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Hull Flexing
I had a odd experience yesterday. I went to the boat to finish winterizing, and saw my
neighbor trying to get into his boat, a Prout 37 (which, BTW, has done 3 trans-Atlantic crossings). The companionway door was latched and locked - he was baffled because the door had never latched in his experience (he's had the boat a year and always locked with an external padlock). After a while we were able to pry it open and figure out what had happened. On Thursday the mast had been pulled. This seems to have relaxed the hull enough that the latch, which had not recently engaged, now caught the latch plate. We estimate maybe 1/16 inch of flexing. Before you jump on the fact that a catamaran hull had a bit of flex, here's what the owner said "I surprised there would be any flex at all - but my old C&C 37 flexed so much when we unrigged her that it opened a deck leak." |
Hull Flexing
Check the jack stands. Some fool probably has the ones in the
middle way too tight and doing most of the work and bending the boat in the process. S.Simon "Jeff Morris" wrote in message ... I had a odd experience yesterday. I went to the boat to finish winterizing, and saw my neighbor trying to get into his boat, a Prout 37 (which, BTW, has done 3 trans-Atlantic crossings). The companionway door was latched and locked - he was baffled because the door had never latched in his experience (he's had the boat a year and always locked with an external padlock). After a while we were able to pry it open and figure out what had happened. On Thursday the mast had been pulled. This seems to have relaxed the hull enough that the latch, which had not recently engaged, now caught the latch plate. We estimate maybe 1/16 inch of flexing. Before you jump on the fact that a catamaran hull had a bit of flex, here's what the owner said "I surprised there would be any flex at all - but my old C&C 37 flexed so much when we unrigged her that it opened a deck leak." |
Hull Flexing
Its a catamaran - it can rest on its two keels. Prouts can be stashed like that because
the keels are solid. My keels, however, are "sacrificial" so its best to jack under the bridge, supporting most of the weight under the bulkheads: http://www.sv-loki.com/Along_the_Way/UnderBelly.jpg "Simple Simon" wrote in message ... Check the jack stands. Some fool probably has the ones in the middle way too tight and doing most of the work and bending the boat in the process. S.Simon "Jeff Morris" wrote in message ... I had a odd experience yesterday. I went to the boat to finish winterizing, and saw my neighbor trying to get into his boat, a Prout 37 (which, BTW, has done 3 trans-Atlantic crossings). The companionway door was latched and locked - he was baffled because the door had never latched in his experience (he's had the boat a year and always locked with an external padlock). After a while we were able to pry it open and figure out what had happened. On Thursday the mast had been pulled. This seems to have relaxed the hull enough that the latch, which had not recently engaged, now caught the latch plate. We estimate maybe 1/16 inch of flexing. Before you jump on the fact that a catamaran hull had a bit of flex, here's what the owner said "I surprised there would be any flex at all - but my old C&C 37 flexed so much when we unrigged her that it opened a deck leak." |
Hull Flexing
I see the problem. Those jack stands blocking up the
bridge deck are doing just the opposite of what that area of the boat is supposed to do. If the stands are taking too much weight the hulls are sort of hanging from the bridge deck. In the water the hulls support the bridge deck. In the water viewed from the front the bridge deck would have a tendency to be curved down a little in the center portions. Jacked up as it shows the bridge deck would be curved the opposite way. This would warp the house in an abnormal manner. S.Simon "Jeff Morris" wrote in message ... Its a catamaran - it can rest on its two keels. Prouts can be stashed like that because the keels are solid. My keels, however, are "sacrificial" so its best to jack under the bridge, supporting most of the weight under the bulkheads: http://www.sv-loki.com/Along_the_Way/UnderBelly.jpg "Simple Simon" wrote in message ... Check the jack stands. Some fool probably has the ones in the middle way too tight and doing most of the work and bending the boat in the process. S.Simon "Jeff Morris" wrote in message ... I had a odd experience yesterday. I went to the boat to finish winterizing, and saw my neighbor trying to get into his boat, a Prout 37 (which, BTW, has done 3 trans-Atlantic crossings). The companionway door was latched and locked - he was baffled because the door had never latched in his experience (he's had the boat a year and always locked with an external padlock). After a while we were able to pry it open and figure out what had happened. On Thursday the mast had been pulled. This seems to have relaxed the hull enough that the latch, which had not recently engaged, now caught the latch plate. We estimate maybe 1/16 inch of flexing. Before you jump on the fact that a catamaran hull had a bit of flex, here's what the owner said "I surprised there would be any flex at all - but my old C&C 37 flexed so much when we unrigged her that it opened a deck leak." |
Hull Flexing
Doesn't really matter what size the boat is, you will get some degree of
"flex", especially when you remove it from the water and put it on a hard stand. BG you want to see flex, you should watch and listen to a large tanker at sea, or watch one go from hog to sag when loading. otn Jeff Morris wrote: I had a odd experience yesterday. I went to the boat to finish winterizing, and saw my neighbor trying to get into his boat, a Prout 37 (which, BTW, has done 3 trans-Atlantic crossings). The companionway door was latched and locked - he was baffled because the door had never latched in his experience (he's had the boat a year and always locked with an external padlock). After a while we were able to pry it open and figure out what had happened. On Thursday the mast had been pulled. This seems to have relaxed the hull enough that the latch, which had not recently engaged, now caught the latch plate. We estimate maybe 1/16 inch of flexing. Before you jump on the fact that a catamaran hull had a bit of flex, here's what the owner said "I surprised there would be any flex at all - but my old C&C 37 flexed so much when we unrigged her that it opened a deck leak." |
Hull Flexing
Again, allow me to reiterate. This is a sailing newsgroup.
We talk sailing yachts here. Why do you keep butting in with your motor vessel references which are not relevant? S.Simon "otnmbrd" wrote in message ink.net... Doesn't really matter what size the boat is, you will get some degree of "flex", especially when you remove it from the water and put it on a hard stand. BG you want to see flex, you should watch and listen to a large tanker at sea, or watch one go from hog to sag when loading. otn Jeff Morris wrote: I had a odd experience yesterday. I went to the boat to finish winterizing, and saw my neighbor trying to get into his boat, a Prout 37 (which, BTW, has done 3 trans-Atlantic crossings). The companionway door was latched and locked - he was baffled because the door had never latched in his experience (he's had the boat a year and always locked with an external padlock). After a while we were able to pry it open and figure out what had happened. On Thursday the mast had been pulled. This seems to have relaxed the hull enough that the latch, which had not recently engaged, now caught the latch plate. We estimate maybe 1/16 inch of flexing. Before you jump on the fact that a catamaran hull had a bit of flex, here's what the owner said "I surprised there would be any flex at all - but my old C&C 37 flexed so much when we unrigged her that it opened a deck leak." |
Hull Flexing
Your theory might have merit except for a few details:
First of all, the pictures are of my boat, while the problem was different boat, a Prout 37. The Prout has a third, central hull, called a "nacelle," and it is impractical to support like mine. It is sitting on its keels. At first, I wondered if the center of the Prout had sagged and should be supported, but we concluded that in fact the center had risen when the weight and stress of the mast had been removed. My boat is supported according to the factory specs. Although the keels can support the hull for a limited period, they are not intended to support the hull for extended periods. Since the three timbers are directly un the three bulkheads, the hull is support with no flexing. "Simple Simon" wrote in message ... I see the problem. Those jack stands blocking up the bridge deck are doing just the opposite of what that area of the boat is supposed to do. If the stands are taking too much weight the hulls are sort of hanging from the bridge deck. In the water the hulls support the bridge deck. In the water viewed from the front the bridge deck would have a tendency to be curved down a little in the center portions. Jacked up as it shows the bridge deck would be curved the opposite way. This would warp the house in an abnormal manner. S.Simon "Jeff Morris" wrote in message ... Its a catamaran - it can rest on its two keels. Prouts can be stashed like that because the keels are solid. My keels, however, are "sacrificial" so its best to jack under the bridge, supporting most of the weight under the bulkheads: http://www.sv-loki.com/Along_the_Way/UnderBelly.jpg "Simple Simon" wrote in message ... Check the jack stands. Some fool probably has the ones in the middle way too tight and doing most of the work and bending the boat in the process. S.Simon "Jeff Morris" wrote in message ... I had a odd experience yesterday. I went to the boat to finish winterizing, and saw my neighbor trying to get into his boat, a Prout 37 (which, BTW, has done 3 trans-Atlantic crossings). The companionway door was latched and locked - he was baffled because the door had never latched in his experience (he's had the boat a year and always locked with an external padlock). After a while we were able to pry it open and figure out what had happened. On Thursday the mast had been pulled. This seems to have relaxed the hull enough that the latch, which had not recently engaged, now caught the latch plate. We estimate maybe 1/16 inch of flexing. Before you jump on the fact that a catamaran hull had a bit of flex, here's what the owner said "I surprised there would be any flex at all - but my old C&C 37 flexed so much when we unrigged her that it opened a deck leak." |
Hull Flexing
Subject: Hull Flexing
From: "Simple Simon" Date: 11/09/2003 16:38 Pacific Standard Time Message-id: Again, allow me to reiterate. This is a sailing newsgroup. We talk sailing yachts here. Why do you keep butting in with your motor vessel references which are not relevant? S.Simon If you had a lick of common sense, you'd have noted the general, but related sense to his comments. Shen |
Hull Flexing
Then it sounds like the Prout might be designed to incorporate
the rigging into the total package to stiffen things up. That's a problem with catamarans - the downward force of mast and rigging places maximum loading on the center of the bridge deck as there is no hull there into which to step the mast and loading. So one can easily picture the hulls being pulled up by the rigging while the center of the bridge deck is being pushed down. When their mast and rigging forces are removed the bridge deck can then assume a more upward position causing the house to warp somewhat. This might cause the doors to jam, etc. It fits my theory about how a properly stayed vessel is a much stronger system then say a Nonsuch with an unstayed mast. S.Simon "Jeff Morris" wrote in message ... Your theory might have merit except for a few details: First of all, the pictures are of my boat, while the problem was different boat, a Prout 37. The Prout has a third, central hull, called a "nacelle," and it is impractical to support like mine. It is sitting on its keels. At first, I wondered if the center of the Prout had sagged and should be supported, but we concluded that in fact the center had risen when the weight and stress of the mast had been removed. My boat is supported according to the factory specs. Although the keels can support the hull for a limited period, they are not intended to support the hull for extended periods. Since the three timbers are directly un the three bulkheads, the hull is support with no flexing. "Simple Simon" wrote in message ... I see the problem. Those jack stands blocking up the bridge deck are doing just the opposite of what that area of the boat is supposed to do. If the stands are taking too much weight the hulls are sort of hanging from the bridge deck. In the water the hulls support the bridge deck. In the water viewed from the front the bridge deck would have a tendency to be curved down a little in the center portions. Jacked up as it shows the bridge deck would be curved the opposite way. This would warp the house in an abnormal manner. S.Simon "Jeff Morris" wrote in message ... Its a catamaran - it can rest on its two keels. Prouts can be stashed like that because the keels are solid. My keels, however, are "sacrificial" so its best to jack under the bridge, supporting most of the weight under the bulkheads: http://www.sv-loki.com/Along_the_Way/UnderBelly.jpg "Simple Simon" wrote in message ... Check the jack stands. Some fool probably has the ones in the middle way too tight and doing most of the work and bending the boat in the process. S.Simon "Jeff Morris" wrote in message ... I had a odd experience yesterday. I went to the boat to finish winterizing, and saw my neighbor trying to get into his boat, a Prout 37 (which, BTW, has done 3 trans-Atlantic crossings). The companionway door was latched and locked - he was baffled because the door had never latched in his experience (he's had the boat a year and always locked with an external padlock). After a while we were able to pry it open and figure out what had happened. On Thursday the mast had been pulled. This seems to have relaxed the hull enough that the latch, which had not recently engaged, now caught the latch plate. We estimate maybe 1/16 inch of flexing. Before you jump on the fact that a catamaran hull had a bit of flex, here's what the owner said "I surprised there would be any flex at all - but my old C&C 37 flexed so much when we unrigged her that it opened a deck leak." |
Hull Flexing
otnmbrd wrote:
Doesn't really matter what size the boat is, you will get some degree of "flex", especially when you remove it from the water and put it on a hard stand. BG you want to see flex, you should watch and listen to a large tanker at sea, or watch one go from hog to sag when loading. Sure. Why else would they build expansion joints into the upper decks of big (or even medium-sized) ships? The only way to have zero flex would be to have literally infinite rigidity. The question is, how much is too much, and how much is marginally greater rigidity worth the other sacrifices made to increase it? 1/16" doesn't sound like a problem to me, although the latch sounds like a PITA. Another issue is that fiberglass does lose a bit of torsional strength as it flexes many times... just like any other material. The nice thing about fiberglass is that it has a very high number of load & flex cycles to fatigue failure. Great engineering material, pity it's so heavy. I remember reading about a New Orleans Marine hotshot racing boat built back in the 1980s, which had a hull & deck of uncored glass & mat with a subimposed grid of straight S-glass. Everybody guffawed and said "Those hicks sure don't know how to build racing boats, shoulda used foam core" but the builder shrugged and said that they measured the bend in the hull/deck with 15,000# tension on the backstay.... it was 4 thousands of an inch.... Fresh Breezes- Doug King |
Hull Flexing
It fits my theory about how a properly stayed vessel is a
much stronger system then say a Nonsuch with an unstayed mast. How many rig failures can you prove for the Nonsuch? Some theory! RB |
Hull Flexing
One more point - on a Prout the mast is stepped aft, supported by the same bulkhead that the door is
in. In fact, the latch is about 2 feet below where the butt of the mast was. This is why we concluded the flexing was caused by the rig. As to your claim that the rig adds strength, this may be so, but it doesn't mean that a Nonsuch is flimsy for lack of a rig. Perhaps they are overbuilt to compensate, but they are very strong, solid boats. -- -jeff "Simple Simon" wrote in message ... Then it sounds like the Prout might be designed to incorporate the rigging into the total package to stiffen things up. That's a problem with catamarans - the downward force of mast and rigging places maximum loading on the center of the bridge deck as there is no hull there into which to step the mast and loading. So one can easily picture the hulls being pulled up by the rigging while the center of the bridge deck is being pushed down. When their mast and rigging forces are removed the bridge deck can then assume a more upward position causing the house to warp somewhat. This might cause the doors to jam, etc. It fits my theory about how a properly stayed vessel is a much stronger system then say a Nonsuch with an unstayed mast. S.Simon "Jeff Morris" wrote in message ... Your theory might have merit except for a few details: First of all, the pictures are of my boat, while the problem was different boat, a Prout 37. The Prout has a third, central hull, called a "nacelle," and it is impractical to support like mine. It is sitting on its keels. At first, I wondered if the center of the Prout had sagged and should be supported, but we concluded that in fact the center had risen when the weight and stress of the mast had been removed. My boat is supported according to the factory specs. Although the keels can support the hull for a limited period, they are not intended to support the hull for extended periods. Since the three timbers are directly un the three bulkheads, the hull is support with no flexing. "Simple Simon" wrote in message ... I see the problem. Those jack stands blocking up the bridge deck are doing just the opposite of what that area of the boat is supposed to do. If the stands are taking too much weight the hulls are sort of hanging from the bridge deck. In the water the hulls support the bridge deck. In the water viewed from the front the bridge deck would have a tendency to be curved down a little in the center portions. Jacked up as it shows the bridge deck would be curved the opposite way. This would warp the house in an abnormal manner. S.Simon "Jeff Morris" wrote in message ... Its a catamaran - it can rest on its two keels. Prouts can be stashed like that because the keels are solid. My keels, however, are "sacrificial" so its best to jack under the bridge, supporting most of the weight under the bulkheads: http://www.sv-loki.com/Along_the_Way/UnderBelly.jpg "Simple Simon" wrote in message ... Check the jack stands. Some fool probably has the ones in the middle way too tight and doing most of the work and bending the boat in the process. S.Simon "Jeff Morris" wrote in message ... I had a odd experience yesterday. I went to the boat to finish winterizing, and saw my neighbor trying to get into his boat, a Prout 37 (which, BTW, has done 3 trans-Atlantic crossings). The companionway door was latched and locked - he was baffled because the door had never latched in his experience (he's had the boat a year and always locked with an external padlock). After a while we were able to pry it open and figure out what had happened. On Thursday the mast had been pulled. This seems to have relaxed the hull enough that the latch, which had not recently engaged, now caught the latch plate. We estimate maybe 1/16 inch of flexing. Before you jump on the fact that a catamaran hull had a bit of flex, here's what the owner said "I surprised there would be any flex at all - but my old C&C 37 flexed so much when we unrigged her that it opened a deck leak." |
Hull Flexing
As to your claim that the rig adds strength, this may be so, but it doesn't
mean that a Nonsuch is flimsy for lack of a rig. Perhaps they are overbuilt to compensate, but they are very strong, solid boats. No way! Let's wait to see Neal's links to rig failures for Freedom and Nonsuch. I'm sure he knows what he's talking about! RB |
Hull Flexing
Another theory pulled from the ass of Simp. Over 2 thousand Nonsuches
and Freedoms produced and still in service, 20 plus years after their introduction. You should be able to find the data to prove your "theory". Step up, man or shut up. On Mon, 10 Nov 2003 00:10:49 -0500, "Simple Simon" wrote: Then it sounds like the Prout might be designed to incorporate the rigging into the total package to stiffen things up. That's a problem with catamarans - the downward force of mast and rigging places maximum loading on the center of the bridge deck as there is no hull there into which to step the mast and loading. So one can easily picture the hulls being pulled up by the rigging while the center of the bridge deck is being pushed down. When their mast and rigging forces are removed the bridge deck can then assume a more upward position causing the house to warp somewhat. This might cause the doors to jam, etc. It fits my theory about how a properly stayed vessel is a much stronger system then say a Nonsuch with an unstayed mast. S.Simon "Jeff Morris" wrote in message ... Your theory might have merit except for a few details: First of all, the pictures are of my boat, while the problem was different boat, a Prout 37. The Prout has a third, central hull, called a "nacelle," and it is impractical to support like mine. It is sitting on its keels. At first, I wondered if the center of the Prout had sagged and should be supported, but we concluded that in fact the center had risen when the weight and stress of the mast had been removed. My boat is supported according to the factory specs. Although the keels can support the hull for a limited period, they are not intended to support the hull for extended periods. Since the three timbers are directly un the three bulkheads, the hull is support with no flexing. "Simple Simon" wrote in message ... I see the problem. Those jack stands blocking up the bridge deck are doing just the opposite of what that area of the boat is supposed to do. If the stands are taking too much weight the hulls are sort of hanging from the bridge deck. In the water the hulls support the bridge deck. In the water viewed from the front the bridge deck would have a tendency to be curved down a little in the center portions. Jacked up as it shows the bridge deck would be curved the opposite way. This would warp the house in an abnormal manner. S.Simon "Jeff Morris" wrote in message ... Its a catamaran - it can rest on its two keels. Prouts can be stashed like that because the keels are solid. My keels, however, are "sacrificial" so its best to jack under the bridge, supporting most of the weight under the bulkheads: http://www.sv-loki.com/Along_the_Way/UnderBelly.jpg "Simple Simon" wrote in message ... Check the jack stands. Some fool probably has the ones in the middle way too tight and doing most of the work and bending the boat in the process. S.Simon "Jeff Morris" wrote in message ... I had a odd experience yesterday. I went to the boat to finish winterizing, and saw my neighbor trying to get into his boat, a Prout 37 (which, BTW, has done 3 trans-Atlantic crossings). The companionway door was latched and locked - he was baffled because the door had never latched in his experience (he's had the boat a year and always locked with an external padlock). After a while we were able to pry it open and figure out what had happened. On Thursday the mast had been pulled. This seems to have relaxed the hull enough that the latch, which had not recently engaged, now caught the latch plate. We estimate maybe 1/16 inch of flexing. Before you jump on the fact that a catamaran hull had a bit of flex, here's what the owner said "I surprised there would be any flex at all - but my old C&C 37 flexed so much when we unrigged her that it opened a deck leak." |
Hull Flexing
Another theory pulled from the ass of Simp. Over 2 thousand Nonsuches
and Freedoms produced and still in service, 20 plus years after their introduction. You should be able to find the data to prove your "theory". Step up, man or shut up. I spoke to a Freedom rep at a show and he said the only rig failures of Freedom's was ONE during a test prior to final production of the unstayed system. As fas as he knew, no rig failures among the production boats. I remember a friend telling me that a Nonsuch lost it's mast when it struck a bridge. Does that count? RB |
Hull Flexing
There was a story of a Nonsuch on a single handed trans-Atlantic. He had a serious
problem - I think the boom broke or fell - and decided to abandon the boat and take a ride on a freighter. About a year later the hull was spotted by a cruiser in South America; it was being used by local fishermen, without mast. The owner was tracked down, and he came and "bought" the hull, and had it refitted. BTW, while I think the Nonsuch is superb coastal cruiser, it does have limitations as a passagemaker. However, I still haven't found any documented stories of rig or hull failures or capsizes - only claims of a "friend of a friend heard once in a bar ..." jeff - member of the International Nonsuch Association for 8 years "Bobsprit" wrote in message ... Another theory pulled from the ass of Simp. Over 2 thousand Nonsuches and Freedoms produced and still in service, 20 plus years after their introduction. You should be able to find the data to prove your "theory". Step up, man or shut up. I spoke to a Freedom rep at a show and he said the only rig failures of Freedom's was ONE during a test prior to final production of the unstayed system. As fas as he knew, no rig failures among the production boats. I remember a friend telling me that a Nonsuch lost it's mast when it struck a bridge. Does that count? RB |
Hull Flexing
passagemaker. However, I still haven't found any documented stories of rig or
hull failures or capsizes - only claims of a "friend of a friend heard once in a bar ...." Jeff, I can put you in touch with the skipper who was involved in multiple capsizing on a Nonsuch. The story was covered on CBS news some years ago. The boat was lost when the owner panicked and tossed the hatchboards over the side. She had already rolled twice prior to this. Contact me direct and I'll give you his number. He currently works at city Island. He's doing a Miami delivery at the moment but will return in December. RB |
Hull Flexing
I'm not sure I want to hear this one, since I don't have a Nonsuch anymore, and wouldn't
use one for offshore purposes. However, the "capsize issue" is that the bad stability numbers imply that a Nonsuch might stay inverted. If your friend had multiple capsizes, this was not the case; he was doing 360's. Without hatchboards, this can be a critical situation. BTW, did they loose the rig? I certainly don't fault him for abandoning, but there's nothing in your brief account that reflects poorly on the vessel. "Bobsprit" wrote in message ... passagemaker. However, I still haven't found any documented stories of rig or hull failures or capsizes - only claims of a "friend of a friend heard once in a bar ..." Jeff, I can put you in touch with the skipper who was involved in multiple capsizing on a Nonsuch. The story was covered on CBS news some years ago. The boat was lost when the owner panicked and tossed the hatchboards over the side. She had already rolled twice prior to this. Contact me direct and I'll give you his number. He currently works at city Island. He's doing a Miami delivery at the moment but will return in December. RB |
Hull Flexing
About the only place I've seen "expansion joints", is on Navy ships
(which is not to say some passenger ships might have them). On a tanker, the only place you'll see them will be on catwalks and in piping (G can get downright squeaky). Tankers, being built with longitudinal framing, tend to bend more, in that direction. otn DSK wrote: otnmbrd wrote: Doesn't really matter what size the boat is, you will get some degree of "flex", especially when you remove it from the water and put it on a hard stand. BG you want to see flex, you should watch and listen to a large tanker at sea, or watch one go from hog to sag when loading. Sure. Why else would they build expansion joints into the upper decks of big (or even medium-sized) ships? |
Hull Flexing
4 thou. measured on the back of a boat? Complete BS.
Cheers MC DSK wrote: I remember reading about a New Orleans Marine hotshot racing boat built back in the 1980s, which had a hull & deck of uncored glass & mat with a subimposed grid of straight S-glass. Everybody guffawed and said "Those hicks sure don't know how to build racing boats, shoulda used foam core" but the builder shrugged and said that they measured the bend in the hull/deck with 15,000# tension on the backstay.... it was 4 thousands of an inch.... Fresh Breezes- Doug King |
Hull Flexing
Ever heard of temperature?
MC DSK wrote: Sure. Why else would they build expansion joints into the upper decks of big (or even medium-sized) ships? |
Hull Flexing
They are common in engineering in an pipe system that is exposed to wide
temperatuire fluctualtions. Cheers MC otnmbrd wrote: About the only place I've seen "expansion joints", is on Navy ships (which is not to say some passenger ships might have them). On a tanker, the only place you'll see them will be on catwalks and in piping (G can get downright squeaky). Tankers, being built with longitudinal framing, tend to bend more, in that direction. otn DSK wrote: otnmbrd wrote: Doesn't really matter what size the boat is, you will get some degree of "flex", especially when you remove it from the water and put it on a hard stand. BG you want to see flex, you should watch and listen to a large tanker at sea, or watch one go from hog to sag when loading. Sure. Why else would they build expansion joints into the upper decks of big (or even medium-sized) ships? |
Hull Flexing
The_navigator© wrote:
4 thou. measured on the back of a boat? Complete BS. "The Captain...cap n all" wrote: I would have thought so. AFAIK there was no reason to BS about it, the boat was a one-off and paid for. If I am interpreting the article about the boat correctly, the distortion was measured at the mid length along a straight from stem to center transom. If one is installing high powered hydraulics to control the rig, it makes sense to make the hull & deck structure as rigid as possible, within reasonable weight limits. I haven't seen any figures for the distortion measured on the newest IACC boats but the early 1990s boats had very high rig loads (10K kg and up) and very little (if any) distortion. Fresh Breezes- Doug King |
Hull Flexing
I'd say It's BS because boats are simply not that rigid and it's hard to
measure to an accuracy of 4 thou on big objects. The flexability of most boats is such that the side stays limit the spread of the hull as the backstay is tightened (this is naval architecture 101). Current rig tensions are much higher than they used to be. Even Ella has a backstay tension of 2,500 lbs when beating. Cheers MC DSK wrote: The_navigator© wrote: 4 thou. measured on the back of a boat? Complete BS. "The Captain...cap n all" wrote: I would have thought so. AFAIK there was no reason to BS about it, the boat was a one-off and paid for. If I am interpreting the article about the boat correctly, the distortion was measured at the mid length along a straight from stem to center transom. If one is installing high powered hydraulics to control the rig, it makes sense to make the hull & deck structure as rigid as possible, within reasonable weight limits. I haven't seen any figures for the distortion measured on the newest IACC boats but the early 1990s boats had very high rig loads (10K kg and up) and very little (if any) distortion. Fresh Breezes- Doug King |
Hull Flexing
On a tanker, Dresser couplings are used less for temperature
fluctuations, than for longitudinal flexing due to load and or working in a seaway. The same would apply to the flex joints that DSK was talking about. otn The_navigator© wrote: They are common in engineering in an pipe system that is exposed to wide temperatuire fluctualtions. Cheers MC otnmbrd wrote: About the only place I've seen "expansion joints", is on Navy ships (which is not to say some passenger ships might have them). On a tanker, the only place you'll see them will be on catwalks and in piping (G can get downright squeaky). Tankers, being built with longitudinal framing, tend to bend more, in that direction. otn DSK wrote: otnmbrd wrote: Doesn't really matter what size the boat is, you will get some degree of "flex", especially when you remove it from the water and put it on a hard stand. BG you want to see flex, you should watch and listen to a large tanker at sea, or watch one go from hog to sag when loading. Sure. Why else would they build expansion joints into the upper decks of big (or even medium-sized) ships? |
Hull Flexing
The navigator© wrote: I'd say It's BS because boats are simply not that rigid Oh yeah, and all boats are built to the same structural standard, aren't they. and it's hard to measure to an accuracy of 4 thou on big objects. Now that is total BS. It costs, but if you're willing to pay, I'll bring a crew and and gear, and show you how to measure movement in any axis on objects of any size & orientation down to 5 ten thousands +/- 1 It's part of what I do for a living, thanks very much. The NIST has occasionally asked me for advice on this type of thing. .... Even Ella has a backstay tension of 2,500 lbs when beating. Gee, and there's no difference between "2500#" and 15,000# is there? Why do I bother answering your posts? DSK |
Hull Flexing
"The Captain...cap n all" wrote:
How big was this thing Doug? It was a Frers designed 1-Tonner, maybe 38' or 39' LOA Most boats assume a slightly different shape in water as opposed to land only because they are suppored better. Sure, but then relatively few boats are built to be as rigid as high-end custom racers. At one point from the late 1970s through maybe the late 1980s it was fairly common to have a geodesic grid of aluminum struts inside, completely obstructing the cabin. What a PITA. I can't see anyone measuring 4 thou in a live environment and assuming accuracy to that level. Well, to be honest I don't know how the boatbuilder measured this. It's not a matter requiring scientific accuracy, but there are several ways you could measure it with an independent frame or taut wire. Nowadays you could set up a laser deflection meter easily and quickly. ....distortion measured on the newest IACC boats but the early 1990s boats had very high rig loads (10K kg and up) and very little (if any) distortion. They bent. Shucks, some of them broke! But I meant the hull deflection along major axis from the rig loads. I suspect that they bent very little (a couple millimeters or less), or that the hull deflection was designed in as a tuning feature.... "some chop coming up, let's get the boat a little more banana-shaped...." Some of the production boats I've sailed bend visibly, several inches, when the backstay is on and the rig loaded up. Fresh Breezes- Doug King |
Hull Flexing
How does that differ to her usual condition of standing by outside a harbour
with a fouled prop? CM "The_navigator©" wrote in message ... | I'd say It's BS because boats are simply not that rigid and it's hard to | measure to an accuracy of 4 thou on big objects. The flexability of most | boats is such that the side stays limit the spread of the hull as the | backstay is tightened (this is naval architecture 101). Current rig | tensions are much higher than they used to be. Even Ella has a backstay | tension of 2,500 lbs when beating. | | Cheers MC | | DSK wrote: | | The_navigator© wrote: | | 4 thou. measured on the back of a boat? Complete BS. | | | "The Captain...cap n all" wrote: | I would have thought so. | | | AFAIK there was no reason to BS about it, the boat was a one-off | and paid for. If I am interpreting the article about the boat | correctly, the distortion was measured at the mid length along a | straight from stem to center transom. | | If one is installing high powered hydraulics to control the rig, | it makes sense to make the hull & deck structure as rigid as | possible, within reasonable weight limits. I haven't seen any | figures for the distortion measured on the newest IACC boats but | the early 1990s boats had very high rig loads (10K kg and up) | and very little (if any) distortion. | | Fresh Breezes- Doug King | | | |
Hull Flexing
.... Even Ella has a backstay
tension of 2,500 lbs when beating. Gee, and there's no difference between "2500#" and 15,000# is there? Why do I bother answering your posts? DSK because you like the feeling of superiority? |
Hull Flexing
(to Navvie) Why do I bother answering your posts? Scott Vernon wrote: because you like the feeling of superiority? Yeah, but it's too easy. Kind of like clubbing baby seals... although in this case, the baby seal deserves every bit of it. DSK |
Hull Flexing
That boats are built differently has nothing to do with it. Sail boats are not rigid nor even near it. To be as rigid as you suggest would probably mean they would not float. If you had ever been in a real boat beating to windward your would know they are *not* rigid. Put your hand on the forstay and look at it unloading when she buries her bow and look at it going tight on the crest (that's revealed by the luff bending). It's loading up/unloading because the boat is flexing. If you ever get the chance (assuming that any boat owner could put up with your big mouth and BS) have a good hard look at the hull of a boat pounding hard to windward and look and feel hull panels flexing. The boat needs has to flex to reduce impact loadings because water is much less compressable than the boat. Once again you reveal your lack of experience with big boats by suggesting otherwise. This typifies your inability to grasp even simple ideas. As for measurent of a boat to 5 thou, look at the coefficent of expansion of say GRP or even Al (which expands muchg less) and then tell me how much a boat moves during a typical day/night temperature cycle. Now you want to tell me it's easy to measure a 5 thou deflection over a 40' boat? Even if the boat builder had access to interferometric equipment (which I'm sure they did not use -as there would be no point in such an accurate measurement) it would still be hard. If you think it's so easy how come you need a 'crew'. Lets face it this is yet more Doug Kig (I'm a ****ing hero) BS. Have'nt you ever wonder why you don't make more money -after all, you are such an expert... My point is that Ella is not a large racing boat and yet still has more than 1 ton rig tension. Cheers MC DSK wrote: The navigator© wrote: I'd say It's BS because boats are simply not that rigid Oh yeah, and all boats are built to the same structural standard, aren't they. and it's hard to measure to an accuracy of 4 thou on big objects. Now that is total BS. It costs, but if you're willing to pay, I'll bring a crew and and gear, and show you how to measure movement in any axis on objects of any size & orientation down to 5 ten thousands +/- 1 It's part of what I do for a living, thanks very much. The NIST has occasionally asked me for advice on this type of thing. .... Even Ella has a backstay tension of 2,500 lbs when beating. Gee, and there's no difference between "2500#" and 15,000# is there? Why do I bother answering your posts? DSK |
Hull Flexing
What's your point?
Cheers MC Capt. Mooron wrote: How does that differ to her usual condition of standing by outside a harbour with a fouled prop? CM "The_navigator©" wrote in message ... | I'd say It's BS because boats are simply not that rigid and it's hard to | measure to an accuracy of 4 thou on big objects. The flexability of most | boats is such that the side stays limit the spread of the hull as the | backstay is tightened (this is naval architecture 101). Current rig | tensions are much higher than they used to be. Even Ella has a backstay | tension of 2,500 lbs when beating. | | Cheers MC | | DSK wrote: | | The_navigator© wrote: | | 4 thou. measured on the back of a boat? Complete BS. | | | "The Captain...cap n all" wrote: | I would have thought so. | | | AFAIK there was no reason to BS about it, the boat was a one-off | and paid for. If I am interpreting the article about the boat | correctly, the distortion was measured at the mid length along a | straight from stem to center transom. | | If one is installing high powered hydraulics to control the rig, | it makes sense to make the hull & deck structure as rigid as | possible, within reasonable weight limits. I haven't seen any | figures for the distortion measured on the newest IACC boats but | the early 1990s boats had very high rig loads (10K kg and up) | and very little (if any) distortion. | | Fresh Breezes- Doug King | | | |
Hull Flexing
Common? Name 20 racing boats that "have a geodesic grid of aluminum
struts inside, completely obstructing the cabin". Can you even name one? You are such a BS artist. Cheers MC DSK wrote: At one point from the late 1970s through maybe the late 1980s it was fairly common to |
Hull Flexing
Oh about 32 degrees in a pinch... You?
CM "The_navigator©" wrote in message ... | What's your point? | | Cheers MC | | Capt. Mooron wrote: | | How does that differ to her usual condition of standing by outside a harbour | with a fouled prop? | | CM | | "The_navigator©" wrote in message | ... | | I'd say It's BS because boats are simply not that rigid and it's hard to | | measure to an accuracy of 4 thou on big objects. The flexability of most | | boats is such that the side stays limit the spread of the hull as the | | backstay is tightened (this is naval architecture 101). Current rig | | tensions are much higher than they used to be. Even Ella has a backstay | | tension of 2,500 lbs when beating. | | | | Cheers MC | | | | DSK wrote: | | | | The_navigator© wrote: | | | | 4 thou. measured on the back of a boat? Complete BS. | | | | | | "The Captain...cap n all" wrote: | | I would have thought so. | | | | | | AFAIK there was no reason to BS about it, the boat was a one-off | | and paid for. If I am interpreting the article about the boat | | correctly, the distortion was measured at the mid length along a | | straight from stem to center transom. | | | | If one is installing high powered hydraulics to control the rig, | | it makes sense to make the hull & deck structure as rigid as | | possible, within reasonable weight limits. I haven't seen any | | figures for the distortion measured on the newest IACC boats but | | the early 1990s boats had very high rig loads (10K kg and up) | | and very little (if any) distortion. | | | | Fresh Breezes- Doug King | | | | | | | | | |
Hull Flexing
The navigator© wrote:
Common? Name 20 racing boats that "have a geodesic grid of aluminum struts inside, completely obstructing the cabin". Can you even name one? Sure. Most of the top One Tonners and Half Tonners between about 1977 and 1985. That's not 20, but it's more than one. Jan and Meade Gougeon built two Canada's Cup racers with such strut grids. When I get home and consult my stack of old racing newsletters, I can post more names, designers, builders, and the competitive venues... if I deem it worth my time to continue making a fool of you... You are such a BS artist. Hardly. The problem here is that I state many truths which are outside your limited experience. DSK |
Hull Flexing
Not one of those boats "have a geodesic grid of aluminum
struts inside, completely obstructing the cabin". C'mon post the evidence! Cheers MC DSK wrote: The navigator© wrote: Common? Name 20 racing boats that Can you even name one? Sure. Most of the top One Tonners and Half Tonners between about 1977 and 1985. That's not 20, but it's more than one. Jan and Meade Gougeon built two Canada's Cup racers with such strut grids. When I get home and consult my stack of old racing newsletters, I can post more names, designers, builders, and the competitive venues... if I deem it worth my time to continue making a fool of you... You are such a BS artist. Hardly. The problem here is that I state many truths which are outside your limited experience. DSK |
Hull Flexing
Bwhahhahahahaha
In this discussion the only thing limited is my ability to tolerate your near constant BS. Cheers MC Hardly. The problem here is that I state many truths which are outside your limited experience. DSK |
Hull Flexing
?
Cheers MC Capt. Mooron wrote: Oh about 32 degrees in a pinch... You? CM "The_navigator©" wrote in message ... | What's your point? | | Cheers MC | | Capt. Mooron wrote: | | How does that differ to her usual condition of standing by outside a harbour | with a fouled prop? | | CM | | "The_navigator©" wrote in message | ... | | I'd say It's BS because boats are simply not that rigid and it's hard to | | measure to an accuracy of 4 thou on big objects. The flexability of most | | boats is such that the side stays limit the spread of the hull as the | | backstay is tightened (this is naval architecture 101). Current rig | | tensions are much higher than they used to be. Even Ella has a backstay | | tension of 2,500 lbs when beating. | | | | Cheers MC | | | | DSK wrote: | | | | The_navigator© wrote: | | | | 4 thou. measured on the back of a boat? Complete BS. | | | | | | "The Captain...cap n all" wrote: | | I would have thought so. | | | | | | AFAIK there was no reason to BS about it, the boat was a one-off | | and paid for. If I am interpreting the article about the boat | | correctly, the distortion was measured at the mid length along a | | straight from stem to center transom. | | | | If one is installing high powered hydraulics to control the rig, | | it makes sense to make the hull & deck structure as rigid as | | possible, within reasonable weight limits. I haven't seen any | | figures for the distortion measured on the newest IACC boats but | | the early 1990s boats had very high rig loads (10K kg and up) | | and very little (if any) distortion. | | | | Fresh Breezes- Doug King | | | | | | | | | |
Hull Flexing
Actually quite a few sailboats *are* much more rigid than you seem to
know. You're taking your experience on plastic boats and assuming it is generally applicable. The flex in a steel or ferrocement hull is certainly there (everything flexes to some degree), but it's a fraction of what is common in lightweight toy racing boats which are built to minimal standards of seaworthiness and do, indeed, flex. In fact, the toy boats often break when coming off a fairly moderate wave, as recent Sydney-Hobart races have shown so well. The remark about water being much less compressible than the boat is pure & utter bull****. Even frozen water is a lot more compressible than steel. Also has lower shear strength, tensile strength etc. As to measurement of a boat to 0.005", I can easily believe that this is possible. It's not even all that difficult. Whether there's any point and whether the measurement is repeatable are different issues. Peter Wiley In article , The_navigator© wrote: That boats are built differently has nothing to do with it. Sail boats are not rigid nor even near it. To be as rigid as you suggest would probably mean they would not float. If you had ever been in a real boat beating to windward your would know they are *not* rigid. Put your hand on the forstay and look at it unloading when she buries her bow and look at it going tight on the crest (that's revealed by the luff bending). It's loading up/unloading because the boat is flexing. If you ever get the chance (assuming that any boat owner could put up with your big mouth and BS) have a good hard look at the hull of a boat pounding hard to windward and look and feel hull panels flexing. The boat needs has to flex to reduce impact loadings because water is much less compressable than the boat. Once again you reveal your lack of experience with big boats by suggesting otherwise. This typifies your inability to grasp even simple ideas. As for measurent of a boat to 5 thou, look at the coefficent of expansion of say GRP or even Al (which expands muchg less) and then tell me how much a boat moves during a typical day/night temperature cycle. Now you want to tell me it's easy to measure a 5 thou deflection over a 40' boat? Even if the boat builder had access to interferometric equipment (which I'm sure they did not use -as there would be no point in such an accurate measurement) it would still be hard. If you think it's so easy how come you need a 'crew'. Lets face it this is yet more Doug Kig (I'm a ****ing hero) BS. Have'nt you ever wonder why you don't make more money -after all, you are such an expert... My point is that Ella is not a large racing boat and yet still has more than 1 ton rig tension. Cheers MC DSK wrote: The navigator© wrote: I'd say It's BS because boats are simply not that rigid Oh yeah, and all boats are built to the same structural standard, aren't they. and it's hard to measure to an accuracy of 4 thou on big objects. Now that is total BS. It costs, but if you're willing to pay, I'll bring a crew and and gear, and show you how to measure movement in any axis on objects of any size & orientation down to 5 ten thousands +/- 1 It's part of what I do for a living, thanks very much. The NIST has occasionally asked me for advice on this type of thing. .... Even Ella has a backstay tension of 2,500 lbs when beating. Gee, and there's no difference between "2500#" and 15,000# is there? Why do I bother answering your posts? DSK |
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