The nearly perfect glassed/filmed/rolled panels are likely to suffer some damage during
handling (at least by me).
There will still be the holes from temporary alignment screws and any alignment wiring ties
that will need filling
The taped seams will have to be faired into those "mirror finish" filmed/rolled panels. I
imagine you could film/roll the tape, but I think they will still need filler to fair the
seams into the preglassed area.
I image much time will pass from the day the first panel is preglassed until the assembled
hull it taped together, so no chance for a green epoxy bond....
The advantages of the "old way" include;
Panels will be lighter without the preglass/filmed epoxy
Any scars, scrapes, holes etc. in panels can be repaired before glassing.
Seams can be taped and faired before glassing.
The glass sheathing will be seamless, covering the panels, taped seams and any fairing..
Spreading an epoxy/filler mix into the weave of "green" sheathing with a 12" drywall knife
is simple, one person, no hurry process that leaves a nice smooth finish that needs only
light sanding to be ready for paint primer.
I need to think this through a bit more.......
Comments?
Rick
GarthAB wrote:
Keep us posted on how this works for you. I've been trying to figure if John's technique
would be of any help in my soon (hopefully) to be started Caprice. Although that shiney,
slick finish looks impressive I'm a bit doubtful right now that there is any advantage to it
when assembling such big panels. Maybe I'm not seeing everything? Yes, I understand the
smoother finish and the filled weave, but is it really compressed glass or more straight
epoxy filling the weave?
My reasoning against pre-glassed and filmed panels goes like this...
Pre-glassing the full sized panels will add extra weight to the already heavy panels.
The filming and rolling will add a pair of time sensitive processes to the glassing.
The nearly perfect glassed/filmed/rolled panels are likely to suffer some damage during
handling (at least by me).
There will still be the holes from temporary alignment screws and any alignment wiring ties
that will need filling
The taped seams will have to be faired into those "mirror finish" filmed/rolled panels. I
imagine you could film/roll the tape, but I think they will still need filler to fair the
seams into the preglassed area.
I image much time will pass from the day the first panel is preglassed until the assembled
hull it taped together, so no chance for a green epoxy bond....
The advantages of the "old way" include;
Panels will be lighter without the preglass/filmed epoxy
Any scars, scrapes, holes etc. in panels can be repaired before glassing.
Seams can be taped and faired before glassing.
The glass sheathing will be seamless, covering the panels, taped seams and any fairing..
Spreading an epoxy/filler mix into the weave of "green" sheathing with a 12" drywall knife
is simple, one person, no hurry process that leaves a nice smooth finish that needs only
light sanding to be ready for paint primer.
I need to think this through a bit more.......
Comments?
Rick
GarthAB wrote:
> To combine a couple of recent threads, I ordered a roll of 20 mil
> Lexan film today from GE Polymershapes (www.gepolymershapes.com/).
> It's 48" wide by 40' long. It cost $1.04 per sq. foot. Sounds a bit
> crazy for a process I haven't tested yet, but I'll take the gamble on
> John Blazy's say-so. I'm impatient to get going on my project before
> cold weather cuts it off.
>
> I'm about to start laying out the panels for my Michalak Cormorant
> (31' trailer-sailer). Basically two very big sidepanels, nearly 4' at
> widest section by 32' long; two slimmer bilge panels, also about 32'
> long, and one humongous bottom panel, about 5'6" at its widest by 20'
> long. I'm going to preglass them all -- and if this polyester film
> technique works, they'll take less epoxy and have a smoother finish,
> saving much sanding time.
>
> With any luck this film will hold up for future boats. Of course,
> I'll have to build many more boats to amortize the extravagant cost
> of the film.
>
> I'll report soon, I hope.
>
> All best,
> Garth
>
> PS I ordered from the Syracuse, NY branch -- 315-422-9165. You can
> also order right off the GE website. If you call Syracuse, ask for
> Phil Gordon, and Lexan film 8010-112.
>
>
--- Inbolger@yahoogroups.com, Rick <sctree@d...> wrote:
Indeed, but at the size suggested here, you are already in the"I'll
need a gang to move this" category so a bit more weight just means
more hands.
This is good to consider since you will/can certainly be intimidated
by the size of the assembled panels. Stressing yourself out further
may not ensure there are no mistakes.
The idea with the polyester film is sound...it is perhaps more a
question of practicality for a solo builder.Also it should be kept
in mind what level of finish and construction you are aiming for or
can accomplish.It would be odd to have a perfectly smooth"mirror"
surface outside only to find poorly fitted butt joints made from
recycled 2X4's on the inside...........
Of course I am also not suggesting to you Garth that your work is
anything less then perfect.Instead, a clear consistant vision of how
you want your boat done is needed before going this route,otherwise
the effort of getting the incredible surface may be lost if;a)it is
on the bottom and always underwater,b) you WANT a simple/low
maintainence boat and c) it serves to "drive" the rest of the work
and consumes so much time going for perfection EVERYWHERE that you
take up full time drinking,forget all about launch dates and why you
are building this boat and simply lose your mind.
Ricks observations(above) and concerns are more elements to consider.
I'd reserve this building technique for small dinghys or for the day
I inherit buckets of cash to pay for the indoor-heated-staffed-every-
tool-under-the-sun workshop which sometimes pops up in my dreams.
keep us posted on your findings/results!!
Sincerely,
Peter Lenihan,encouraged by all the big boat building looming on the
horizon
> Pre-glassing the full sized panels will add extra weight to thealready heavy panels.
Indeed, but at the size suggested here, you are already in the"I'll
need a gang to move this" category so a bit more weight just means
more hands.
> The filming and rolling will add a pair of time sensitiveprocesses to the glassing.
This is good to consider since you will/can certainly be intimidated
by the size of the assembled panels. Stressing yourself out further
may not ensure there are no mistakes.
> The nearly perfect glassed/filmed/rolled panels are likely tosuffer some damage during
> handling (at least by me).and by me too!
> There will still be the holes from temporary alignment screws andany alignment wiring ties
> that will need fillingYou betcha and more then few to boot........
> The taped seams will have to be faired into those "mirror finish"filmed/rolled panels. I
> imagine you could film/roll the tape, but I think they will stillneed filler to fair the
> seams into the preglassed area.Sounds like a recipe for maddness :-)
The idea with the polyester film is sound...it is perhaps more a
question of practicality for a solo builder.Also it should be kept
in mind what level of finish and construction you are aiming for or
can accomplish.It would be odd to have a perfectly smooth"mirror"
surface outside only to find poorly fitted butt joints made from
recycled 2X4's on the inside...........
Of course I am also not suggesting to you Garth that your work is
anything less then perfect.Instead, a clear consistant vision of how
you want your boat done is needed before going this route,otherwise
the effort of getting the incredible surface may be lost if;a)it is
on the bottom and always underwater,b) you WANT a simple/low
maintainence boat and c) it serves to "drive" the rest of the work
and consumes so much time going for perfection EVERYWHERE that you
take up full time drinking,forget all about launch dates and why you
are building this boat and simply lose your mind.
Ricks observations(above) and concerns are more elements to consider.
I'd reserve this building technique for small dinghys or for the day
I inherit buckets of cash to pay for the indoor-heated-staffed-every-
tool-under-the-sun workshop which sometimes pops up in my dreams.
keep us posted on your findings/results!!
Sincerely,
Peter Lenihan,encouraged by all the big boat building looming on the
horizon
To combine a couple of recent threads, I ordered a roll of 20 mil
Lexan film today from GE Polymershapes (www.gepolymershapes.com/).
It's 48" wide by 40' long. It cost $1.04 per sq. foot. Sounds a bit
crazy for a process I haven't tested yet, but I'll take the gamble on
John Blazy's say-so. I'm impatient to get going on my project before
cold weather cuts it off.
I'm about to start laying out the panels for my Michalak Cormorant
(31' trailer-sailer). Basically two very big sidepanels, nearly 4' at
widest section by 32' long; two slimmer bilge panels, also about 32'
long, and one humongous bottom panel, about 5'6" at its widest by 20'
long. I'm going to preglass them all -- and if this polyester film
technique works, they'll take less epoxy and have a smoother finish,
saving much sanding time.
With any luck this film will hold up for future boats. Of course,
I'll have to build many more boats to amortize the extravagant cost
of the film.
I'll report soon, I hope.
All best,
Garth
PS I ordered from the Syracuse, NY branch -- 315-422-9165. You can
also order right off the GE website. If you call Syracuse, ask for
Phil Gordon, and Lexan film 8010-112.
Lexan film today from GE Polymershapes (www.gepolymershapes.com/).
It's 48" wide by 40' long. It cost $1.04 per sq. foot. Sounds a bit
crazy for a process I haven't tested yet, but I'll take the gamble on
John Blazy's say-so. I'm impatient to get going on my project before
cold weather cuts it off.
I'm about to start laying out the panels for my Michalak Cormorant
(31' trailer-sailer). Basically two very big sidepanels, nearly 4' at
widest section by 32' long; two slimmer bilge panels, also about 32'
long, and one humongous bottom panel, about 5'6" at its widest by 20'
long. I'm going to preglass them all -- and if this polyester film
technique works, they'll take less epoxy and have a smoother finish,
saving much sanding time.
With any luck this film will hold up for future boats. Of course,
I'll have to build many more boats to amortize the extravagant cost
of the film.
I'll report soon, I hope.
All best,
Garth
PS I ordered from the Syracuse, NY branch -- 315-422-9165. You can
also order right off the GE website. If you call Syracuse, ask for
Phil Gordon, and Lexan film 8010-112.