Re: Chines (was: Bolger on sharpies)
Ruzer is on the money. The Lions Paw (30 Odd Boats) and Sir Joseph Banks (BWAOM last chapter) both had this feature for protection and easy of welding. NOT for 'lateral plane'. Both boats use lee boards. I've forgotten where I saw them but one designer of big passage makers uses chine runners on motor sailer and straight power designs.
Oddly, there are 2 Lions Paw projects out there, both finished to about the same stage, both just sitting incomplete.
Don
Oddly, there are 2 Lions Paw projects out there, both finished to about the same stage, both just sitting incomplete.
Don
--- Inbolger@yahoogroups.com, "c.ruzer" <c.ruzer@...> wrote:
>
> 30 ODD p 92. Rather, it was to facilitate downwards welding as well as protecting the thinner side plating when grounded.
>
>.....He deliberately specified that the bottom plating stick out past the chine both as protection and as a kind of lateral plane. Can't remember which book it's in, maybe somebody else here does. I believe Matt Layden's boat all have something like this--no keel to speak of...
30 ODD p 92. Rather, it was to facilitate downwards welding as well as protecting the thinner side plating when grounded.
It's been said that Matt Layden said to someone that PCB's comment there that such an excrescence doesn't make much added drag in such a proportioned hull, but particularly the further comment that it inhibits cross-chine eddying flow upped ML's reasons to experiment with chine runners on sharpies.
It's been said that Matt Layden said to someone that PCB's comment there that such an excrescence doesn't make much added drag in such a proportioned hull, but particularly the further comment that it inhibits cross-chine eddying flow upped ML's reasons to experiment with chine runners on sharpies.
--- Inbolger@yahoogroups.com, "etap28" <dave.irland@...> wrote:
>
>
> Kent,
> In one of Bolger's books there's a huge sharpie he designed for steel, Lion's Paw I'm pretty sure was the boat (giant Black Skimmer). He deliberately specified that the bottom plating stick out past the chine both as protection and as a kind of lateral plane. Can't remember which book it's in, maybe somebody else here does. I believe Matt Layden's boat all have something like this--no keel to speak of
> Dave
>
>
> --- Inbolger@yahoogroups.com, Kent <kent@> wrote:
> >
> > Hi folks --
> >
> > While we're on the subject of chines & shallow draft, does anyone
> > here have experience with "chine runners" or other ultra-shallow
> > keels? I've read reports of them here and there, but also some
> > negative comments. I didn't realize Black Skimmer had an external
> > chine log; I guess that's kind of the same thing?
> >
> > I'm working on a design of my own, and I'd love to try something like
> > this as a way to eliminate the need for a keel, leeboards, etc. ...
> > but only if I'm confident that it will work. I've read some material
> > on-line about Matt Layden's boats such as "Paradox." Is there
> > anything else out there, maybe about experience on larger boats?
--- Inbolger@yahoogroups.com, Kent <kent@...> wrote:
> ..."chine runners" ... Is there anything else out there, maybeChris Morejohn (sp?)
> about experience on larger boats?
Cool. I've seen pics of Matt Layden's little boats with winglets on them. I've been wondering how to make them.
John Boy
From:Harry James <welshman@...>
To:bolger@yahoogroups.com
Sent:Fri, January 7, 2011 6:39:01 PM
Subject:Re: [bolger] Chines
John Boy
."It's the tides, man. They can either work for you or they can work against you...Confidentially, I've had this problem with the tides before."--Captain RonFrom:Harry James <welshman@...>
To:bolger@yahoogroups.com
Sent:Fri, January 7, 2011 6:39:01 PM
Subject:Re: [bolger] Chines
See K Designs antivortex panels web page at
http://www.ikarus342000.com/Looseends.htm
Click on antivortex link.
HJ
On 1/6/2011 8:14 PM, Kent wrote:
> Hi folks --
>
> While we're on the subject of chines& shallow draft, does anyone
> here have experience with "chine runners" or other ultra-shallow
> keels? I've read reports of them here and there, but also some
> negative comments. I didn't realize Black Skimmer had an external
> chine log; I guess that's kind of the same thing?
>
> I'm working on a design of my own, and I'd love to try something like
> this as a way to eliminate the need for a keel, leeboards, etc. ...
> but only if I'm confident that it will work. I've read some material
> on-line about Matt Layden's boats such as "Paradox." Is there
> anything else out there, maybe about experience on larger boats?
>
> Thanks -- Kent
>
>
>
>> I used to anchor my Black Skimmer in a tidal pond where I had just
>> about total privacy. The downside for most boats was that at low
>> tide you would be floating in about a foot of water. As a result I
>> had a huge chunk of priceless real estate to myself. Spent many a
>> night out there in that miraculously uninhabited pristine place. I
>> very well remember one day setting sail at around low tide in there,
>> in a very strong breeze, probably about 15, as is typical on an
>> August afternoon on Martha's Vineyard, both leeboards fully in the
>> "up" position. That boat hung on and actually went to windward
>> reasonably well, I'm sure partly due to the square chine but also
>> I'm positive because of the external chine log. It's pretty hard for
>> water to flow horizontally past a 2x4 on edge. Occasionally I think
>> about just how radical it was for a boat designer to have an idea
>> like that and just go ahead and do it.
>
>
>
>
>
> ------------------------------------
>
> Bolger rules!!!
> - NO "GO AWAY SPAMMER!" posts!!! Please!
> - no cursing, flaming, trolling, spamming, respamming, 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.comYahoo! Groups Links
>
>
>
>
See K Designs antivortex panels web page at
http://www.ikarus342000.com/Looseends.htm
Click on antivortex link.
HJ
http://www.ikarus342000.com/Looseends.htm
Click on antivortex link.
HJ
On 1/6/2011 8:14 PM, Kent wrote:
> Hi folks --
>
> While we're on the subject of chines& shallow draft, does anyone
> here have experience with "chine runners" or other ultra-shallow
> keels? I've read reports of them here and there, but also some
> negative comments. I didn't realize Black Skimmer had an external
> chine log; I guess that's kind of the same thing?
>
> I'm working on a design of my own, and I'd love to try something like
> this as a way to eliminate the need for a keel, leeboards, etc. ...
> but only if I'm confident that it will work. I've read some material
> on-line about Matt Layden's boats such as "Paradox." Is there
> anything else out there, maybe about experience on larger boats?
>
> Thanks -- Kent
>
>
>
>> I used to anchor my Black Skimmer in a tidal pond where I had just
>> about total privacy. The downside for most boats was that at low
>> tide you would be floating in about a foot of water. As a result I
>> had a huge chunk of priceless real estate to myself. Spent many a
>> night out there in that miraculously uninhabited pristine place. I
>> very well remember one day setting sail at around low tide in there,
>> in a very strong breeze, probably about 15, as is typical on an
>> August afternoon on Martha's Vineyard, both leeboards fully in the
>> "up" position. That boat hung on and actually went to windward
>> reasonably well, I'm sure partly due to the square chine but also
>> I'm positive because of the external chine log. It's pretty hard for
>> water to flow horizontally past a 2x4 on edge. Occasionally I think
>> about just how radical it was for a boat designer to have an idea
>> like that and just go ahead and do it.
>
>
>
>
>
> ------------------------------------
>
> Bolger rules!!!
> - NO "GO AWAY SPAMMER!" posts!!! Please!
> - no cursing, flaming, trolling, spamming, respamming, 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.comYahoo! Groups Links
>
>
>
>
Kent,
In one of Bolger's books there's a huge sharpie he designed for steel, Lion's Paw I'm pretty sure was the boat (giant Black Skimmer). He deliberately specified that the bottom plating stick out past the chine both as protection and as a kind of lateral plane. Can't remember which book it's in, maybe somebody else here does. I believe Matt Layden's boat all have something like this--no keel to speak of
Dave
In one of Bolger's books there's a huge sharpie he designed for steel, Lion's Paw I'm pretty sure was the boat (giant Black Skimmer). He deliberately specified that the bottom plating stick out past the chine both as protection and as a kind of lateral plane. Can't remember which book it's in, maybe somebody else here does. I believe Matt Layden's boat all have something like this--no keel to speak of
Dave
--- Inbolger@yahoogroups.com, Kent <kent@...> wrote:
>
> Hi folks --
>
> While we're on the subject of chines & shallow draft, does anyone
> here have experience with "chine runners" or other ultra-shallow
> keels? I've read reports of them here and there, but also some
> negative comments. I didn't realize Black Skimmer had an external
> chine log; I guess that's kind of the same thing?
>
> I'm working on a design of my own, and I'd love to try something like
> this as a way to eliminate the need for a keel, leeboards, etc. ...
> but only if I'm confident that it will work. I've read some material
> on-line about Matt Layden's boats such as "Paradox." Is there
> anything else out there, maybe about experience on larger boats?
>
> Thanks -- Kent
>
>
>
> >I used to anchor my Black Skimmer in a tidal pond where I had just
> >about total privacy. The downside for most boats was that at low
> >tide you would be floating in about a foot of water. As a result I
> >had a huge chunk of priceless real estate to myself. Spent many a
> >night out there in that miraculously uninhabited pristine place. I
> >very well remember one day setting sail at around low tide in there,
> >in a very strong breeze, probably about 15, as is typical on an
> >August afternoon on Martha's Vineyard, both leeboards fully in the
> >"up" position. That boat hung on and actually went to windward
> >reasonably well, I'm sure partly due to the square chine but also
> >I'm positive because of the external chine log. It's pretty hard for
> >water to flow horizontally past a 2x4 on edge. Occasionally I think
> >about just how radical it was for a boat designer to have an idea
> >like that and just go ahead and do it.
>
Hi folks --
While we're on the subject of chines & shallow draft, does anyone
here have experience with "chine runners" or other ultra-shallow
keels? I've read reports of them here and there, but also some
negative comments. I didn't realize Black Skimmer had an external
chine log; I guess that's kind of the same thing?
I'm working on a design of my own, and I'd love to try something like
this as a way to eliminate the need for a keel, leeboards, etc. ...
but only if I'm confident that it will work. I've read some material
on-line about Matt Layden's boats such as "Paradox." Is there
anything else out there, maybe about experience on larger boats?
Thanks -- Kent
While we're on the subject of chines & shallow draft, does anyone
here have experience with "chine runners" or other ultra-shallow
keels? I've read reports of them here and there, but also some
negative comments. I didn't realize Black Skimmer had an external
chine log; I guess that's kind of the same thing?
I'm working on a design of my own, and I'd love to try something like
this as a way to eliminate the need for a keel, leeboards, etc. ...
but only if I'm confident that it will work. I've read some material
on-line about Matt Layden's boats such as "Paradox." Is there
anything else out there, maybe about experience on larger boats?
Thanks -- Kent
>I used to anchor my Black Skimmer in a tidal pond where I had just
>about total privacy. The downside for most boats was that at low
>tide you would be floating in about a foot of water. As a result I
>had a huge chunk of priceless real estate to myself. Spent many a
>night out there in that miraculously uninhabited pristine place. I
>very well remember one day setting sail at around low tide in there,
>in a very strong breeze, probably about 15, as is typical on an
>August afternoon on Martha's Vineyard, both leeboards fully in the
>"up" position. That boat hung on and actually went to windward
>reasonably well, I'm sure partly due to the square chine but also
>I'm positive because of the external chine log. It's pretty hard for
>water to flow horizontally past a 2x4 on edge. Occasionally I think
>about just how radical it was for a boat designer to have an idea
>like that and just go ahead and do it.
I used to anchor my Black Skimmer in a tidal pond where I had just about total privacy. The downside for most boats was that at low tide you would be floating in about a foot of water. As a result I had a huge chunk of priceless real estate to myself. Spent many a night out there in that miraculously uninhabited pristine place. I very well remember one day setting sail at around low tide in there, in a very strong breeze, probably about 15, as is typical on an August afternoon on Martha's Vineyard, both leeboards fully in the "up" position. That boat hung on and actually went to windward reasonably well, I'm sure partly due to the square chine but also I'm positive because of the external chine log. It's pretty hard for water to flow horizontally past a 2x4 on edge. Occasionally I think about just how radical it was for a boat designer to have an idea like that and just go ahead and do it.
--- Inbolger@yahoogroups.com, "Susanne@..." <philbolger@...> wrote:
>
> Amongst the hard-core critics of sharpies - none in this forum it seems - what is too often overlooked is what Bob Wise just touched upon. We've called it 'chine-sailing' - a different perspective on the eddy issue.
> Particularly in super-shallow waters, nothing will 'hang on' as well as a hard chine - unrounded. When no board can be down deeply enough to be particularly effective, the hard chine will work for you.
>
> This is a major conceptual issues which drove Phil's and our persistent focus on sharpies. Being able to armor that chine with slightly protruding - more eddies! - steel-plate ballast is a sweet side-effect.
>
> When you see fiberglass or metal boats, production or custom, in shallow water near the beach, but all round/multi-chine underwater, you know they just about had to get there by power. Advertised 'Shallow Draft' does not mean you can sail in shallow waters... Which closes off many waters and constitutes a safety-challenge, as there may well be times when 'chine-sailing' is the only thing between you and a leeshore.
>
> That is why typically Phil's Barge-Yachts have a long shallow keel below the free-flow hullshape to allow some 'traction. Still, while aesthetically beautiful and 'test-tank'-/CFD-correct in their no-chine flow-pattern, they may for coastal cruising utility still be less desirable since they can not be armored at the turn of the bilge to casually explore the shallows under sail or race across them in a gale towards a sheltered harbor.
>
> Between simplicity of construction, ability to massively armor the bottom and chine for routine shallow-water cruising and daily grounding out, plus the happy addition of foam-plate for insulation (multi-season habitability) and the option of building into a plywood-sharpie 'sinking-resistance' via enough foam and ply, there is not much that can compete conceptually and practically with a properly-proportioned sharpie cruiser, especially one with the vee-nose or modified cutwater-nose. We thought/think they are a rigor.
> ----- Original Message -----
> From: loosemoosefilmworks
> To:bolger@yahoogroups.com
> Sent: Wednesday, January 05, 2011 9:43 AM
> Subject: [bolger] Re: Bolger on sharpies
>
>
>
>
> We should not lose sight of reality in the face of theoretical conjecture...
>
> Our Loose Moose (a Jessie Cooper) and Loose Moose 2, I suppose, could have had a bit better performing hull shape and when we were talking with Phil at the beginning of the Loose Moose 2 project I suggested that if I were to cold mold the chine that we'd be a fair bit slippery through the water and faster is no bad thing. Phil wrote back and agreed that the result would deliver a faster hull but also, in the grand scheme of things, seriously hamper windward ability. Sort of a one step forward and two steps back situation.
>
> The thing is, Loose Moose and Loose Moose 2 sailed so well you never found yourself wishing you had a more efficient hull form because the one you had did just fine (thank you very much Mr Bolger) and while I am sure a more refined and engineered hull form would have been a bit faster, what would be the point?
>
> My all time favorite VW advertisement (and if anyone knows of a copy floating around I am looking for one)where the point was made that the VW bug had four wheels... Just like the Rolls Royce, did 55MPH in a 55MPH zone just like the Ferrari...and so on. The point as related to sharpies and boat design is that as long as they do the work they were intended to it hardly makes sense to bash them for not doing more or even wishing they could.
>
> Bob
>
>http://boatbits.blogspot.com/
>http://fishingundersail.blogspot.com/
>http://islandgourmand.blogspot.com/
>
> Bob:Well we liked the sailing ability of our JC enough that we had Phil stretch it out to 37 feet for the Loose Moose 2 design... That says something.
> What is your opinion of Jessie Cooper's sailing ability, particularly under what conditions would the bottom pound/slap?
Seriously the only problem we felt it had was it was simply a little short for a lot of the seas we were experienced in the English Channel and North Sea and that a longer hull was the answer. (it was)
The pounding and slapping issue in our opinion is the most talked about but non-problematic issue with sharpies. Having spent the last few years on a non-sharpie production boat (a CAL 34) sharpie slapping/pounding thing is really a non issue. Our CAL going to windward slams and pounds as much or more than our Bolger sharpies and as fiberglass is a noisier medium than plywood the slap noise in an anchorage is louder in a fiberglass boat than a plywood one. Though funny how no one complains about it with fiberglass boats.
The answer to pounding and slap is more a thing of seamanship (a thing of bygone eras it would seem) as the most simple fix is to change the course a kiss and re-find the sweet spot. On sailboats the proper course to get somewhere is seldom a straight line but here in the Caribbean I see people choosing the worst possible course more often than not when falling off a couple of degrees would make for a much more comfortable ride with no slapping or pounding...
Bob
http://boatbits.blogspot.com/
http://fishingundersail.blogspot.com/
http://islandgourmand.blogspot.com/
> We've called it 'chine-sailing' - a different perspective on the eddy issue.I wonder does the sharpie lee chine simply 'dig in', "hang on", or does it enhance a lifting body effect of the immersed section bilatteral asymetry when heeled that's acting to windward? [For example enhancement perhaps could be due to the hard chine initiating down stream (to windward, across the bottom) very low pressure vortices, or it perhaps may be by fencing off a high pressure flow area from a low pressure area (immersed lee side from bottom).] Would not slight chine protrusions, fences, actually increase the effect?
Thoughts of bilateral asymetry bring once more to mind that well travelled old sailor Richard Carsen's article on the windward benefits of a lob-sided 'vesica' (water plane outline):
"Now, if you take any boat and look at the main waterline (plan view) at rest, even boats with transoms, you will find that that waterline has the shape of a vesica, the aft point is where the transom touches the water. This vesica however will be somewhat mis-formed; instead of the pure arc, part of a circle, it will have bulges in places, in the buttocks, or hollows, near the stem. However, the two sides are still equal, though they are mirror images of each other.
Now, when I tilt the boat towards port or starboard, the lines, and the area they enclose, become unequal. I have found that something can be deduced from the shape, the now distorted shape, of these two areas.
It was the scow which first put me wise to that. The scow crabs (to windward), that is, she has a sideward component to her movement. The scow is vesica shaped with the ends cut off. But when you tilt her, you again form a vesica, with one of the chines as the longitudinal axis, but greatly un-equal areas at each side. Look at the draw-ing. Now, by the law that governs the action of foils (air or hydro), there now exists a force, when the craft moves thru the water, that will pull it in the direction of the largest area and the greatest bend; more about the latter later.
...'I' shows what happened to a sharpie when heeled. The ends were supposed to be raised above the water. The waterline then shows the pattern of the scow. It is my thought that this vessel sports a sharp bow instead of the flat transom, but was otherwise conceived as a scow in the way the Chesapeake watermen named their craft, a sharpie scow!" - Dreamboats, MAIB, September 15, 1998 Issue - diagrams and article available here:
http://web.archive.org/web/20080803231710/www.messingaboutinboats.com/archives/mbissueseptember15-98.html
Bob:
What is your opinion of Jessie Cooper's sailing ability, particularly under what conditions would the bottom pound/slap?
Re: the hard chine -- my Zephyr would make progress to windward without the leeboard in extemely shallow water. You could about feel the chine digging in and helping. Of course there was noticeable leeway, but the progress was decent.
Gary
What is your opinion of Jessie Cooper's sailing ability, particularly under what conditions would the bottom pound/slap?
Re: the hard chine -- my Zephyr would make progress to windward without the leeboard in extemely shallow water. You could about feel the chine digging in and helping. Of course there was noticeable leeway, but the progress was decent.
Gary
--- Inbolger@yahoogroups.com, "loosemoosefilmworks" <loosemoosefilmworks@...> wrote:
>
>
> We should not lose sight of reality in the face of theoretical conjecture...
>
> Our Loose Moose (a Jessie Cooper) and Loose Moose 2, I suppose, could have had a bit better performing hull shape and when we were talking with Phil at the beginning of the Loose Moose 2 project I suggested that if I were to cold mold the chine that we'd be a fair bit slippery through the water and faster is no bad thing. Phil wrote back and agreed that the result would deliver a faster hull but also, in the grand scheme of things, seriously hamper windward ability. Sort of a one step forward and two steps back situation.
>
> The thing is, Loose Moose and Loose Moose 2 sailed so well you never found yourself wishing you had a more efficient hull form because the one you had did just fine (thank you very much Mr Bolger) and while I am sure a more refined and engineered hull form would have been a bit faster, what would be the point?
>
> My all time favorite VW advertisement (and if anyone knows of a copy floating around I am looking for one)where the point was made that the VW bug had four wheels... Just like the Rolls Royce, did 55MPH in a 55MPH zone just like the Ferrari...and so on. The point as related to sharpies and boat design is that as long as they do the work they were intended to it hardly makes sense to bash them for not doing more or even wishing they could.
>
> Bob
>
>http://boatbits.blogspot.com/
>http://fishingundersail.blogspot.com/
>http://islandgourmand.blogspot.com/
>
Amongst the hard-core critics of sharpies - none in
this forum it seems - what is too often overlooked is what Bob Wise just touched
upon. We've called it 'chine-sailing' - a different perspective on the
eddy issue.
Particularly in super-shallow waters, nothing will 'hang on' as well as a hard chine - unrounded. When no board can be down deeply enough to be particularly effective, the hard chine will work for you.
Particularly in super-shallow waters, nothing will 'hang on' as well as a hard chine - unrounded. When no board can be down deeply enough to be particularly effective, the hard chine will work for you.
This is a major conceptual issues which drove
Phil's and our persistent focus on sharpies. Being able to armor that
chine with slightly protruding - more eddies! - steel-plate ballast is
a sweet side-effect.
When you see fiberglass or metal boats, production or custom, in shallow water near the beach, but all round/multi-chine underwater, you know they just about had to get there by power. Advertised 'Shallow Draft' does not mean you can sail in shallow waters... Which closes off many waters and constitutes a safety-challenge, as there may well be times when 'chine-sailing' is the only thing between you and a leeshore.
That is why typically Phil's Barge-Yachts have a long shallow keel below the free-flow hullshape to allow some 'traction. Still, while aesthetically beautiful and 'test-tank'-/CFD-correct in their no-chine flow-pattern, they may for coastal cruising utility still be less desirable since they can not be armored at the turn of the bilge to casually explore the shallows under sail or race across them in a gale towards a sheltered harbor.
Between simplicity of construction, ability to massively armor the bottom and chine for routine shallow-water cruising and daily grounding out, plus the happy addition of foam-plate for insulation (multi-season habitability) and the option of building into a plywood-sharpie 'sinking-resistance' via enough foam and ply, there is not much that can compete conceptually and practically with a properly-proportioned sharpie cruiser, especially one with the vee-nose or modified cutwater-nose. We thought/think they are a rigor.
When you see fiberglass or metal boats, production or custom, in shallow water near the beach, but all round/multi-chine underwater, you know they just about had to get there by power. Advertised 'Shallow Draft' does not mean you can sail in shallow waters... Which closes off many waters and constitutes a safety-challenge, as there may well be times when 'chine-sailing' is the only thing between you and a leeshore.
That is why typically Phil's Barge-Yachts have a long shallow keel below the free-flow hullshape to allow some 'traction. Still, while aesthetically beautiful and 'test-tank'-/CFD-correct in their no-chine flow-pattern, they may for coastal cruising utility still be less desirable since they can not be armored at the turn of the bilge to casually explore the shallows under sail or race across them in a gale towards a sheltered harbor.
Between simplicity of construction, ability to massively armor the bottom and chine for routine shallow-water cruising and daily grounding out, plus the happy addition of foam-plate for insulation (multi-season habitability) and the option of building into a plywood-sharpie 'sinking-resistance' via enough foam and ply, there is not much that can compete conceptually and practically with a properly-proportioned sharpie cruiser, especially one with the vee-nose or modified cutwater-nose. We thought/think they are a rigor.
----- Original Message -----From:loosemoosefilmworksSent:Wednesday, January 05, 2011 9:43 AMSubject:[bolger] Re: Bolger on sharpies
We should not lose sight of reality in the face of theoretical conjecture...
Our Loose Moose (a Jessie Cooper) and Loose Moose 2, I suppose, could have had a bit better performing hull shape and when we were talking with Phil at the beginning of the Loose Moose 2 project I suggested that if I were to cold mold the chine that we'd be a fair bit slippery through the water and faster is no bad thing. Phil wrote back and agreed that the result would deliver a faster hull but also, in the grand scheme of things, seriously hamper windward ability. Sort of a one step forward and two steps back situation.
The thing is, Loose Moose and Loose Moose 2 sailed so well you never found yourself wishing you had a more efficient hull form because the one you had did just fine (thank you very much Mr Bolger) and while I am sure a more refined and engineered hull form would have been a bit faster, what would be the point?
My all time favorite VW advertisement (and if anyone knows of a copy floating around I am looking for one)where the point was made that the VW bug had four wheels... Just like the Rolls Royce, did 55MPH in a 55MPH zone just like the Ferrari...and so on. The point as related to sharpies and boat design is that as long as they do the work they were intended to it hardly makes sense to bash them for not doing more or even wishing they could.
Bob
http://boatbits.blogspot.com/
http://fishingundersail.blogspot.com/
http://islandgourmand.blogspot.com/
On Wed, Jan 5, 2011 at 6:43 AM, loosemoosefilmworks
<loosemoosefilmworks@...> wrote:
benefits worth mentioning:
1) Increased buoyancy, which means increased ballast without increased
draft. More ballast is very a good thing when tacking a sailboat.
2) The "square corners" inside the boat make for a roomy boat.
<loosemoosefilmworks@...> wrote:
> Phil wrote back and agreed that the result would deliver a faster hull but also, in the grand scheme of things, seriously hamper windward ability.Not to mention, the square chine have a couple other significant
benefits worth mentioning:
1) Increased buoyancy, which means increased ballast without increased
draft. More ballast is very a good thing when tacking a sailboat.
2) The "square corners" inside the boat make for a roomy boat.
Amen!
--- Inbolger@yahoogroups.com, "loosemoosefilmworks" <loosemoosefilmworks@...> wrote:
>
>
> We should not lose sight of reality in the face of theoretical conjecture...
>
> Our Loose Moose (a Jessie Cooper) and Loose Moose 2, I suppose, could have had a bit better performing hull shape and when we were talking with Phil at the beginning of the Loose Moose 2 project I suggested that if I were to cold mold the chine that we'd be a fair bit slippery through the water and faster is no bad thing. Phil wrote back and agreed that the result would deliver a faster hull but also, in the grand scheme of things, seriously hamper windward ability. Sort of a one step forward and two steps back situation.
>
> The thing is, Loose Moose and Loose Moose 2 sailed so well you never found yourself wishing you had a more efficient hull form because the one you had did just fine (thank you very much Mr Bolger) and while I am sure a more refined and engineered hull form would have been a bit faster, what would be the point?
>
> My all time favorite VW advertisement (and if anyone knows of a copy floating around I am looking for one)where the point was made that the VW bug had four wheels... Just like the Rolls Royce, did 55MPH in a 55MPH zone just like the Ferrari...and so on. The point as related to sharpies and boat design is that as long as they do the work they were intended to it hardly makes sense to bash them for not doing more or even wishing they could.
>
> Bob
>
>http://boatbits.blogspot.com/
>http://fishingundersail.blogspot.com/
>http://islandgourmand.blogspot.com/
>
We should not lose sight of reality in the face of theoretical conjecture...
Our Loose Moose (a Jessie Cooper) and Loose Moose 2, I suppose, could have had a bit better performing hull shape and when we were talking with Phil at the beginning of the Loose Moose 2 project I suggested that if I were to cold mold the chine that we'd be a fair bit slippery through the water and faster is no bad thing. Phil wrote back and agreed that the result would deliver a faster hull but also, in the grand scheme of things, seriously hamper windward ability. Sort of a one step forward and two steps back situation.
The thing is, Loose Moose and Loose Moose 2 sailed so well you never found yourself wishing you had a more efficient hull form because the one you had did just fine (thank you very much Mr Bolger) and while I am sure a more refined and engineered hull form would have been a bit faster, what would be the point?
My all time favorite VW advertisement (and if anyone knows of a copy floating around I am looking for one)where the point was made that the VW bug had four wheels... Just like the Rolls Royce, did 55MPH in a 55MPH zone just like the Ferrari...and so on. The point as related to sharpies and boat design is that as long as they do the work they were intended to it hardly makes sense to bash them for not doing more or even wishing they could.
Bob
http://boatbits.blogspot.com/
http://fishingundersail.blogspot.com/
http://islandgourmand.blogspot.com/
Our Loose Moose (a Jessie Cooper) and Loose Moose 2, I suppose, could have had a bit better performing hull shape and when we were talking with Phil at the beginning of the Loose Moose 2 project I suggested that if I were to cold mold the chine that we'd be a fair bit slippery through the water and faster is no bad thing. Phil wrote back and agreed that the result would deliver a faster hull but also, in the grand scheme of things, seriously hamper windward ability. Sort of a one step forward and two steps back situation.
The thing is, Loose Moose and Loose Moose 2 sailed so well you never found yourself wishing you had a more efficient hull form because the one you had did just fine (thank you very much Mr Bolger) and while I am sure a more refined and engineered hull form would have been a bit faster, what would be the point?
My all time favorite VW advertisement (and if anyone knows of a copy floating around I am looking for one)where the point was made that the VW bug had four wheels... Just like the Rolls Royce, did 55MPH in a 55MPH zone just like the Ferrari...and so on. The point as related to sharpies and boat design is that as long as they do the work they were intended to it hardly makes sense to bash them for not doing more or even wishing they could.
Bob
http://boatbits.blogspot.com/
http://fishingundersail.blogspot.com/
http://islandgourmand.blogspot.com/
I get the idea in your laudable experiment that pressure is related to angle of incidence, but still wonder about that hypothesis. It's obvious from experience that varying the angle of a plate held in a stream of water from a hose, say, varies the pressure felt on the plate. In the minds eye we can see a stream of water particles hitting the plate with more or less glancing blows - the more acute their angle of incidence the less energy imparted to the plate - AND we think we see from which direction the water particles come forced from the hose. However along with the three dimensional boat and trim changes there are pressure differentials linked with the shape, depth, and speed of the gravity affected wave train about the boat, and pressure differentials created by laminar and turbulent flows over the immersed hull surface, all affected by the shape, trim, and orientation of the boat... Make the plate a streamlined foil in the hose experiment and the pressure change felt may actually reverse and increase below some acute angle of incidence and the flow circulate somewhat... Still, as you found, for a given hull I'm sure altering the apparent angle of incidence of the forward bottom has a noteable effect on observed cross-chine flow. Even so, PCB used hulls of differing 3D shape about the bow to make his point plain about another shape ideally of equal profle and plan chine line curvature. However, even there all is not equal for that equally curved ideal Advanced Sharpie bow when the fore and aft trim angle is altered whilst the boat remains in level trim athwartships: It may seem apparent that the equally curved sides and bottom panels present an equal angle of incidence to the water flow and so prevent cross chine flows... but what else has changed at the bow? Hull COB and draft, noteably so, for the bottom narrows greatly towards the bow; and with that the relative wave train position, shape and height, and the hull surface flow paths - we might look to the stern wave too. If there's no cross chine flow at such lowered bow I suspect it's due to other complex factors in addition to the idealised billiard ball like apparent on-coming water flow striking at some further idealised angle of incidence with the bow panels.
It crosses the chine forward, one way or the other, or not at all, yes, but what else is water really doing unseen?
It crosses the chine forward, one way or the other, or not at all, yes, but what else is water really doing unseen?
--- Inbolger@yahoogroups.com, Paul Glassen <paul_glassen@...> wrote:
>
>
> I have been reading Phil Bolger's thoughts on sharpies for around 40 years. So sometime in the mid 1970s I decided to conduct an experiment to test his description of the behaviour of water flow around the chines of a hard chine hull. I owned a small 'flattie' rowing skiff, a classic rocker bottomed rowing boat, not an outboard. I thumb-tacked streamers along its chine. Then I tied it to a piling in a stream. I ballasted it so I could look over the side and see the streamers along the chine while the boat was still sitting flat in the water from side to side. Then I moved myself and other weight fore and aft to alter the bottom's angle of incidence with the stream's flow.
>
> I think this matter of the water's angle of incidence with the various parts of the hull is key. My understanding is that Phil was talking about relative angles of incidence, saying that in a typical historical sharpie the angle of incidence is greater on the sides than on the bottom, causing more pressure on the sides and hence leading the water to "escape" to the lower pressure area of the bottom.
>
> The results of my experiment were consistent with this understanding. The side's angle of incidence with the flow of the stream was constant, determined by the boat's shape. But I altered the bottom's angle of incidence by trimming the bow up and down. Sure enough, with the bow low, creating a low angle of incidence on the bottom, the streamers flowed down from the side under the bottom. With the bow high, increasing the bottom's angle of incidence and pressure, the streamers first flowed along the chine and, with increased bow height/bottom angle of incidence, the streamers flowed up the sides.
>
> I don't think this idea is limited to sharpies in any way. On a fully moulded, rounded hull, the water will flow from high pressure areas to low. And the pressure will be determined by angle of incidence. The ideal would be for the shape to create such equal pressure that the water would flow from the bow to the stern by the shortest, most direct route. This, of course applies to the stern's angle of departure as well as the bow's angle of incidence. Both create increasing or decreasing pressure.
>
> Anyway, that's my two cents after a lifetime of thinking about boat shapes. (Well, maybe 60 years of my lifetime. I built my first boat at 11, but had been thinking about them for a few years before that. Can't quite say for sure that I was thinking about them from the day I was born, although my father was a boatman before me.)
>
> Paul Glassen
> Vancouver Island, British Columbia
>
My mind turns to mush when it comes to this stuff. I enjoy reading it, but all I can really say is that my Oldshoe's pointy end goes where I want it to, most of the time and very nicely at that! Thank You Phil!
Dennis
OldShoe "Pearl"
Bellingham, Washington
Dennis
OldShoe "Pearl"
Bellingham, Washington
--- Inbolger@yahoogroups.com, Paul Glassen <paul_glassen@...> wrote:
>
>
> I have been reading Phil Bolger's thoughts on sharpies for around 40 years. So sometime in the mid 1970s I decided to conduct an experiment to test his description of the behaviour of water flow around the chines of a hard chine hull. I owned a small 'flattie' rowing skiff, a classic rocker bottomed rowing boat, not an outboard. I thumb-tacked streamers along its chine. Then I tied it to a piling in a stream. I ballasted it so I could look over the side and see the streamers along the chine while the boat was still sitting flat in the water from side to side. Then I moved myself and other weight fore and aft to alter the bottom's angle of incidence with the stream's flow.
>
> I think this matter of the water's angle of incidence with the various parts of the hull is key. My understanding is that Phil was talking about relative angles of incidence, saying that in a typical historical sharpie the angle of incidence is greater on the sides than on the bottom, causing more pressure on the sides and hence leading the water to "escape" to the lower pressure area of the bottom.
>
> The results of my experiment were consistent with this understanding. The side's angle of incidence with the flow of the stream was constant, determined by the boat's shape. But I altered the bottom's angle of incidence by trimming the bow up and down. Sure enough, with the bow low, creating a low angle of incidence on the bottom, the streamers flowed down from the side under the bottom. With the bow high, increasing the bottom's angle of incidence and pressure, the streamers first flowed along the chine and, with increased bow height/bottom angle of incidence, the streamers flowed up the sides.
>
> I don't think this idea is limited to sharpies in any way. On a fully moulded, rounded hull, the water will flow from high pressure areas to low. And the pressure will be determined by angle of incidence. The ideal would be for the shape to create such equal pressure that the water would flow from the bow to the stern by the shortest, most direct route. This, of course applies to the stern's angle of departure as well as the bow's angle of incidence. Both create increasing or decreasing pressure.
>
> Anyway, that's my two cents after a lifetime of thinking about boat shapes. (Well, maybe 60 years of my lifetime. I built my first boat at 11, but had been thinking about them for a few years before that. Can't quite say for sure that I was thinking about them from the day I was born, although my father was a boatman before me.)
>
> Paul Glassen
> Vancouver Island, British Columbia
>
I have been reading Phil Bolger's thoughts on sharpies for around 40 years. So sometime in the mid 1970s I decided to conduct an experiment to test his description of the behaviour of water flow around the chines of a hard chine hull. I owned a small 'flattie' rowing skiff, a classic rocker bottomed rowing boat, not an outboard. I thumb-tacked streamers along its chine. Then I tied it to a piling in a stream. I ballasted it so I could look over the side and see the streamers along the chine while the boat was still sitting flat in the water from side to side. Then I moved myself and other weight fore and aft to alter the bottom's angle of incidence with the stream's flow.
I think this matter of the water's angle of incidence with the various parts of the hull is key. My understanding is that Phil was talking aboutrelativeangles of incidence, saying that in a typical historical sharpie the angle of incidence is greater on the sides than on the bottom, causing more pressure on the sides and hence leading the water to "escape" to the lower pressure area of the bottom.
The results of my experiment were consistent with this understanding. The side's angle of incidence with the flow of the stream was constant, determined by the boat's shape. But I altered the bottom's angle of incidence by trimming the bow up and down. Sure enough, with the bow low, creating a low angle of incidence on the bottom, the streamers flowed down from the side under the bottom. With the bow high, increasing the bottom's angle of incidence and pressure, the streamers first flowed along the chine and, with increased bow height/bottom angle of incidence, the streamers flowed up the sides.
I don't think this idea is limited to sharpies in any way. On a fully moulded, rounded hull, the water will flow from high pressure areas to low. And the pressure will be determined by angle of incidence. The ideal would be for the shape to create such equal pressure that the water would flow from the bow to the stern by the shortest, most direct route. This, of course applies to the stern's angle of departure as well as the bow's angle of incidence. Both create increasing or decreasing pressure.
Anyway, that's my two cents after a lifetime of thinking about boat shapes. (Well, maybe 60 years of my lifetime. I built my first boat at 11, but had been thinking about them for a few years before that. Can't quite say for sure that I was thinking about them from the day I was born, although my father was a boatman before me.)
Paul Glassen
Vancouver Island, British Columbia
I think this matter of the water's angle of incidence with the various parts of the hull is key. My understanding is that Phil was talking aboutrelativeangles of incidence, saying that in a typical historical sharpie the angle of incidence is greater on the sides than on the bottom, causing more pressure on the sides and hence leading the water to "escape" to the lower pressure area of the bottom.
The results of my experiment were consistent with this understanding. The side's angle of incidence with the flow of the stream was constant, determined by the boat's shape. But I altered the bottom's angle of incidence by trimming the bow up and down. Sure enough, with the bow low, creating a low angle of incidence on the bottom, the streamers flowed down from the side under the bottom. With the bow high, increasing the bottom's angle of incidence and pressure, the streamers first flowed along the chine and, with increased bow height/bottom angle of incidence, the streamers flowed up the sides.
I don't think this idea is limited to sharpies in any way. On a fully moulded, rounded hull, the water will flow from high pressure areas to low. And the pressure will be determined by angle of incidence. The ideal would be for the shape to create such equal pressure that the water would flow from the bow to the stern by the shortest, most direct route. This, of course applies to the stern's angle of departure as well as the bow's angle of incidence. Both create increasing or decreasing pressure.
Anyway, that's my two cents after a lifetime of thinking about boat shapes. (Well, maybe 60 years of my lifetime. I built my first boat at 11, but had been thinking about them for a few years before that. Can't quite say for sure that I was thinking about them from the day I was born, although my father was a boatman before me.)
Paul Glassen
Vancouver Island, British Columbia