Re: Bolger imitation
--- Inbolger@yahoogroups.com, "John Bell" <smallboatdesigner@m...>
wrote:
I took a closer look at the lines of the boat in question and
realised that this box-keel is indeed deeper and,more
importantly,extends all the way aft in a fine cigar shape. Not at all
like the Windermere whose box keel only extends aft for about 16 feet
before becoming a shoe.I guess hulls built with a more significant
box-keel would do well to have a minimum of top hamper for
stabilities sake,as you correctly noted. :-)
Sincerely,
Peter Lenihan
wrote:
> Agreed that its a good place to store heavy stuff, but all thatvolume way
> down low on these boats will still contribute to lowering thecenter of
> buoyancy, which is bad for ultimate stability.one that
>
> Bolger actually designed a very similar steel hulled boat to this
> he discussed in a recent MAIB. He also mentions the stabilitypenalty for
> the hull type.deeper
>
> A boat like your Windermere has a box keel, but it's not three feet
> than the sponsons like on this boat! So you won't incur the loss ofHi John,
> stability from having all that volume way down under the water.
I took a closer look at the lines of the boat in question and
realised that this box-keel is indeed deeper and,more
importantly,extends all the way aft in a fine cigar shape. Not at all
like the Windermere whose box keel only extends aft for about 16 feet
before becoming a shoe.I guess hulls built with a more significant
box-keel would do well to have a minimum of top hamper for
stabilities sake,as you correctly noted. :-)
Sincerely,
Peter Lenihan
--- Inbolger@yahoogroups.com, Jim Pope <jpope@a...> wrote:
I do agree whole heartedly with you that the box keel structure
and fairing pieces serve a much great purpose then mere storage.I
recall that as the pieces were installed,I found myself hypnotized by
the incredible elegance of flowing curves.The water is going to like
this bottom very very much:-)
Certainly,there is science behind this hydro-dynamic flow and the
boat will greatly benefit from its presence.Otherwise,without the box-
keel and fillet pieces,one is left with nothing more then a pointy
nosed garvey hull AND scant volume up forward to support meaningful
weights.
Recently,I had the pleasure of meeting with another Bolger group
member who happens to live near by and is building a Champlain. I
noticed on the plans for the Champlain that Bolger is now offering a
fillet/fairing piece for this design too.The interesting
thing,however,is that the fillet piece for the Champlain appears to
be no more then a wedge shaped addition to fair out somewhat the
harshness of the right angle caused by the box-keel whereas on
Windermere,the fillet piece is really a developed surface with
delicious curves happening in both planes.
It is interesting to follow where Bolgers thinking is going with
developable surfaces,especially regarding the refinement of hull
entrances.
I can't tell you how eager I am to play in the run-off of the
Great Lakes and to take her down to Lake Champlain one fine summer!!
Sincerely,
Peter Lenihan,finally dug out from a few too many
snowflakes.....gotta be more careful with what I wish for,I guess!!!
> > That's convenient, Peter, but Oh Boy, that structure sure hasanother
> > use, one that just happens every time the vessel moves throughthe
> > water. I don't know whether those lovely fairing pieces you'veadded
> > under your icebox creation up there where the good days get up to20
> > deg. below freezing will add or detract from the blunt unfairedtake
> > effect. You'll be able to tell, pretty quick I guess, once you
> > her out onto the Great lakes runoff.Hi Jim,
>
>
> All the best,
> Jim
I do agree whole heartedly with you that the box keel structure
and fairing pieces serve a much great purpose then mere storage.I
recall that as the pieces were installed,I found myself hypnotized by
the incredible elegance of flowing curves.The water is going to like
this bottom very very much:-)
Certainly,there is science behind this hydro-dynamic flow and the
boat will greatly benefit from its presence.Otherwise,without the box-
keel and fillet pieces,one is left with nothing more then a pointy
nosed garvey hull AND scant volume up forward to support meaningful
weights.
Recently,I had the pleasure of meeting with another Bolger group
member who happens to live near by and is building a Champlain. I
noticed on the plans for the Champlain that Bolger is now offering a
fillet/fairing piece for this design too.The interesting
thing,however,is that the fillet piece for the Champlain appears to
be no more then a wedge shaped addition to fair out somewhat the
harshness of the right angle caused by the box-keel whereas on
Windermere,the fillet piece is really a developed surface with
delicious curves happening in both planes.
It is interesting to follow where Bolgers thinking is going with
developable surfaces,especially regarding the refinement of hull
entrances.
I can't tell you how eager I am to play in the run-off of the
Great Lakes and to take her down to Lake Champlain one fine summer!!
Sincerely,
Peter Lenihan,finally dug out from a few too many
snowflakes.....gotta be more careful with what I wish for,I guess!!!
Actually, I'm looking at the plans for the Chebacco which show openings to
the hollow portions of the external keel. Perhaps Chebacco's keel is not
what you're referring to?
The only other image that comes to mind is the box on the bow of some PCB's
designs, but adding weight to the ends would seem poor practice. Are these
accessible from inboard?
Roger
derbyrm@...
http://derbyrm.mystarband.net
the hollow portions of the external keel. Perhaps Chebacco's keel is not
what you're referring to?
The only other image that comes to mind is the box on the bow of some PCB's
designs, but adding weight to the ends would seem poor practice. Are these
accessible from inboard?
Roger
derbyrm@...
http://derbyrm.mystarband.net
----- Original Message -----
From: "Peter Lenihan" <lestat@...>
> --- Inbolger@yahoogroups.com, "Roger Derby" <derbyrm@s...> wrote:
> > I thought Bolger's box keels were open to the sea so the water
> filling them
> > would add to their moment.
>
> Roger,
>
> You may be thinking about the free-flooding chambers Bolger
> sometimes uses for ballast effect,like in the deadwood areas of the
> Micro etc...
> The box-keel proper,is completely water tight and depending on
> the size of the boat,can/is used for storage space.
Agreed that its a good place to store heavy stuff, but all that volume way
down low on these boats will still contribute to lowering the center of
buoyancy, which is bad for ultimate stability.
Bolger actually designed a very similar steel hulled boat to this one that
he discussed in a recent MAIB. He also mentions the stability penalty for
the hull type.
A boat like your Windermere has a box keel, but it's not three feet deeper
than the sponsons like on this boat! So you won't incur the loss of
stability from having all that volume way down under the water.
down low on these boats will still contribute to lowering the center of
buoyancy, which is bad for ultimate stability.
Bolger actually designed a very similar steel hulled boat to this one that
he discussed in a recent MAIB. He also mentions the stability penalty for
the hull type.
A boat like your Windermere has a box keel, but it's not three feet deeper
than the sponsons like on this boat! So you won't incur the loss of
stability from having all that volume way down under the water.
----- Original Message -----
From: "Peter Lenihan" <lestat@...>
To: <bolger@yahoogroups.com>
Sent: Monday, December 15, 2003 6:12 PM
Subject: [bolger] Re: Bolger imitation
| --- Inbolger@yahoogroups.com, "John Bell" <smallboatdesigner@m...>
| wrote:
| > It departs from Bolger in a couple of significant ways. The biggest
| > departure is that the central box is a LOT deeper than most of
| > Bolgers step sharpie designs. This means deeper draft. All that
| > buoyancy down low has also to mean bad things for stability. I
| would
| > not want to be caught out in bad weather in a boat like that one.
|
| Hi John,
| The cavity formed by the box-keel can also serve as a wonderful
| place,out from under your feet,to locate most of the significant
| weights like fuel,anchor chain,batteries,waste etc...not to mention
| ballast.So,although the box keel appears to bring some"bouyancy" in
| the wrong part of the hull,this effect may be cancelled if used as a
| ballast chamber.
|
| Sincerely,
|
| Peter Lenihan
|
|
|
| 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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|
Philip C. Bolger is a modest and unassuming man. In a conversation in
his house in Gloucester over five or six years ago I pointed out to him
that I thought he had found a unique and very interesting hull form that
would help to limit wave drag with his Micro trawler and similar hulls.
He certainly knew that the box keel assumes much of the boat's
displacement but he didn't take much credit for the remainder of the
hull form actively suppressing the formation of the energy stealing
waves. It does.
That combination is what the German group has apparently managed to get
a patent on claiming the revolutionary nature of the invention. If he
were the kind of person who wanted to make a fight of it, I think that
he would have a pretty good case. He isn't though, and I think that we
have all profited by his generosity of spirit.
Jim Pope
Peter Lenihan wrote:
Jim
his house in Gloucester over five or six years ago I pointed out to him
that I thought he had found a unique and very interesting hull form that
would help to limit wave drag with his Micro trawler and similar hulls.
He certainly knew that the box keel assumes much of the boat's
displacement but he didn't take much credit for the remainder of the
hull form actively suppressing the formation of the energy stealing
waves. It does.
That combination is what the German group has apparently managed to get
a patent on claiming the revolutionary nature of the invention. If he
were the kind of person who wanted to make a fight of it, I think that
he would have a pretty good case. He isn't though, and I think that we
have all profited by his generosity of spirit.
Jim Pope
Peter Lenihan wrote:
> The box-keel proper,is completely water tight and depending onAll the best,
> the size of the boat,can/is used for storage space.
>
> That's convenient, Peter, but Oh Boy, that structure sure has another
> use, one that just happens every time the vessel moves through the
> water. I don't know whether those lovely fairing pieces you've added
> under your icebox creation up there where the good days get up to 20
> deg. below freezing will add or detract from the blunt unfaired
> effect. You'll be able to tell, pretty quick I guess, once you take
> her out onto the Great lakes runoff.
Jim
--- Inbolger@yahoogroups.com, "Roger Derby" <derbyrm@s...> wrote:
You may be thinking about the free-flooding chambers Bolger
sometimes uses for ballast effect,like in the deadwood areas of the
Micro etc...
The box-keel proper,is completely water tight and depending on
the size of the boat,can/is used for storage space.
Sincerely,
Peter Lenihan
> I thought Bolger's box keels were open to the sea so the waterfilling them
> would add to their moment.Roger,
>
> Roger
> derbyrm@s...
>http://derbyrm.mystarband.net
You may be thinking about the free-flooding chambers Bolger
sometimes uses for ballast effect,like in the deadwood areas of the
Micro etc...
The box-keel proper,is completely water tight and depending on
the size of the boat,can/is used for storage space.
Sincerely,
Peter Lenihan
--- Inbolger@yahoogroups.com, "John Bell" <smallboatdesigner@m...>
wrote:
The cavity formed by the box-keel can also serve as a wonderful
place,out from under your feet,to locate most of the significant
weights like fuel,anchor chain,batteries,waste etc...not to mention
ballast.So,although the box keel appears to bring some"bouyancy" in
the wrong part of the hull,this effect may be cancelled if used as a
ballast chamber.
Sincerely,
Peter Lenihan
wrote:
> It departs from Bolger in a couple of significant ways. The biggestwould
> departure is that the central box is a LOT deeper than most of
> Bolgers step sharpie designs. This means deeper draft. All that
> buoyancy down low has also to mean bad things for stability. I
> not want to be caught out in bad weather in a boat like that one.Hi John,
The cavity formed by the box-keel can also serve as a wonderful
place,out from under your feet,to locate most of the significant
weights like fuel,anchor chain,batteries,waste etc...not to mention
ballast.So,although the box keel appears to bring some"bouyancy" in
the wrong part of the hull,this effect may be cancelled if used as a
ballast chamber.
Sincerely,
Peter Lenihan
I thought Bolger's box keels were open to the sea so the water filling them
would add to their moment.
Roger
derbyrm@...
http://derbyrm.mystarband.net
would add to their moment.
Roger
derbyrm@...
http://derbyrm.mystarband.net
----- Original Message -----
From: "John Bell" <smallboatdesigner@...>
> It departs from Bolger in a couple of significant ways. The biggest
> departure is that the central box is a LOT deeper than most of
> Bolgers step sharpie designs. This means deeper draft. All that
> buoyancy down low has also to mean bad things for stability. I would
> not want to be caught out in bad weather in a boat like that one.
>> "Look at the lines shown in the backgroud of the press release page...."Saved with the lines darkened for easier viewing as zeichnung.gif in Bolger3
files.
cheers
Derk
It departs from Bolger in a couple of significant ways. The biggest
departure is that the central box is a LOT deeper than most of
Bolgers step sharpie designs. This means deeper draft. All that
buoyancy down low has also to mean bad things for stability. I would
not want to be caught out in bad weather in a boat like that one.
departure is that the central box is a LOT deeper than most of
Bolgers step sharpie designs. This means deeper draft. All that
buoyancy down low has also to mean bad things for stability. I would
not want to be caught out in bad weather in a boat like that one.
> --- "pep cruells" wrote:
> > Yessir, it's a copy.
>
> I think it is similar but
> not a copy.
>
> Look at the lines shown in
> the backgroud of the
> press release page.
>
>http://www.alsphere.at/press/index.php
>
> Bolger's cutwaters and box keels
> have a vertical sides, and the
> Altspere has sloping sides.
>
> Also, the fore to aft shape is a
> segment of a circle, where Bolger
> has straight runs in the center.
>
> I don't have the expertise to
> judge which version works best
> but my bet is on Phil Bolger.
--- "pep cruells" wrote:
not a copy.
Look at the lines shown in
the backgroud of the
press release page.
http://www.alsphere.at/press/index.php
Bolger's cutwaters and box keels
have a vertical sides, and the
Altspere has sloping sides.
Also, the fore to aft shape is a
segment of a circle, where Bolger
has straight runs in the center.
I don't have the expertise to
judge which version works best
but my bet is on Phil Bolger.
> Yessir, it's a copy.I think it is similar but
not a copy.
Look at the lines shown in
the backgroud of the
press release page.
http://www.alsphere.at/press/index.php
Bolger's cutwaters and box keels
have a vertical sides, and the
Altspere has sloping sides.
Also, the fore to aft shape is a
segment of a circle, where Bolger
has straight runs in the center.
I don't have the expertise to
judge which version works best
but my bet is on Phil Bolger.
Yep,
I think a little bit of Atkins seabrite hull too. Not to new, but
good to see a new design based on the box keel idea, I think.
dick
--- Inbolger@yahoogroups.com, "pererieravicens" <flexitub@s...>
wrote:
I think a little bit of Atkins seabrite hull too. Not to new, but
good to see a new design based on the box keel idea, I think.
dick
--- Inbolger@yahoogroups.com, "pererieravicens" <flexitub@s...>
wrote:
> Is not a copy the patented design DISPLACEMENT GLIDER ?
> Seen in BOATBUILDER Nº86 December page 24 and in www.alsphere.at
> Pere
In Catalan: Si senyor, es una copia.
In English: Yessir, it's a copy.
What a Shame! Lets flood alsphere.at with emails!
pep
--- Inbolger@yahoogroups.com, "pererieravicens" <flexitub@s...>
wrote:
In English: Yessir, it's a copy.
What a Shame! Lets flood alsphere.at with emails!
pep
--- Inbolger@yahoogroups.com, "pererieravicens" <flexitub@s...>
wrote:
> Is not a copy the patented design DISPLACEMENT GLIDER ?
> Seen in BOATBUILDER Nº86 December page 24 and in www.alsphere.at
> Pere
Is not a copy the patented design DISPLACEMENT GLIDER ?
Seen in BOATBUILDER Nº86 December page 24 and in www.alsphere.at
Pere
Seen in BOATBUILDER Nº86 December page 24 and in www.alsphere.at
Pere