Re: [bolger] Re: Commonsense Skiff
James,
The boatbuilding foams like Airex, Corecell and Divinicell are more dense
than styrofoam. 5 to 8 lbs per cubic ft. compared to 1.1 (white) to 2
(pink or blue). The lighter the foam the thicker the skin needs to be to
maintain the bond when struck. I've built two boats from blue foam, a tri
that didn't last very long made of 1" thick foam with glass/epoxy skins,
and a solid foam paddleboard I still have. The board has two layers of 6
oz glass in epoxy resin on the bottom and a 3mm ply deck. The two layers of
6 are about minimum I think, and it is still easily punctured or dented. It
just doesn't matter much if it is, as it still floats, being solid foam. If
you are always building boats with epoxy anyway, you fill the dings easily.
The ply deck seems to take a lot of abuse without delaminating though, and
could make a good boat with 1" foam inside 3mm ply with glass inside, but
would probably weigh as much as 1/4" ply. I like using the blue foam though
and still use it for things like outrigger floats or sponsons, i.e. solid
foam objects with glass skin, rather than as a foam sandwich hull skin .
Gary Lepak
The boatbuilding foams like Airex, Corecell and Divinicell are more dense
than styrofoam. 5 to 8 lbs per cubic ft. compared to 1.1 (white) to 2
(pink or blue). The lighter the foam the thicker the skin needs to be to
maintain the bond when struck. I've built two boats from blue foam, a tri
that didn't last very long made of 1" thick foam with glass/epoxy skins,
and a solid foam paddleboard I still have. The board has two layers of 6
oz glass in epoxy resin on the bottom and a 3mm ply deck. The two layers of
6 are about minimum I think, and it is still easily punctured or dented. It
just doesn't matter much if it is, as it still floats, being solid foam. If
you are always building boats with epoxy anyway, you fill the dings easily.
The ply deck seems to take a lot of abuse without delaminating though, and
could make a good boat with 1" foam inside 3mm ply with glass inside, but
would probably weigh as much as 1/4" ply. I like using the blue foam though
and still use it for things like outrigger floats or sponsons, i.e. solid
foam objects with glass skin, rather than as a foam sandwich hull skin .
Gary Lepak
----- Original Message ----- > I wonder if the cheapest available foam might
not be "good enough" for
> most small boats, provided it fills the void between the inner and
> outer skins and does not separate from them. Does this leave out good
> old fashioned styrofoam I wonder?
>
> James Greene
--- Inbolger@yahoogroups.com, Chris Lasdauskas <cml@t...> wrote:
Consider skin on frame constuction using 26 ounce double ply woven
nylon skin. Quoting from "UMIAK An Illustrated Guide" by Skip Snaith:
"The 26-ounce double-weave nylon skin on Tim's boat was incredibly
tough; you could hit it with the claw end of a hammer as hard as you
liked, and the hammer would bounce back."
Skin on frame can produce very light boats. Platt Monfort's Geodesic
Aerolight boats are incredibly light, but probably not strong enough
for the Watertribe Challenge. Up the scantlings a bit, with the frame
lashed rather than glued to preserve flexibility, and use a much
tougher skin and you'd end up with a light, resilient boat.
Chris Stewart
> 'To demonstrate his point, the builder took a hammer and wacked atthe
> sample panel mightily. With the hammer bouncing off harmlessly, heat
> offered it confidently to the skeptical architect. Taking the hammer,
> the architect turned it claw-side down and - with virtually no force
> all - drove it right through Kevlar, the foam, and out the otherside.
Consider skin on frame constuction using 26 ounce double ply woven
nylon skin. Quoting from "UMIAK An Illustrated Guide" by Skip Snaith:
"The 26-ounce double-weave nylon skin on Tim's boat was incredibly
tough; you could hit it with the claw end of a hammer as hard as you
liked, and the hammer would bounce back."
Skin on frame can produce very light boats. Platt Monfort's Geodesic
Aerolight boats are incredibly light, but probably not strong enough
for the Watertribe Challenge. Up the scantlings a bit, with the frame
lashed rather than glued to preserve flexibility, and use a much
tougher skin and you'd end up with a light, resilient boat.
Chris Stewart
I think I used inch and a half foam for my Brick and had to use a lot of
glass and epoxy to get strength to stand in. I also made a deck of sorts
from 1/4 ply so the sides wouldn't bolge out. Overall, not worth the
money in glass and epoxy, and the trouble. If you do go forward, I would
think a multi
chine rather than large flat areas like the bottom of a Brick. My foam
Brick floats upside down of course and almost floated away during
Isabell, which might not have been bad. Clyde.
James Greene wrote:
glass and epoxy to get strength to stand in. I also made a deck of sorts
from 1/4 ply so the sides wouldn't bolge out. Overall, not worth the
money in glass and epoxy, and the trouble. If you do go forward, I would
think a multi
chine rather than large flat areas like the bottom of a Brick. My foam
Brick floats upside down of course and almost floated away during
Isabell, which might not have been bad. Clyde.
James Greene wrote:
> > These days I would use Corefoam,[Non-text portions of this message have been removed]
> > though it is expensive.
>
> I wonder if the cheapest available foam might not be "good enough" for
> most small boats, provided it fills the void between the inner and
> outer skins and does not separate from them. Does this leave out good
> old fashioned styrofoam I wonder?
>
> James Greene
>
>
>
>
>
>
> Bolger rules!!!
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> These days I would use Corefoam,I wonder if the cheapest available foam might not be "good enough" for
> though it is expensive.
most small boats, provided it fills the void between the inner and
outer skins and does not separate from them. Does this leave out good
old fashioned styrofoam I wonder?
James Greene
Wow, when I was thinking abut glass over foam construction I was
considering 1 inch foam or thicker for the hulls. You guys are using
foam that's less than half this thickness! Interesting ...
James Greene
considering 1 inch foam or thicker for the hulls. You guys are using
foam that's less than half this thickness! Interesting ...
James Greene
On Jul 3, 2005, at 09:58, gbship wrote:
> A friend
> laminated a couple layers of glass on either side of 3/8 inch foam (I
> think that was the thickness) and you could whack it with a hammer
> without damage and it was considerably lighter than a ply sandwich
> would have been. I made some hatches for our Frolic2 of glass over 1/4-
> inch foam and those are reasonably strong, and very light, but not
> strong enough for use for a hull.
Perhaps *the* small boat team time trial endurance event.
--- Inbolger@yahoogroups.com, "Howard Stephenson" <stephensonhw@a...>
wrote:
--- Inbolger@yahoogroups.com, "Howard Stephenson" <stephensonhw@a...>
wrote:
> To see a boat that is suitable for South Georgia, go to:
>
>http://www.ibiblio.org/ebooks/Shackleton/South/057.jpg
>
> Howard ;-]
>
> --- Inbolger@yahoogroups.com, "gbship" <gbship@c...> wrote:
>
> > so at one point, competitors have to go up the St. Mary's
> > river (in S. Georgia) and then portage their boats 40 MILES
To see a boat that is suitable for South Georgia, go to:
http://www.ibiblio.org/ebooks/Shackleton/South/057.jpg
Howard ;-]
http://www.ibiblio.org/ebooks/Shackleton/South/057.jpg
Howard ;-]
--- Inbolger@yahoogroups.com, "gbship" <gbship@c...> wrote:
> so at one point, competitors have to go up the St. Mary's
> river (in S. Georgia) and then portage their boats 40 MILES
Gary,
For what it's worth, I once built a Bolger Dolphin, (Small Boats, Design
#259, 18' x 4') out of 3/8" Airex foam with two layers of 6 oz glass inside
and out. It was a stripped down rowboat version, no centerboard, rudder or
rig. It weighed about a 100 lbs. I never weighed it, but two people could
throw it over their heads like a canoe. It seemed quite tough, and I never
worried about punctures or breakage. Of course it is a compound curved
hull so the bulding took some time with lofting and moldmaking, but you
would get a strong light hull this way. These days I would use Corefoam,
though it is expensive.
For a cheaper light boat that would be quicker to build I might try
lapstrake plywood. You could vary the plank thickness, say 4 to 5 mm on the
bottom and 3mm topsides.
Gary Lepak
Port Angeles, WA
For what it's worth, I once built a Bolger Dolphin, (Small Boats, Design
#259, 18' x 4') out of 3/8" Airex foam with two layers of 6 oz glass inside
and out. It was a stripped down rowboat version, no centerboard, rudder or
rig. It weighed about a 100 lbs. I never weighed it, but two people could
throw it over their heads like a canoe. It seemed quite tough, and I never
worried about punctures or breakage. Of course it is a compound curved
hull so the bulding took some time with lofting and moldmaking, but you
would get a strong light hull this way. These days I would use Corefoam,
though it is expensive.
For a cheaper light boat that would be quicker to build I might try
lapstrake plywood. You could vary the plank thickness, say 4 to 5 mm on the
bottom and 3mm topsides.
Gary Lepak
Port Angeles, WA
There have been various threads wich suggest that PCB doesn't design
"racing" boats. You might take a look at Paul Gartside's web site--His
Flashboat is a very light, very fast row boat and he has camp cruised around
Alaska in it.
It appears to me that the rules you described favor a kayak with a sail.
I've always thought that a two person rowing boat would do well in this sort
of race--the two rowers could alternate and maintain speed more or less
continuously; they would also have the ability to row together and buck
currents if needed.
I'm way too old and decrepit to participate or even enjoy the kind of boat
needed for this kind of event, but iy si fun to think about.
John T
"racing" boats. You might take a look at Paul Gartside's web site--His
Flashboat is a very light, very fast row boat and he has camp cruised around
Alaska in it.
It appears to me that the rules you described favor a kayak with a sail.
I've always thought that a two person rowing boat would do well in this sort
of race--the two rowers could alternate and maintain speed more or less
continuously; they would also have the ability to row together and buck
currents if needed.
I'm way too old and decrepit to participate or even enjoy the kind of boat
needed for this kind of event, but iy si fun to think about.
John T
----- Original Message -----
From: "gbship" <gbship@...>
To: <bolger@yahoogroups.com>
Sent: Sunday, July 03, 2005 7:57 AM
Subject: [bolger] Re: Commonsense Skiff
> >
> > That's what I was talking about when I mentioned penetration
> strength.
> > Sure a Gypsy isn't going to hit logs at 30 knots, but the scantlings
> > will already be redeuced in proportion to the speed. You can't let
> the
> > skins get too thin. 'Too thin' on foam is thinnner than 'too thin' on
> > ply. Avoiding that was where the extra weight came from.
> >
> > Chris
>
> Thanks everyone for the thought and advice. I should have explained
> better the use for this boat. It's for an expedition type competition
> of around 1,000 miles, give or take, for kayaks and small sailboats.
> Among the salient features, are you must beach launch your craft (You
> can use mechanical assistance, but you must carry whatever you use for
> the entire race), the ability to go under a 9-foot high bridge with 10-
> foot horizontal clearance, deal with open water and inland waterways
> churned by powerboat wakes, etc. This race is around the peninsula part
> of Florida, so at one point, competitors have to go up the St. Mary's
> river (in S. Georgia) and then portage their boats 40 MILES to the
> Suwanee. The kayakers balance their boats on a set of wheels, attach
> the bow to the back of their belt and walk it. They can also tow it
> with a folding bike -- as long as they carry the bike for the entire
> race. Obviously this won't work for sailboats, which even in a small
> size weigh much more. So those comeptitors are allowed to switch to a
> canoe for the necessary river portions and the portage. You can see the
> details at Watertribe.com, check the Ultra Florida Challenge section.
> We're only planning to do the shorter Everglades Challenge in 2006, in
> our Frolic2, but I'm intrigued with trying the longer race in 2007. My
> particular itch right now is to wonder if a small sailboat could be
> built light enough so that switching to the canoe would be unnecessary,
> even for the portage (which I would do with a bike!).
>
> But, alas, I know almost nothing of composite construction, which is
> why everyone's advice is so helpful and much appreciated. It does no
> good to have an ultralight hull if it's punctured by a razor sharp
> shell on an oyster bar, or a cypress knee or mangrove root in the
> Everglades, or by a rock or log in the Suwanee. The weight concern is
> why I've been mostly looking at ply instant-type boats in the 125 to
> 150 pound range and wondering if that weight could be cut in half with
> composite construction. There are intriguing hints. For example, my 25-
> 30 pound solid wood mast on the Rolic2 could be replaced by a carbon
> fiber spar that would weight less than 10 pounds. In Pete Goss' book
> about single handed racing around the world, he mentions that the bare
> hull of his 50 footer could be turned over by 6 husky guys --- about
> what the 1/2 inch ply/fiberglass bare hull weighs on our 30-footer
> (which is a Gypsy-type hull).
>
> BTW Graeme, thanks for the suggestion of the Zephyr, but I ruled that
> out because while it is an excellent daysailer and can handle some
> nasty weather, it doesn't row very well, possibly because the 16-inch
> sides are too high. (I had one for many years, and was very fond of it.)
>
> Gary Blankenship
>
>
>
>
> Bolger rules!!!
> - no cursing, flaming, trolling, spamming, or flogging dead horses
> - stay on topic, stay on thread, punctuate, no 'Ed, thanks, Fred' posts
> - Pls add your comments at the TOP, SIGN your posts, and snip away
> - Plans: Mr. Philip C. Bolger, P.O. Box 1209, Gloucester, MA, 01930, Fax:
(978) 282-1349
> - Unsubscribe:bolger-unsubscribe@yahoogroups.com
> - Open discussion:bolger_coffee_lounge-subscribe@yahoogroups.com
> Yahoo! Groups Links
>
>
>
>
>
>
>
>
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>
>strength.
> That's what I was talking about when I mentioned penetration
> Sure a Gypsy isn't going to hit logs at 30 knots, but the scantlingsthe
> will already be redeuced in proportion to the speed. You can't let
> skins get too thin. 'Too thin' on foam is thinnner than 'too thin' onThanks everyone for the thought and advice. I should have explained
> ply. Avoiding that was where the extra weight came from.
>
> Chris
better the use for this boat. It's for an expedition type competition
of around 1,000 miles, give or take, for kayaks and small sailboats.
Among the salient features, are you must beach launch your craft (You
can use mechanical assistance, but you must carry whatever you use for
the entire race), the ability to go under a 9-foot high bridge with 10-
foot horizontal clearance, deal with open water and inland waterways
churned by powerboat wakes, etc. This race is around the peninsula part
of Florida, so at one point, competitors have to go up the St. Mary's
river (in S. Georgia) and then portage their boats 40 MILES to the
Suwanee. The kayakers balance their boats on a set of wheels, attach
the bow to the back of their belt and walk it. They can also tow it
with a folding bike -- as long as they carry the bike for the entire
race. Obviously this won't work for sailboats, which even in a small
size weigh much more. So those comeptitors are allowed to switch to a
canoe for the necessary river portions and the portage. You can see the
details at Watertribe.com, check the Ultra Florida Challenge section.
We're only planning to do the shorter Everglades Challenge in 2006, in
our Frolic2, but I'm intrigued with trying the longer race in 2007. My
particular itch right now is to wonder if a small sailboat could be
built light enough so that switching to the canoe would be unnecessary,
even for the portage (which I would do with a bike!).
But, alas, I know almost nothing of composite construction, which is
why everyone's advice is so helpful and much appreciated. It does no
good to have an ultralight hull if it's punctured by a razor sharp
shell on an oyster bar, or a cypress knee or mangrove root in the
Everglades, or by a rock or log in the Suwanee. The weight concern is
why I've been mostly looking at ply instant-type boats in the 125 to
150 pound range and wondering if that weight could be cut in half with
composite construction. There are intriguing hints. For example, my 25-
30 pound solid wood mast on the Rolic2 could be replaced by a carbon
fiber spar that would weight less than 10 pounds. In Pete Goss' book
about single handed racing around the world, he mentions that the bare
hull of his 50 footer could be turned over by 6 husky guys --- about
what the 1/2 inch ply/fiberglass bare hull weighs on our 30-footer
(which is a Gypsy-type hull).
BTW Graeme, thanks for the suggestion of the Zephyr, but I ruled that
out because while it is an excellent daysailer and can handle some
nasty weather, it doesn't row very well, possibly because the 16-inch
sides are too high. (I had one for many years, and was very fond of it.)
Gary Blankenship
gbship wrote:
think I used "The Elements of Boat Strength for Builders, Designers, and
Owners" by Dave Gerr (though that is copyright 2000, and I thought I did
this in about 1999..., perhaps I used his "The Nature of Boats"), I
think I also didn't find much online.
'A Warning About Being Thin-Skinned
'A final word of warning is in order. When using these high-strength
fibers and sandwich construction, the skin thickness required for
overall —- remember overall -— structural strength can become almost
unbelievably thin, even on quite large vessels. This works out well on
paper, but what about hitting a floating log? A well-known designer
related a story both amusing and worrisome. A local builder of large
(90-foot, 27-meter) high-speed sportfishermen proudly showed him an
all-Kevlar, foam-sandwich hull panel that he'd used in a couple of
recent craft. The builder explained that his computer confirmed the
very, very thin skins (on the inside and outside of the foam) were more
than up to the job.
'To demonstrate his point, the builder took a hammer and wacked at the
sample panel mightily. With the hammer bouncing off harmlessly, he
offered it confidently to the skeptical architect. Taking the hammer,
the architect turned it claw-side down and -— with virtually no force at
all -— drove it right through Kevlar, the foam, and out the other side.
The builder's face turned white. He had a couple of boats out on the
water with this layup. The moral -— there's always a moral -— is that
the structural design of high-tech hulls is a complicated business.
Before you dash off to build or have built one of these miracle hulls,
make sure a good naval architect does a detailed structural analysis.'
That's what I was talking about when I mentioned penetration strength.
Sure a Gypsy isn't going to hit logs at 30 knots, but the scantlings
will already be redeuced in proportion to the speed. You can't let the
skins get too thin. 'Too thin' on foam is thinnner than 'too thin' on
ply. Avoiding that was where the extra weight came from.
Chris
>Gary, as I said it was a few years back, so this may not be right, but I
> Chris: How do you figure scantlings for foam/glass construction? I've
> done some online looking, but haven't found any resources.
think I used "The Elements of Boat Strength for Builders, Designers, and
Owners" by Dave Gerr (though that is copyright 2000, and I thought I did
this in about 1999..., perhaps I used his "The Nature of Boats"), I
think I also didn't find much online.
> A friendWhich reminds me of this cautionary story from "The Nature of Boats":
> laminated a couple layers of glass on either side of 3/8 inch foam (I
> think that was the thickness) and you could whack it with a hammer
> without damage and it was considerably lighter than a ply sandwich
> would have been.
'A Warning About Being Thin-Skinned
'A final word of warning is in order. When using these high-strength
fibers and sandwich construction, the skin thickness required for
overall —- remember overall -— structural strength can become almost
unbelievably thin, even on quite large vessels. This works out well on
paper, but what about hitting a floating log? A well-known designer
related a story both amusing and worrisome. A local builder of large
(90-foot, 27-meter) high-speed sportfishermen proudly showed him an
all-Kevlar, foam-sandwich hull panel that he'd used in a couple of
recent craft. The builder explained that his computer confirmed the
very, very thin skins (on the inside and outside of the foam) were more
than up to the job.
'To demonstrate his point, the builder took a hammer and wacked at the
sample panel mightily. With the hammer bouncing off harmlessly, he
offered it confidently to the skeptical architect. Taking the hammer,
the architect turned it claw-side down and -— with virtually no force at
all -— drove it right through Kevlar, the foam, and out the other side.
The builder's face turned white. He had a couple of boats out on the
water with this layup. The moral -— there's always a moral -— is that
the structural design of high-tech hulls is a complicated business.
Before you dash off to build or have built one of these miracle hulls,
make sure a good naval architect does a detailed structural analysis.'
That's what I was talking about when I mentioned penetration strength.
Sure a Gypsy isn't going to hit logs at 30 knots, but the scantlings
will already be redeuced in proportion to the speed. You can't let the
skins get too thin. 'Too thin' on foam is thinnner than 'too thin' on
ply. Avoiding that was where the extra weight came from.
Chris
Gary,
If you go to:
http://boatdesign.net/forums/archive/index.php/t-6334
.. you will find useful guidance on foam/glass scantlings. Following
the advice there, you should be able to decide what your scantlings
would need to be and then compare the calculated weight per unit area
with that of a ply skin -- and compare the cost too!
Howard
--- Inbolger@yahoogroups.com, "gbship" <gbship@c...> wrote:> Chris:
How do you figure scantlings for foam/glass construction? I've
If you go to:
http://boatdesign.net/forums/archive/index.php/t-6334
.. you will find useful guidance on foam/glass scantlings. Following
the advice there, you should be able to decide what your scantlings
would need to be and then compare the calculated weight per unit area
with that of a ply skin -- and compare the cost too!
Howard
--- Inbolger@yahoogroups.com, "gbship" <gbship@c...> wrote:> Chris:
How do you figure scantlings for foam/glass construction? I've
> done some online looking, but haven't found any resources.
Gary, "competition" changes things. IIRC Tom F Jones in "Low
Resistance Boats" wrote of a <100 lbs garvey he once designed for a
week-or-so long beachcruising race in which boats (solo) had to
carry all their necessaries, and be able to be beached well above
high water by their crew without any assistance of any kind each
night. I liked the idea of that little cute sneakbox style 3/4
decked cruiser a lot, and swear I would have built one if Jones
published plans. Its owner loved it and enjoyed lengthy cruises and
messing about in it for many years. It was no racer though. A wiser
Jones wrote that if he had to do it again for that type of
competition he would design something minimumalist canoe like. The
sailing was not quite as important a factor as lightness and rowing.
How about an adjusted "Zephyr" for two? length/beam > 6/1. (with
reduced scantlings? Anhinga at 23'5" has only 0.25" ply sides)
graeme
Resistance Boats" wrote of a <100 lbs garvey he once designed for a
week-or-so long beachcruising race in which boats (solo) had to
carry all their necessaries, and be able to be beached well above
high water by their crew without any assistance of any kind each
night. I liked the idea of that little cute sneakbox style 3/4
decked cruiser a lot, and swear I would have built one if Jones
published plans. Its owner loved it and enjoyed lengthy cruises and
messing about in it for many years. It was no racer though. A wiser
Jones wrote that if he had to do it again for that type of
competition he would design something minimumalist canoe like. The
sailing was not quite as important a factor as lightness and rowing.
How about an adjusted "Zephyr" for two? length/beam > 6/1. (with
reduced scantlings? Anhinga at 23'5" has only 0.25" ply sides)
graeme
--- Inbolger@yahoogroups.com, "gbship" <gbship@c...> wrote:
> Graeme, I'm not sure Jimmi would row as well as the others,
although it
> would be a possibility. It would be a better bet if two of us do
this
> competition instead of me doing it solo. I would tend to think a
multi-
> chine like Gypsy or Woodbo would be better, or if it's a sharpie
hull,
> it would have to be faily narrow for its length, like the Beach
Cruiser.
>
> Chris: How do you figure scantlings for foam/glass construction?
I've
> done some online looking, but haven't found any resources. A
friend
> laminated a couple layers of glass on either side of 3/8 inch foam
(I
> think that was the thickness) and you could whack it with a hammer
> without damage and it was considerably lighter than a ply sandwich
> would have been. I made some hatches for our Frolic2 of glass over
1/4-
> inch foam and those are reasonably strong, and very light, but not
> strong enough for use for a hull. I have no idea if I should use
> thicker foam, more glass, or both for suitable strength. For that
> matter, if the budget allows, it's possible I'll got to carbon
> fiber/foam, which should be even lighter, but again, I have no
idea of
> the suitable scantlings....
>
> Gary
Graeme, I'm not sure Jimmi would row as well as the others, although it
would be a possibility. It would be a better bet if two of us do this
competition instead of me doing it solo. I would tend to think a multi-
chine like Gypsy or Woodbo would be better, or if it's a sharpie hull,
it would have to be faily narrow for its length, like the Beach Cruiser.
Chris: How do you figure scantlings for foam/glass construction? I've
done some online looking, but haven't found any resources. A friend
laminated a couple layers of glass on either side of 3/8 inch foam (I
think that was the thickness) and you could whack it with a hammer
without damage and it was considerably lighter than a ply sandwich
would have been. I made some hatches for our Frolic2 of glass over 1/4-
inch foam and those are reasonably strong, and very light, but not
strong enough for use for a hull. I have no idea if I should use
thicker foam, more glass, or both for suitable strength. For that
matter, if the budget allows, it's possible I'll got to carbon
fiber/foam, which should be even lighter, but again, I have no idea of
the suitable scantlings....
Gary
would be a possibility. It would be a better bet if two of us do this
competition instead of me doing it solo. I would tend to think a multi-
chine like Gypsy or Woodbo would be better, or if it's a sharpie hull,
it would have to be faily narrow for its length, like the Beach Cruiser.
Chris: How do you figure scantlings for foam/glass construction? I've
done some online looking, but haven't found any resources. A friend
laminated a couple layers of glass on either side of 3/8 inch foam (I
think that was the thickness) and you could whack it with a hammer
without damage and it was considerably lighter than a ply sandwich
would have been. I made some hatches for our Frolic2 of glass over 1/4-
inch foam and those are reasonably strong, and very light, but not
strong enough for use for a hull. I have no idea if I should use
thicker foam, more glass, or both for suitable strength. For that
matter, if the budget allows, it's possible I'll got to carbon
fiber/foam, which should be even lighter, but again, I have no idea of
the suitable scantlings....
Gary
gbship wrote:
I forget the details, but a few years ago I sat down and worked out the
weight for Gypsy built out of various types of Ply and alternatively
from glassed foam. The foam was heavier than at least the lightest
(possibly all) ply variation.
I vaguely recall the issue was getting reasonable penetration protection.
Chris
> Graeme:Gary,
>
> Thanks. Found them. That beach cruiser is interesting. I'm looking
> for womething that can be built of foam/epoxy/glass instead of
> ply/glass for an ultra-light boat, hopefully in the 70-80 pound
> range. Candidates are these two boats, Michalak's Woodbo, and maybe
> Gypsy, with some modifications (I want a reefing sail and room to
> sleep on board under a boom tent. Not sure the Beach Cruiser could be
> done light enough, but it sure is a seductive design.
>
> Gary
I forget the details, but a few years ago I sat down and worked out the
weight for Gypsy built out of various types of Ply and alternatively
from glassed foam. The foam was heavier than at least the lightest
(possibly all) ply variation.
I vaguely recall the issue was getting reasonable penetration protection.
Chris
Actually, is the "Jinny" hull a slightly bigger "June Bug", or a re-
worked "Cold Water Sailboard" (Chapter 5 FS)?
I've thought about camper mods to "CWS".
cheers
graeme
--- Inbolger@yahoogroups.com, "graeme19121984" <graeme19121984@y...>
wrote:
worked "Cold Water Sailboard" (Chapter 5 FS)?
I've thought about camper mods to "CWS".
cheers
graeme
--- Inbolger@yahoogroups.com, "graeme19121984" <graeme19121984@y...>
wrote:
> Hi Gary, I just realised from here: (see pp 3 & 9)
>
>http://www.boatdesign.com/postings/Files/instbb/ib9.pdf
>
> that "Jinni" is a plumb-sided squareboat. Slightly bigger than "June
> Bug" eh? Pretty. Fast.
Hi Gary, I just realised from here: (see pp 3 & 9)
http://www.boatdesign.com/postings/Files/instbb/ib9.pdf
that "Jinni" is a plumb-sided squareboat. Slightly bigger than "June
Bug" eh? Pretty. Fast. Camp space for two, a tent that could also
cover both fore and aft storage compartents without the rainwater
runs from a mast stepped in the forward well.
Apparently Bolger mods include solent lug (easier reefing), lee
boards, and
Jim Michalak's mods of pivoting lee board/rudder, and balanced lug
(easier reefing but rainwater dowm mast).
Pre-glassed foam panels, cut and glued? Easy and quick build; but
may exceed your 80lbs limit? Wooboo also takes six sheets of ply, I
think.
graeme
http://www.boatdesign.com/postings/Files/instbb/ib9.pdf
that "Jinni" is a plumb-sided squareboat. Slightly bigger than "June
Bug" eh? Pretty. Fast. Camp space for two, a tent that could also
cover both fore and aft storage compartents without the rainwater
runs from a mast stepped in the forward well.
Apparently Bolger mods include solent lug (easier reefing), lee
boards, and
Jim Michalak's mods of pivoting lee board/rudder, and balanced lug
(easier reefing but rainwater dowm mast).
Pre-glassed foam panels, cut and glued? Easy and quick build; but
may exceed your 80lbs limit? Wooboo also takes six sheets of ply, I
think.
graeme
--- Inbolger@yahoogroups.com, "gbship" <gbship@c...> wrote:
> Graeme:
>
> Thanks. Found them. That beach cruiser is interesting. I'm looking
> for womething that can be built of foam/epoxy/glass instead of
> ply/glass for an ultra-light boat, hopefully in the 70-80 pound
> range. Candidates are these two boats, Michalak's Woodbo, and
maybe
> Gypsy, with some modifications (I want a reefing sail and room to
> sleep on board under a boom tent. Not sure the Beach Cruiser could
be
> done light enough, but it sure is a seductive design.
>
> Gary
>
> --- Inbolger@yahoogroups.com, "graeme19121984"
<graeme19121984@y...>
> wrote:
> > Gary,
> > if you look in this group's files under Perfect Skiff, or here:
> >
> >http://groups.yahoo.com/group/bolger/files/Perfect%20Skiff/
> >
> > The boats here, 'CSD Skiff', and 'Beach Cruiser Concept', are
> great!
> > PCB writes 'BCC' can sail through very rough water, including
surf.
> > What's rougher than surf :)?
> >
> > I'm inclined to prefer the 'BCC'. Is it a kind of
> > stretched'n'decked 'Jinni'? (not many images around of 'Jinni',
> > especially plan view, though the design is refered to plenty.
Its
> in
> > an old book I've been unable to get yet.)
> >
> > Do you know if PCB proved the concept of 'BCC'? Has done a
design
> > (perhaps for the allegedly infamous Woodenboat magazine early
> > 90's "Perfect Skiff Competition")? Or are the compromises (to
power
> > etc)in 'CSD Skiff' it?
> >
> > cheers
> > graeme
> >
> > --- Inbolger@yahoogroups.com, "gbship" <gbship@c...> wrote:
> > > Does anyone know of a link to pictures/plans for the
Commonsense
> > Skiff,
> > > a rowing/sailing/power combo that Bolger drew several years
ago?
> > >
> > > Thanks
> > >
> > > Gary Blankenship
Graeme:
Thanks. Found them. That beach cruiser is interesting. I'm looking
for womething that can be built of foam/epoxy/glass instead of
ply/glass for an ultra-light boat, hopefully in the 70-80 pound
range. Candidates are these two boats, Michalak's Woodbo, and maybe
Gypsy, with some modifications (I want a reefing sail and room to
sleep on board under a boom tent. Not sure the Beach Cruiser could be
done light enough, but it sure is a seductive design.
Gary
--- Inbolger@yahoogroups.com, "graeme19121984" <graeme19121984@y...>
wrote:
Thanks. Found them. That beach cruiser is interesting. I'm looking
for womething that can be built of foam/epoxy/glass instead of
ply/glass for an ultra-light boat, hopefully in the 70-80 pound
range. Candidates are these two boats, Michalak's Woodbo, and maybe
Gypsy, with some modifications (I want a reefing sail and room to
sleep on board under a boom tent. Not sure the Beach Cruiser could be
done light enough, but it sure is a seductive design.
Gary
--- Inbolger@yahoogroups.com, "graeme19121984" <graeme19121984@y...>
wrote:
> Gary,great!
> if you look in this group's files under Perfect Skiff, or here:
>
>http://groups.yahoo.com/group/bolger/files/Perfect%20Skiff/
>
> The boats here, 'CSD Skiff', and 'Beach Cruiser Concept', are
> PCB writes 'BCC' can sail through very rough water, including surf.in
> What's rougher than surf :)?
>
> I'm inclined to prefer the 'BCC'. Is it a kind of
> stretched'n'decked 'Jinni'? (not many images around of 'Jinni',
> especially plan view, though the design is refered to plenty. Its
> an old book I've been unable to get yet.)
>
> Do you know if PCB proved the concept of 'BCC'? Has done a design
> (perhaps for the allegedly infamous Woodenboat magazine early
> 90's "Perfect Skiff Competition")? Or are the compromises (to power
> etc)in 'CSD Skiff' it?
>
> cheers
> graeme
>
> --- Inbolger@yahoogroups.com, "gbship" <gbship@c...> wrote:
> > Does anyone know of a link to pictures/plans for the Commonsense
> Skiff,
> > a rowing/sailing/power combo that Bolger drew several years ago?
> >
> > Thanks
> >
> > Gary Blankenship
Gary,
if you look in this group's files under Perfect Skiff, or here:
http://groups.yahoo.com/group/bolger/files/Perfect%20Skiff/
The boats here, 'CSD Skiff', and 'Beach Cruiser Concept', are great!
PCB writes 'BCC' can sail through very rough water, including surf.
What's rougher than surf :)?
I'm inclined to prefer the 'BCC'. Is it a kind of
stretched'n'decked 'Jinni'? (not many images around of 'Jinni',
especially plan view, though the design is refered to plenty. Its in
an old book I've been unable to get yet.)
Do you know if PCB proved the concept of 'BCC'? Has done a design
(perhaps for the allegedly infamous Woodenboat magazine early
90's "Perfect Skiff Competition")? Or are the compromises (to power
etc)in 'CSD Skiff' it?
cheers
graeme
if you look in this group's files under Perfect Skiff, or here:
http://groups.yahoo.com/group/bolger/files/Perfect%20Skiff/
The boats here, 'CSD Skiff', and 'Beach Cruiser Concept', are great!
PCB writes 'BCC' can sail through very rough water, including surf.
What's rougher than surf :)?
I'm inclined to prefer the 'BCC'. Is it a kind of
stretched'n'decked 'Jinni'? (not many images around of 'Jinni',
especially plan view, though the design is refered to plenty. Its in
an old book I've been unable to get yet.)
Do you know if PCB proved the concept of 'BCC'? Has done a design
(perhaps for the allegedly infamous Woodenboat magazine early
90's "Perfect Skiff Competition")? Or are the compromises (to power
etc)in 'CSD Skiff' it?
cheers
graeme
--- Inbolger@yahoogroups.com, "gbship" <gbship@c...> wrote:
> Does anyone know of a link to pictures/plans for the Commonsense
Skiff,
> a rowing/sailing/power combo that Bolger drew several years ago?
>
> Thanks
>
> Gary Blankenship
Does anyone know of a link to pictures/plans for the Commonsense Skiff,
a rowing/sailing/power combo that Bolger drew several years ago?
Thanks
Gary Blankenship
a rowing/sailing/power combo that Bolger drew several years ago?
Thanks
Gary Blankenship