Re: [bolger] Flat / curved ?
One good reason would be a softer ride, no pounding, however if you are
building a slow moving flat bottomed boat you wont need to be concerned too
much about it....
Grant
on 6/2/04 5:49 PM, alternateuser2001 atalternateuser2001@...wrote:
building a slow moving flat bottomed boat you wont need to be concerned too
much about it....
Grant
on 6/2/04 5:49 PM, alternateuser2001 atalternateuser2001@...wrote:
>
> Hi there ,
>
> 'Got a question for you all - can anyone explain to me why
> the 'classic' boats all have a 'curved' underside (aiii...what a
> terrible terminology to USE , dutchman ...and that to a boatbuilding
> group ... Go wash your mouth with some soap !! ) While the boats from
> Mr.Bolger (and other modern boats) often have a much more "flatt"
> one ??
> I DO know that it would be much better to take up some sort a course
> in 'elementary shipbuilding' or something like that, and I will in
> due time...but I just was curious .
> Allready I know (by studying the texts and articles from this great
> site (!) that my own little "shanty-boat' / 'narrow-boat' is gonna
> get a flatbottom - she will be going very slowly through very calm
> water, with allmost no deep water at all ... So that will do just
> fine then .
>
> If anyone would be so kind as to explain this a little I would be
> very gratefull for that.
> Also my earlier offer; to be willing to search for anything "Dutch-
> related" still stands, ok ?!
>
> Sincere greetings,
>
> M.Hulleman
>
>
>
>
> 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
>
>
>
>
>
One other issue with flat surfaces -- they "oil can." By introducing a
curve (aka arch) the stresses do not reverse and the material/structure
lasts longer.
Roger
derbyrm@...
derbyrm.mystarband.net/default.htm
curve (aka arch) the stresses do not reverse and the material/structure
lasts longer.
Roger
derbyrm@...
derbyrm.mystarband.net/default.htm
----- Original Message -----
From: "pvanderwaart" <pvanderwaart@...>
>
> There are many complicating factors, and many different ideas. Boat
> shape questions do not have single answers.
>
> The weight of the boat is an important factor. The lighter a boat is,
> the flatter the bottom will be. A light boat can't push a rounded
> shape deep enough into the water. Tenessee is very light for her
> size. Bolger uses a very flat bottom so the boat does not go deep in
> the water. It only has to push a little surface water aside as it
> moves along. (And it is an easy shape to build.)
>
> A shanty boat built on a barge-like shape will have a flat bottom
> because it is easy to build and will float in shallow water. It will
> never go anywere fast, so the shape does not have to be very
> boatlike. The flat bottom will also rock the least.
>
> Peter
>But that leaves me with the question: for a sort-of "narrow-like-If a boat is going to go very slow, then the "barge shape: or "scow shape"
>shanty-boat", the flatt hull ( 'box-style' they call it
>at 'cimplicityboats') like f.o. off Bolger's Tennessee , isn't a good
>idea ,because this boat isn't going to plane over the water...??
is no problem. When scow shapes are very large they are very efficient load
carriers. Keep the transom out of the water. In the case of the scow keep
both transoms out of the water.
There is another reason for flat bottom boats. In the USA, many small
working boats were "crossplanked" that is the boards on the bottom were
nailed across. This makes for an easily built, cheap and very strong hull.
Sometimes there is a little "V" to the bottom but the principle remains the
same.
Cheap and strong is what the fishermen wanted.
--
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.
_________________________________
>If anyone would be so kind as to explain this a little I would beBut there are also Dutch boats with flat bottoms!
>very gratefull for that.
>Also my earlier offer; to be willing to search for anything "Dutch-
>related" still stands, ok ?!
>
>Sincere greetings,
>
>M.Hulleman
--
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.
_________________________________
Thanks people ...
that 's a LOT of info, a lot to think about as well.
I'm off to make some planns and sketches !
Thanks again .
Sincere greetings,
M.Hulleman
that 's a LOT of info, a lot to think about as well.
I'm off to make some planns and sketches !
Thanks again .
Sincere greetings,
M.Hulleman
There are many complicating factors, and many different ideas. Boat
shape questions do not have single answers.
The weight of the boat is an important factor. The lighter a boat is,
the flatter the bottom will be. A light boat can't push a rounded
shape deep enough into the water. Tenessee is very light for her
size. Bolger uses a very flat bottom so the boat does not go deep in
the water. It only has to push a little surface water aside as it
moves along. (And it is an easy shape to build.)
A shanty boat built on a barge-like shape will have a flat bottom
because it is easy to build and will float in shallow water. It will
never go anywere fast, so the shape does not have to be very
boatlike. The flat bottom will also rock the least.
Peter
--- Inbolger@yahoogroups.com, "alternateuser2001"
<alternateuser2001@y...> wrote:
shape questions do not have single answers.
The weight of the boat is an important factor. The lighter a boat is,
the flatter the bottom will be. A light boat can't push a rounded
shape deep enough into the water. Tenessee is very light for her
size. Bolger uses a very flat bottom so the boat does not go deep in
the water. It only has to push a little surface water aside as it
moves along. (And it is an easy shape to build.)
A shanty boat built on a barge-like shape will have a flat bottom
because it is easy to build and will float in shallow water. It will
never go anywere fast, so the shape does not have to be very
boatlike. The flat bottom will also rock the least.
Peter
--- Inbolger@yahoogroups.com, "alternateuser2001"
<alternateuser2001@y...> wrote:
>is -
> Thank you very much !! Wow ! that cleared up a LOT , for me that
> the whole "hull-form" issue 's much more clear now . And howlogical
> it is, when you think of it; what would move the easiest throughgood
> water - a square block or a needle ?! (why didn't I think of
> that ...;)Thanks!
>
> But that leaves me with the question: for a sort-of "narrow-like-
> shanty-boat", the flatt hull ( 'box-style' they call it
> at 'cimplicityboats') like f.o. off Bolger's Tennessee , isn't a
> idea ,because this boat isn't going to plane over the water...??
Thank you very much !! Wow ! that cleared up a LOT , for me that is -
the whole "hull-form" issue 's much more clear now . And how logical
it is, when you think of it; what would move the easiest through
water - a square block or a needle ?! (why didn't I think of
that ...;)Thanks!
But that leaves me with the question: for a sort-of "narrow-like-
shanty-boat", the flatt hull ( 'box-style' they call it
at 'cimplicityboats') like f.o. off Bolger's Tennessee , isn't a good
idea ,because this boat isn't going to plane over the water...??
the whole "hull-form" issue 's much more clear now . And how logical
it is, when you think of it; what would move the easiest through
water - a square block or a needle ?! (why didn't I think of
that ...;)Thanks!
But that leaves me with the question: for a sort-of "narrow-like-
shanty-boat", the flatt hull ( 'box-style' they call it
at 'cimplicityboats') like f.o. off Bolger's Tennessee , isn't a good
idea ,because this boat isn't going to plane over the water...??
The greatest volume you can enclose for a particular surface area will
be in the shape of a circle. Thus, round bottom boats minimize the
amount of skin friction. Additionally, they minimize turbulance if
designed correctly.
Flat bottomed hulls have higher initial stability. They don't roll as
much. Most important, they are easier to build. And least important,
from Bolger's point of view, they tend to be ugly.
Doug
--- Inbolger@yahoogroups.com, "alternateuser2001"
<alternateuser2001@y...> wrote:
be in the shape of a circle. Thus, round bottom boats minimize the
amount of skin friction. Additionally, they minimize turbulance if
designed correctly.
Flat bottomed hulls have higher initial stability. They don't roll as
much. Most important, they are easier to build. And least important,
from Bolger's point of view, they tend to be ugly.
Doug
--- Inbolger@yahoogroups.com, "alternateuser2001"
<alternateuser2001@y...> wrote:
>boats from
> Hi there ,
>
> 'Got a question for you all - can anyone explain to me why
> the 'classic' boats all have a 'curved' underside ... While the
> Mr.Bolger (and other modern boats) often have a much more "flatt"
> one ??
Most of the Bolger 'square boats' IE, those in the
Advanced Sharpie series, and others, actually are not
flat bottomed, but rather they are very much curved.
[The exception are a few of his boats that are
intended to be planing boats, like Wyoming,
or Sneakeasy.]
These 'Square Boats' look 'flat' because they are made from
bent sheets of plywood. They bend in only two dimensions
rather than three.
Bolger's concept for these 'square' boats is that if
he designs the curve of the sides to match the
curve of the bottom, then there is no differential
pressure as the water flows around the boat. The
particles of water have equal distance to travel
without regard as they flow across the bottom
or the side.
If the curve of the bottom did not match the sides
then the differential pressure of the flowing water
would 'suck' water across the chine edges between
the bottom and the sides. This turbulence would
be detrimental to the performence of the boats.
Boats that have curves in three directions rather
than two directions also are intended to reduce this
turbulence from differential pressure of the flowing
water, but they achieve this by having gradual changes
in the directions and distances of the flow of water.
On Wed, 02 Jun 2004 21:49:43 -0000, alternateuser2001
<alternateuser2001@...> wrote:
Advanced Sharpie series, and others, actually are not
flat bottomed, but rather they are very much curved.
[The exception are a few of his boats that are
intended to be planing boats, like Wyoming,
or Sneakeasy.]
These 'Square Boats' look 'flat' because they are made from
bent sheets of plywood. They bend in only two dimensions
rather than three.
Bolger's concept for these 'square' boats is that if
he designs the curve of the sides to match the
curve of the bottom, then there is no differential
pressure as the water flows around the boat. The
particles of water have equal distance to travel
without regard as they flow across the bottom
or the side.
If the curve of the bottom did not match the sides
then the differential pressure of the flowing water
would 'suck' water across the chine edges between
the bottom and the sides. This turbulence would
be detrimental to the performence of the boats.
Boats that have curves in three directions rather
than two directions also are intended to reduce this
turbulence from differential pressure of the flowing
water, but they achieve this by having gradual changes
in the directions and distances of the flow of water.
On Wed, 02 Jun 2004 21:49:43 -0000, alternateuser2001
<alternateuser2001@...> wrote:
>
>
> Hi there ,
>
> 'Got a question for you all - can anyone explain to me why
> the 'classic' boats all have a 'curved' underside (aiii...what a
> terrible terminology to USE , dutchman ...and that to a boatbuilding
> group ... Go wash your mouth with some soap !! ) While the boats from
> Mr.Bolger (and other modern boats) often have a much more "flatt"
> one ??
> I DO know that it would be much better to take up some sort a course
> in 'elementary shipbuilding' or something like that, and I will in
> due time...but I just was curious .
> Allready I know (by studying the texts and articles from this great
> site (!) that my own little "shanty-boat' / 'narrow-boat' is gonna
> get a flatbottom - she will be going very slowly through very calm
> water, with allmost no deep water at all ... So that will do just
> fine then .
>
> If anyone would be so kind as to explain this a little I would be
> very gratefull for that.
> Also my earlier offer; to be willing to search for anything "Dutch-
> related" still stands, ok ?!
>
> Sincere greetings,
>
> M.Hulleman
>
>
> 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
>
>
>
>
>
Hi there ,
'Got a question for you all - can anyone explain to me why
the 'classic' boats all have a 'curved' underside (aiii...what a
terrible terminology to USE , dutchman ...and that to a boatbuilding
group ... Go wash your mouth with some soap !! ) While the boats from
Mr.Bolger (and other modern boats) often have a much more "flatt"
one ??
I DO know that it would be much better to take up some sort a course
in 'elementary shipbuilding' or something like that, and I will in
due time...but I just was curious .
Allready I know (by studying the texts and articles from this great
site (!) that my own little "shanty-boat' / 'narrow-boat' is gonna
get a flatbottom - she will be going very slowly through very calm
water, with allmost no deep water at all ... So that will do just
fine then .
If anyone would be so kind as to explain this a little I would be
very gratefull for that.
Also my earlier offer; to be willing to search for anything "Dutch-
related" still stands, ok ?!
Sincere greetings,
M.Hulleman
'Got a question for you all - can anyone explain to me why
the 'classic' boats all have a 'curved' underside (aiii...what a
terrible terminology to USE , dutchman ...and that to a boatbuilding
group ... Go wash your mouth with some soap !! ) While the boats from
Mr.Bolger (and other modern boats) often have a much more "flatt"
one ??
I DO know that it would be much better to take up some sort a course
in 'elementary shipbuilding' or something like that, and I will in
due time...but I just was curious .
Allready I know (by studying the texts and articles from this great
site (!) that my own little "shanty-boat' / 'narrow-boat' is gonna
get a flatbottom - she will be going very slowly through very calm
water, with allmost no deep water at all ... So that will do just
fine then .
If anyone would be so kind as to explain this a little I would be
very gratefull for that.
Also my earlier offer; to be willing to search for anything "Dutch-
related" still stands, ok ?!
Sincere greetings,
M.Hulleman