Steelboats

[rotrax]

Right, so we can make our own assumptions.

Absolutely, you are entitled to your opinions, and you don't need any specialist knowledge for them. I'm not getting at you at all.

In the interest of fairness, I do find it somewhat strange that a person says that he " would tend towards Gisborne, rather than BS", when/if he knows nothing at all about the former. I merely wondered if he was basing his judgement on anything stronger than blind prejudice.

Google Brent Swain and pretty soon, from - IIRC - Cruisers Forum you get a headline ' Shit Brent Swain Says'

Like sailing in 95 MPH winds.

Thats not sailing, from my modest experience thats survival conditions.

Plus many other instances.

There is no doubt that a steel boat using many of the exellent ideas Brent suggests for longevity and corrosion resistance would survive better than my Hartley 32 which does not have the advantages of Brents experience. There is no doubt that a steel boat is the most sensible for full time liveaboard cruising in out of the way places where self reliance and easy repair is paramount.

But while I and others will accept that, Brent will not accept that good strong GRP sailboats are made in the hundreds by manufacturers and give good safe service to their owners in doing the same job.

He also feels that marine professionals, chandlers and brokers are rip off merchants. While some may well be, I have not experienced their predations during my sailing career.

I think he is troubled and cant believe that the Gospel he preaches is not better recieved.

 

[Brent Swain]

If the crew of Gringo had listened to the advice of plastic evangelists ,instead of steel boat people, the boat would have been cut in half by that freighter and killed all of them. If Moitessier had been in a plastic boat instead of steel, the freighter he hit off S Africa would have sunk and killed him.
No John, you have it bass ackwards ,. It is your advice which is dangerous, not mine.
A Canadian was off the Great Barrier reef when his Yanmar mounts broke , and his loose engine punched a hole in his hull, something which couldn't happen with a steel hull. He barely got off , rescued by a helicopter. Later he went missing , enroute from Hawaii to BC. Caused by "Dangerous " advice to go plastic over steel? Probably .
If the Sleavin family had not gone with "dangerous " bad advice to choose plastic over steel, their boat would have had no more damage than the Gringo did, when hit by a freighter, and they would have probably all survived . "Dangerous" bad advice to go plastic killed all but one, proving how dangerous such advice can prove to be. No John, it is your advice which is dangerous, not mine.
On of my 36 footers pounded across 300 yards of Fijian coral reef , then was dragged back across it by a tug ,only a slight dent in the keel bottom. Later she hit a freighter in Gibraltar, no serious damage . No John , it would have been following your "dangerous" bad advice to go plastic, which could have killed him in both incidents, not my advice to go steel, nor my design, which proved very capable of surviving what would have broken up a plastic boat in minutes,
You say he should have been in the latter? For safety's sake? VERY BAD ADVICE!
My advice put him in steel .Proven, beyond all reasonable doubt, to have been very good advice!
Robin, a young lady I met in Auckland, set out for Fiji on a plastic boat she was crewing on. Got too close to a NZ beach and she broke up. Lost her life to myths about plastic being the best choice, your kind of bad, "dangerous" advice John, not mine.
Neither Callahan, nor Baileys, not he kid I met who had his boat sunk by a whale at night on the Baja , would have had their boats sunk under them, had thy been steel. Your kind of "Dangerous advice" John, not mine.
When Joshua went aground in Cabo, a stock plastic boat landed on top of her, and disintegrated. Joshua still sails, thanks to her owner not buying your kind of "Dangerous, bad advice ."
Had the South African boat which had a whale land on deck been plastic it would have broken in half, probably with loss of life. Only following the GOOD advice , to go steel, prevented that, the kind of advice I give. Following the "dangerous" bad advice to go plastic, would have probably killed someone, the kind of advice you give .
When Winston Bushnell hit submerged ice in the NW passage , at full speed, it stopped the boat dead in its tracks sending him flying into the companionway . No hull damage on his origami brentboat. Had she been plastic, they would have sunk on the spot , very quickly, much to far from any help, in arctic waters . Good advice to go origami steel, is the only reason they are still alive.
These cases are just the tip of the ice berg , of such incidents.

 

[john_morris_uk]

I think we’ve probably had enough of this dangerous delusional nonsense.

All of the examples that Brent is quoting are explained in this thread. I might be one if the volunteer moderators but I can explain that others behind the scenes are getting extremely anxious about the use of these pages to sell his designs and plans which may amount to the peddling of potentially dangerous designs.

Despite being given many opportunities to demonstrate and verify his fantastic claims for his designs, Brent merely launches into another tirade citing old worn out examples. Gross assumptions and guesses are made to justify his claims.

I’m not sure how long this thread will remain live. (As I’m a contributor to the thread, the unwritten rule of our moderation team is that it’s up to others to decide on any moderation. )

 

[rotrax]

Well, its obvious we are flogging the proverbial dead 'un trying to have a sensible debate with Brent, so feel free to close it.

It reinforces what a SA poster wrote regarding Brent - something like ' his forte is mind numbing repetition'

Well, he got that right!

 

[Brent Swain]

Google Brent Swain and pretty soon, from - IIRC - Cruisers Forum you get a headline ' Shit Brent Swain Says'

Like sailing in 95 MPH winds.
__________________________________________________________________________________________________________________________________________
No one ever said "sailing in 95 knots" only "encountering 95 knots!" Another "made up" straw man argument, deleting the credibility of the Steve who made it up, and the site which carries it.
______________________________________________________________________________________________________________________________________________________________________________

Thats not sailing, from my modest experience thats survival conditions.

Plus many other instances.
__________________________________________________________________________________________________________________________________________________
More such "made up" straw man arguments! Many taken totally out of context , heavily edited for maximum distortion.
____________________________________________________________________________________________________________________________________

There is no doubt that a steel boat using many of the exellent ideas Brent suggests for longevity and corrosion resistance would survive better than my Hartley 32 which does not have the advantages of Brents experience. There is no doubt that a steel boat is the most sensible for full time liveaboard cruising in out of the way places where self reliance and easy repair is paramount.

But while I and others will accept that, Brent will not accept that good strong GRP sailboats are made in the hundreds by manufacturers and give good safe service to their owners in doing the same job.
____________________________________________________________________________________________________________________________________________________________________
95 % of that job being sitting in marinas having cocktails drunk aboard them.Good safe service, no doubt, for that use.
___________________________________________________________________________________________________________________________________________

He also feels that marine professionals, chandlers and brokers are rip off merchants. While some may well be, I have not experienced their predations during my sailing career.
___________________________________________________________________________________________________________________________________________________________
Put the word Marine on it ,and double the price tag, is a very common complaint by many cruisers, on many sites.

I think he is troubled and cant believe that the Gospel he preaches is not better recieved.

-------------------------------------------------------------------------------------------------------------------------------------------------
I have had many people personally thank me for saving them tens of thousands of dollars. When they do it on line they get instantly banned, and accused of being me, especially on BD.net. Thier sponsors don't want people to know of better, cheaper, more reliable , alternatives to what they are selling. Snobs don't want low income people to be able to cruise.
I recently got an email from a guy who said his parents always dreamed of cruising, but were convinced they had to be rich to do that. He said that, had they had my advice , he could have grown up on a cruising boat cruising the world. Disinformation snobbery, cost them, and him the cruising dream.

 

[Brent Swain]

A chandler near here has Harken blocks rated at 900 lbs, for $40 each. The one in my book costs $2 ,and I recently broke a line with it rated at 3700 lbs breaking strength.Try it your self , make one up and compare them. And they say 900 lbs is safer than 3700 lbs? If the former has a brand name and a high enough price tag on it? Now that's dangerous advice.

 

[dom]

Self promotion at its most mendacious is Brent's trademark.

Dragging the memories of deceased or injured sailors into this delusional fantasy represents another low.

If the crew of Gringo had listened to the advice of plastic evangelists ,instead of steel boat people, the boat would have been cut in half by that freighter and killed all of them. If Moitessier had been in a plastic boat instead of steel, the freighter he hit off S Africa would have sunk and killed him.
No John, you have it bass ackwards ,. It is your advice which is dangerous, not mine.
A Canadian was off the Great Barrier reef when his Yanmar mounts broke , and his loose engine punched a hole in his hull, something which couldn't happen with a steel hull. He barely got off , rescued by a helicopter. Later he went missing , enroute from Hawaii to BC. Caused by "Dangerous " advice to go plastic over steel? Probably .
If the Sleavin family had not gone with "dangerous " bad advice to choose plastic over steel, their boat would have had no more damage than the Gringo did, when hit by a freighter, and they would have probably all survived . "Dangerous" bad advice to go plastic killed all but one, proving how dangerous such advice can prove to be. No John, it is your advice which is dangerous, not mine.
On of my 36 footers pounded across 300 yards of Fijian coral reef , then was dragged back across it by a tug ,only a slight dent in the keel bottom. Later she hit a freighter in Gibraltar, no serious damage . No John , it would have been following your "dangerous" bad advice to go plastic, which could have killed him in both incidents, not my advice to go steel, nor my design, which proved very capable of surviving what would have broken up a plastic boat in minutes,
You say he should have been in the latter? For safety's sake? VERY BAD ADVICE!
My advice put him in steel .Proven, beyond all reasonable doubt, to have been very good advice!
Robin, a young lady I met in Auckland, set out for Fiji on a plastic boat she was crewing on. Got too close to a NZ beach and she broke up. Lost her life to myths about plastic being the best choice, your kind of bad, "dangerous" advice John, not mine.
Neither Callahan, nor Baileys, not he kid I met who had his boat sunk by a whale at night on the Baja , would have had their boats sunk under them, had thy been steel. Your kind of "Dangerous advice" John, not mine.
When Joshua went aground in Cabo, a stock plastic boat landed on top of her, and disintegrated. Joshua still sails, thanks to her owner not buying your kind of "Dangerous, bad advice ."
Had the South African boat which had a whale land on deck been plastic it would have broken in half, probably with loss of life. Only following the GOOD advice , to go steel, prevented that, the kind of advice I give. Following the "dangerous" bad advice to go plastic, would have probably killed someone, the kind of advice you give .
When Winston Bushnell hit submerged ice in the NW passage , at full speed, it stopped the boat dead in its tracks sending him flying into the companionway . No hull damage on his origami brentboat. Had she been plastic, they would have sunk on the spot , very quickly, much to far from any help, in arctic waters . Good advice to go origami steel, is the only reason they are still alive.
These cases are just the tip of the ice berg , of such incidents.

 

[NotBirdseye]

Hey Brent, can you find links to independent verification/citations for your claims, preferably ones that we can check the qualifications of? For example, where has been 'proven beyond all reasonable doubt'? That's a surprisingly high bar. I'd also like a specialist (naval architect anywhere?) to confirm that the boat would have been cut in half if it hadn't been steel. At that size and momentum I don't think it really matters what material a yacht is made out of.

It's not that we don't trust your word it's... okay, we don't trust a word you're saying.

Especially since the last steel boat I know of that hit an ice berg at full speed sank, quite famously.

Also, whose bright idea was it to sail straight over a reef and then being dragged back across it before deciding to have an argument with a freighter... I really worry about some people. Maybe they shouldn't be on a boat at all!

 

[Gisborne]

Notice that Brent doesn't address factual criticism of his claims.

The sea is what boats should be designed for. Brent's design trying to get around the horn rolled three times. Brent lies wholesale about his boats stability and they have a reputation for being very tender and not standing up to sail. What does that say?

So far an honest estimate by The naval architect Tad Roberts is an AVS of 131 degrees and it needs validating with an inclining test. Brent is still lying about his designs stability and he has on this thread. Here's Tad Roberts view https://www.boatdesign.net/threads/swain-bs_36-stability-curve.37070/page-18#post-456845

Brent also doesn't realise that steel boats have been driven under and sunk by ships just as other boats have been broken up. These days fitting an AIS is good life insurance. Just remember class B can be turned off by ships in busy shipping lanes to reduce clutter.

Yacht Design School is run by an engineer called Tom Mcnaughton, he's in Brent's locale and knows him and his boats well. He's very critical of Brent.


Quote Tom MacNaughton
" Periodically someone will just decide that the transverse framing is "not necessary. They always come up with great sounding verbal rationalizations but have never actually done the math.
The amount of weight you can save by tailoring construction to save the absolute maximum in weight, including custom spacing the transverse frames and other transverse members is so minimal and the mathematics necessary to properly predict where you can reduce transverse framing is so complex that I am certain that no one advocating the elimination of transverse framing has actually done the math.

They are just building cheap, weaker boats.

One North American advocate [Brent Swain] has written a book which he told me "proved" his case, yet on buying his book I found there was no real structural analysis in it and the one piece of math in the book which applied to reducing framing was wrong.

There have been recent attempts to reinvent the construction method. Any reduction of the scantlings simply produce a boat less strong than the other methods. Naturally a rationale for this cannot be put in engineering terms. There it would evaporate.

The overall rigidity of the boat is largely dependent upon the framing. This leads into another argument. This one says that you can eliminate the framing by increasing the thickness of the shell plating. While this would, in theory, and viewed in isolation be true. It does not really work out because stiffness usually comes from thin deep frame members with high section modulus for their weight. Thickening a thin relatively heavy plate to provide the lost strength from removing the frames is very inefficient. The net result is that if you eliminate framing you about double the weight of the hull shell.

In an actual calculation comparing a normal hull framed both longitudinally and transversely with one that eliminated the framing the increase in weight of the metal structure of the vessel was 96%. Even disregarding the consequences for plate forming operations and welding operations of going to thicker plate, it should be easy to see that the large weight penalty is not acceptable because the performance of the boat will suffer terribly.
Do we really believe that these people are making the shell plating as thick as necessary to gain back the strength lost by eliminating the framing, given this weight penalty? I think it highly unlikely in view of their claim that they can reduce costs. Therefore should a metal boat be promoted as “frameless” you can essentially say that something is wrong.

A North American advocate [Brent Swain] has written a book which in one place compares the stiffness increase obtainable by using a thicker plate versus a thinner using an erroneous prediction of the relationship of thickness to stiffness. Presumably his entire system advocating reduced framing is justified by basing it on this erroneous calculation. There appears to be another interesting reason for this intense desire to justify reduced framing. We have noticed that all the structural members whose removal is advocated are the ones whose shapes are difficult to predict if you do not understand how to design the vessel with developed surfaces and produce patterns and plate expansions graphically such that every piece of the boat can be precut and can be set up and welded into a predictable shape.

Instead of this fully predictive system these boats seem to start out as scale hull plate patterns created by trial and error by cutting shapes and “folding” them until a shape is derived which looks good. Then the full sized patterns for the plates are scaled up for various sized vessels. However this trial and error system leaves no way to predict the shapes of transverse frames, watertight bulkheads, floor timbers that follow the shape of the hull and keel, etc. Interestingly enough it is these same members whose shape cannot be predicted using these methods that suddenly are declared “unnecessary”. At best this seems an exercise in self-delusion.
One final argument made for “reduced framing” is that if boats are composed of curved surfaces and that curved surfaces are stiffer and therefore don’t need framing. Let’s get real, even to figure the deflection on a simple curved beam of constant radius gets you into calculus. When you get into anything as complex as a boat hull with varying curvature in all directions, not to mention chines, deck edges, varying loads from ballast keels, large engines or rigs, the math pretty much goes off the charts. I just simply don’t believe that the folks I’ve seen advocating this as a reason to reduce framing have done these calculations.
Even with today’s computers and some pretty fancy and expensive software achieving any significant weight savings given the normal complexities of hull shape is quite unlikely even without considering some of the other factors which tend to make it difficult to save weight in real world hulls. Among these are the fact that without frames to stiffen the structures all the stress simply runs to stress concentration points where the hull may be reversing direction of curvature, be flat for hydrodynamic reasons, have some sort of chine or other corner around which the stress will not carry without some support.
Given all this the prediction of stress levels to sufficient accuracy in any given area to allow the reduction of scantlings on the basic of curvature becomes unrewarding and in practice is never done. My experience is that the people asserting that they can make such scantlings reductions, although speaking with great confidence and often with much disparagement of those who question them have not in fact done the analysis necessary to develop rational scantlings and are in fact just deciding to believe what they want to believe. One common characteristic of these promotions seems to be little or no space devoted to any real structural analysis of the relationships between methods. There seems to be a lot of space devoted to circular arguments saying that no proof is needed because only very stupid people living in the past could possibly not see the superiority of this new method. The evidence that these people are stupid is that they ask for the proof! These are “religious” arguments in that we are asked to “have faith” and those who doubt are castigated as lacking in the vision of the “true believer”. You will find us always on the side of “doubt” rather than faith.
We are always worried that we have made a mistake, have failed to see a possible failure mode, are using a model that is not as predictive as it might be possible to construct, etc. The “true believer” is unencumbered by doubt and therefore need never check for mistakes, worry about failure of imagination, etc.
We don’t buy into this and you shouldn’t either. In conclusion, do not be distracted from the lessons of real structural analysis by the promotional materials of these companies.

This is simply another repetition of the mistakes that builders have made over and over. I would suggest remembering an old principle of design: If structural analysis says a boat is strong enough it may be wrong, but if structural analysis says a boat isn’t strong enough it is probably correct."

End quote (Tom MacNaughton YDS)

 

[john_morris_uk]

Notice that Brent doesn't address factual criticism of his claims.

The sea is what boats should be designed for. Brent's design trying to get around the horn rolled three times. Brent lies wholesale about his boats stability and they have a reputation for being very tender and not standing up to sail. What does that say?

So far an honest estimate by The naval architect Tad Roberts is an AVS of 131 degrees and it needs validating with an inclining test. Brent is still lying about his designs stability and he has on this thread. Here's Tad Roberts view https://www.boatdesign.net/threads/swain-bs_36-stability-curve.37070/page-18#post-456845

Brent also doesn't realise that steel boats have been driven under and sunk by ships just as other boats have been broken up. These days fitting an AIS is good life insurance. Just remember class B can be turned off by ships in busy shipping lanes to reduce clutter.

Yacht Design School is run by an engineer called Tom Mcnaughton, he's in Brent's locale and knows him and his boats well. He's very critical of Brent.


Quote Tom MacNaughton
" Periodically someone will just decide that the transverse framing is "not necessary. They always come up with great sounding verbal rationalizations but have never actually done the math.
The amount of weight you can save by tailoring construction to save the absolute maximum in weight, including custom spacing the transverse frames and other transverse members is so minimal and the mathematics necessary to properly predict where you can reduce transverse framing is so complex that I am certain that no one advocating the elimination of transverse framing has actually done the math.

They are just building cheap, weaker boats.

One North American advocate [Brent Swain] has written a book which he told me "proved" his case, yet on buying his book I found there was no real structural analysis in it and the one piece of math in the book which applied to reducing framing was wrong.

There have been recent attempts to reinvent the construction method. Any reduction of the scantlings simply produce a boat less strong than the other methods. Naturally a rationale for this cannot be put in engineering terms. There it would evaporate.

The overall rigidity of the boat is largely dependent upon the framing. This leads into another argument. This one says that you can eliminate the framing by increasing the thickness of the shell plating. While this would, in theory, and viewed in isolation be true. It does not really work out because stiffness usually comes from thin deep frame members with high section modulus for their weight. Thickening a thin relatively heavy plate to provide the lost strength from removing the frames is very inefficient. The net result is that if you eliminate framing you about double the weight of the hull shell.

In an actual calculation comparing a normal hull framed both longitudinally and transversely with one that eliminated the framing the increase in weight of the metal structure of the vessel was 96%. Even disregarding the consequences for plate forming operations and welding operations of going to thicker plate, it should be easy to see that the large weight penalty is not acceptable because the performance of the boat will suffer terribly.
Do we really believe that these people are making the shell plating as thick as necessary to gain back the strength lost by eliminating the framing, given this weight penalty? I think it highly unlikely in view of their claim that they can reduce costs. Therefore should a metal boat be promoted as “frameless” you can essentially say that something is wrong.

A North American advocate [Brent Swain] has written a book which in one place compares the stiffness increase obtainable by using a thicker plate versus a thinner using an erroneous prediction of the relationship of thickness to stiffness. Presumably his entire system advocating reduced framing is justified by basing it on this erroneous calculation. There appears to be another interesting reason for this intense desire to justify reduced framing. We have noticed that all the structural members whose removal is advocated are the ones whose shapes are difficult to predict if you do not understand how to design the vessel with developed surfaces and produce patterns and plate expansions graphically such that every piece of the boat can be precut and can be set up and welded into a predictable shape.

Instead of this fully predictive system these boats seem to start out as scale hull plate patterns created by trial and error by cutting shapes and “folding” them until a shape is derived which looks good. Then the full sized patterns for the plates are scaled up for various sized vessels. However this trial and error system leaves no way to predict the shapes of transverse frames, watertight bulkheads, floor timbers that follow the shape of the hull and keel, etc. Interestingly enough it is these same members whose shape cannot be predicted using these methods that suddenly are declared “unnecessary”. At best this seems an exercise in self-delusion.
One final argument made for “reduced framing” is that if boats are composed of curved surfaces and that curved surfaces are stiffer and therefore don’t need framing. Let’s get real, even to figure the deflection on a simple curved beam of constant radius gets you into calculus. When you get into anything as complex as a boat hull with varying curvature in all directions, not to mention chines, deck edges, varying loads from ballast keels, large engines or rigs, the math pretty much goes off the charts. I just simply don’t believe that the folks I’ve seen advocating this as a reason to reduce framing have done these calculations.
Even with today’s computers and some pretty fancy and expensive software achieving any significant weight savings given the normal complexities of hull shape is quite unlikely even without considering some of the other factors which tend to make it difficult to save weight in real world hulls. Among these are the fact that without frames to stiffen the structures all the stress simply runs to stress concentration points where the hull may be reversing direction of curvature, be flat for hydrodynamic reasons, have some sort of chine or other corner around which the stress will not carry without some support.
Given all this the prediction of stress levels to sufficient accuracy in any given area to allow the reduction of scantlings on the basic of curvature becomes unrewarding and in practice is never done. My experience is that the people asserting that they can make such scantlings reductions, although speaking with great confidence and often with much disparagement of those who question them have not in fact done the analysis necessary to develop rational scantlings and are in fact just deciding to believe what they want to believe. One common characteristic of these promotions seems to be little or no space devoted to any real structural analysis of the relationships between methods. There seems to be a lot of space devoted to circular arguments saying that no proof is needed because only very stupid people living in the past could possibly not see the superiority of this new method. The evidence that these people are stupid is that they ask for the proof! These are “religious” arguments in that we are asked to “have faith” and those who doubt are castigated as lacking in the vision of the “true believer”. You will find us always on the side of “doubt” rather than faith.
We are always worried that we have made a mistake, have failed to see a possible failure mode, are using a model that is not as predictive as it might be possible to construct, etc. The “true believer” is unencumbered by doubt and therefore need never check for mistakes, worry about failure of imagination, etc.
We don’t buy into this and you shouldn’t either. In conclusion, do not be distracted from the lessons of real structural analysis by the promotional materials of these companies.

This is simply another repetition of the mistakes that builders have made over and over. I would suggest remembering an old principle of design: If structural analysis says a boat is strong enough it may be wrong, but if structural analysis says a boat isn’t strong enough it is probably correct."

End quote (Tom MacNaughton YDS)

I predict that Brent will claim that Tom is a biased old school engineer and boat designer who doesn't know what he is talking about. He may even say that he is part of the conspiracy to stop people building cheap boats and getting off grid and enjoying themselves living a life that is only reserved for the wealthy.

Read the article and then read Brent's rants and decide who you trust. Tom seems to have rounded the thread off rather nicely. If people want to keep it open, then I will try and persuade my fellow mods to take no action, but don't hold your breath. My personal opinion is we need to be very careful about giving the oxygen of publicity to dangerous fools who try and sell their wares. To use an analogy, snake oil salesmen were banned from the medical world a long time ago.

 

[NotBirdseye]

In the interests of fairness...

I can't confirm Tom MacNaughton ever said nor published such a thing. All I can find are a few forum nobodies that said, "This person said..." Furthermore there's no evidence that Tom MacNaughton has any more qualifications than Brent.

https://www.boatdesign.net/threads/yacht-design-school.34047/

I would argue that Brent would be right to say Tom doesn't know what he's talking about.

Tad Roberts on the other hand does appear to know more or less what he's talking about judging from experience of actually building boats and working for other people particularly apprenticing on design and so on, they've also been published in a number of magazines. I'd like to verify their 'heritage' so to speak, but I'm much happier with the evidence there than I am with Brent's or Tom's.

 

[john_morris_uk]

In the interests of fairness...

I can't confirm Tom MacNaughton ever said nor published such a thing. All I can find are a few forum nobodies that said, "This person said..." Furthermore there's no evidence that Tom MacNaughton has any more qualifications than Brent.

https://www.boatdesign.net/threads/yacht-design-school.34047/

I would argue that Brent would be right to say Tom doesn't know what he's talking about.

Tad Roberts on the other hand does appear to know more or less what he's talking about judging from experience of actually building boats and working for other people particularly apprenticing on design and so on, they've also been published in a number of magazines. I'd like to verify their 'heritage' so to speak, but I'm much happier with the evidence there than I am with Brent's or Tom's.

That's an interesting assertion about Tom.

Tom actually studied Yacht Design according to this article. He was one of the first students at the Yacht Design Institute and was a hard working student. http://www.macnaughtongroup.com/tom.htm

One of Brent's most common complaints is that professional yacht designers have no experience of actually living and sailing aboard yachts. Here's a quote from the above article...

Tom's earliest design work concentrated on offshore liveaboard sailing yachts for the very natural reason that he and his family lived aboard and cruised full time. These types still provide a major part of the customer base today. Nevertheless he has designed many well loved small cruising powerboat designs, coastal cruising sail boats and moderate sized commercial craft up to 134 feet as well.

Brent might say that Tom doesn't know what he is talking about, but the evidence says otherwise.

 

[NotBirdseye]

Tom MacNaughton says Tom MacNaughton studied design. There's no third party references there. I'd point out that YDI (integrated with Westlawn) doesn't actually provide degrees and certainly nothing that could be used as far as employment goes. No doubt a worthwhile hobby for the curiously minded. There's no mention of Tom nor Edward Brewer on the Brooklin Boatyard website. In fact they state that design was done by themselves. I'm not saying that Tom isn't a talented designer, I'm saying his credentials don't stack up and could easily be called into question, which Brent would be well within his rights to do so.

Challenge Brent all you wish, but don't hold up someone who is on paper no better than Brent and expect to win any arguments.

 

[Brent Swain]

Yes , I'd much rather discuss and pass on what I have learned in over 40 years of steel boat building, designing , cruising and living aboard experience.
Sadly that gets constantly sabotaged by people quoting lies, or making up lies and disinformation, about my boats and steel boats in general, which simply cant be left unchallenged.
Some are only here to sabotage , taunt and jeer. Without, them we could have a great exchanged of info . This is the case with most steel boat discussions.
A few sites , such as facebook, and the origamiboat site , don't have this problem and have a large number of people with hands on, steel boat experience,
unlike those taken over by plastic evangelists, determined to block any exchange of steel boat info.
Anyone who wants info on any design , can go to those sites and ask people with actual hands on experience about any design, including asking their questions about my boats,
on the origamiboats site, yahoo groups, instead of relying on made up on the spot lies , by people who have never seen, let alone sailed on any of the boats they are making up lies about.

 

[Brent Swain]

That's an interesting assertion about Tom.

Tom actually studied Yacht Design according to this article. He was one of the first students at the Yacht Design Institute and was a hard working student. http://www.macnaughtongroup.com/tom.htm

One of Brent's most common complaints is that professional yacht designers have no experience of actually living and sailing aboard yachts. Here's a quote from the above article...



Brent might say that Tom doesn't know what he is talking about, but the evidence says otherwise.

Tom did a great job of providing steel boat designs, when few did, especially for low income, back yard builders. He made the most of the technology of his time. He circumnavigated on one of his Gazelles, or so I understand . Far more hands on experience , including building many with his own hands, than McNaughton or Perry can ever claim.
That doesn't mean they are perfect and cant be improved on, as I have done, by putting a wheelhouse on the midship deck on a couple of them, making a crawl space useful.
His comments about the need for transverse frames to increase longitudinal stiffness, would be just as ludicrous, regardless of who they came from .

 

[Gisborne]

Yes , I'd much rather discuss and pass on what I have learned in over 40 years of steel boat building, designing , cruising and living aboard experience.
Sadly that gets constantly sabotaged by people quoting lies, or making up lies and disinformation, about my boats and steel boats in general, which simply cant be left unchallenged.
Some are only here to sabotage , taunt and jeer. Without, them we could have a great exchanged of info . This is the case with most steel boat discussions.
A few sites , such as facebook, and the origamiboat site , don't have this problem and have a large number of people with hands on, steel boat experience,
unlike those taken over by plastic evangelists, determined to block any exchange of steel boat info.
Anyone who wants info on any design , can go to those sites and ask people with actual hands on experience about any design, including asking their questions about my boats,
on the origamiboats site, yahoo groups, instead of relying on made up on the spot lies , by people who have never seen, let alone sailed on any of the boats they are making up lies about.

So lets talk about stability. It's a good illustration of both your moral character since you knowingly lie about a significant safety issue. It illustrates your ignorance of the process of yacht design. I'll draw from the exchanges on Boatdesign net for this example where you clearly have no concept how stability is derived and how it's verified on a real boat.

And why don't you follow up Tad Roberts free offer of verifying the study he did for you by arranging a boat for him to test. The initial study that indicates that your boats have an AVS of no better than 131 degrees which is poor for a boat promoted as a rugged offshore design.

 

[Brent Swain]

I predict that Brent will claim that Tom is a biased old school engineer and boat designer who doesn't know what he is talking about. He may even say that he is part of the conspiracy to stop people building cheap boats and getting off grid and enjoying themselves living a life that is only reserved for the wealthy.

Read the article and then read Brent's rants and decide who you trust. Tom seems to have rounded the thread off rather nicely. If people want to keep it open, then I will try and persuade my fellow mods to take no action, but don't hold your breath. My personal opinion is we need to be very careful about giving the oxygen of publicity to dangerous fools who try and sell their wares. To use an analogy, snake oil salesmen were banned from the medical world a long time ago.

So do be more specific John, and tell us EXACTLY what you consider dangerous about a design which has cruised for many decades, over 350,000 miles of ocean cruising,from Cape Horn to the NW passage with no serious structural problems including severe groundings in big surf for up to weeks at a time.
Or, are you like the Mike Johns character on BD.net , who claimed ,that which has not broken in that many miles of ocean cruising, over decades ,just might break in the first 4 hours?

Or are you suggesting that no one with experience should be allowed to correct lies about a particular design, if he happens to be the designer?
Are you thus suggesting liars should have the last word?
Boy, that's one way to make a site real useful!

 

[Gisborne]

In the interests of fairness...

I can't confirm Tom MacNaughton ever said nor published such a thing. All I can find are a few forum nobodies that said, "This person said..." Furthermore there's no evidence that Tom MacNaughton has any more qualifications than Brent. .................

You can contact him yourself if you want to verify his authorship, Brent's aware than McNaughton wrote that.
But anyway, read the content, and regardless of the author it's well written and presents a good understanding of the processes and rationale of the Swain design methodology.

 

[Brent Swain]

Notice that Brent doesn't address factual criticism of his claims.

The sea is what boats should be designed for. Brent's design trying to get around the horn rolled three times. Brent lies wholesale about his boats stability and they have a reputation for being very tender and not standing up to sail. What does that say?

So far an honest estimate by The naval architect Tad Roberts is an AVS of 131 degrees and it needs validating with an inclining test. Brent is still lying about his designs stability and he has on this thread. Here's Tad Roberts view https://www.boatdesign.net/threads/swain-bs_36-stability-curve.37070/page-18#post-456845

Brent also doesn't realise that steel boats have been driven under and sunk by ships just as other boats have been broken up. These days fitting an AIS is good life insurance. Just remember class B can be turned off by ships in busy shipping lanes to reduce clutter.

Yacht Design School is run by an engineer called Tom Mcnaughton, he's in Brent's locale and knows him and his boats well. He's very critical of Brent.


Quote Tom MacNaughton
" Periodically someone will just decide that the transverse framing is "not necessary. They always come up with great sounding verbal rationalizations but have never actually done the math.
The amount of weight you can save by tailoring construction to save the absolute maximum in weight, including custom spacing the transverse frames and other transverse members is so minimal and the mathematics necessary to properly predict where you can reduce transverse framing is so complex that I am certain that no one advocating the elimination of transverse framing has actually done the math.

They are just building cheap, weaker boats.

One North American advocate [Brent Swain] has written a book which he told me "proved" his case, yet on buying his book I found there was no real structural analysis in it and the one piece of math in the book which applied to reducing framing was wrong.

There have been recent attempts to reinvent the construction method. Any reduction of the scantlings simply produce a boat less strong than the other methods. Naturally a rationale for this cannot be put in engineering terms. There it would evaporate.

The overall rigidity of the boat is largely dependent upon the framing. This leads into another argument. This one says that you can eliminate the framing by increasing the thickness of the shell plating. While this would, in theory, and viewed in isolation be true. It does not really work out because stiffness usually comes from thin deep frame members with high section modulus for their weight. Thickening a thin relatively heavy plate to provide the lost strength from removing the frames is very inefficient. The net result is that if you eliminate framing you about double the weight of the hull shell.

In an actual calculation comparing a normal hull framed both longitudinally and transversely with one that eliminated the framing the increase in weight of the metal structure of the vessel was 96%. Even disregarding the consequences for plate forming operations and welding operations of going to thicker plate, it should be easy to see that the large weight penalty is not acceptable because the performance of the boat will suffer terribly.
Do we really believe that these people are making the shell plating as thick as necessary to gain back the strength lost by eliminating the framing, given this weight penalty? I think it highly unlikely in view of their claim that they can reduce costs. Therefore should a metal boat be promoted as “frameless” you can essentially say that something is wrong.

A North American advocate [Brent Swain] has written a book which in one place compares the stiffness increase obtainable by using a thicker plate versus a thinner using an erroneous prediction of the relationship of thickness to stiffness. Presumably his entire system advocating reduced framing is justified by basing it on this erroneous calculation. There appears to be another interesting reason for this intense desire to justify reduced framing. We have noticed that all the structural members whose removal is advocated are the ones whose shapes are difficult to predict if you do not understand how to design the vessel with developed surfaces and produce patterns and plate expansions graphically such that every piece of the boat can be precut and can be set up and welded into a predictable shape.

Instead of this fully predictive system these boats seem to start out as scale hull plate patterns created by trial and error by cutting shapes and “folding” them until a shape is derived which looks good. Then the full sized patterns for the plates are scaled up for various sized vessels. However this trial and error system leaves no way to predict the shapes of transverse frames, watertight bulkheads, floor timbers that follow the shape of the hull and keel, etc. Interestingly enough it is these same members whose shape cannot be predicted using these methods that suddenly are declared “unnecessary”. At best this seems an exercise in self-delusion.
One final argument made for “reduced framing” is that if boats are composed of curved surfaces and that curved surfaces are stiffer and therefore don’t need framing. Let’s get real, even to figure the deflection on a simple curved beam of constant radius gets you into calculus. When you get into anything as complex as a boat hull with varying curvature in all directions, not to mention chines, deck edges, varying loads from ballast keels, large engines or rigs, the math pretty much goes off the charts. I just simply don’t believe that the folks I’ve seen advocating this as a reason to reduce framing have done these calculations.
Even with today’s computers and some pretty fancy and expensive software achieving any significant weight savings given the normal complexities of hull shape is quite unlikely even without considering some of the other factors which tend to make it difficult to save weight in real world hulls. Among these are the fact that without frames to stiffen the structures all the stress simply runs to stress concentration points where the hull may be reversing direction of curvature, be flat for hydrodynamic reasons, have some sort of chine or other corner around which the stress will not carry without some support.
Given all this the prediction of stress levels to sufficient accuracy in any given area to allow the reduction of scantlings on the basic of curvature becomes unrewarding and in practice is never done. My experience is that the people asserting that they can make such scantlings reductions, although speaking with great confidence and often with much disparagement of those who question them have not in fact done the analysis necessary to develop rational scantlings and are in fact just deciding to believe what they want to believe. One common characteristic of these promotions seems to be little or no space devoted to any real structural analysis of the relationships between methods. There seems to be a lot of space devoted to circular arguments saying that no proof is needed because only very stupid people living in the past could possibly not see the superiority of this new method. The evidence that these people are stupid is that they ask for the proof! These are “religious” arguments in that we are asked to “have faith” and those who doubt are castigated as lacking in the vision of the “true believer”. You will find us always on the side of “doubt” rather than faith.
We are always worried that we have made a mistake, have failed to see a possible failure mode, are using a model that is not as predictive as it might be possible to construct, etc. The “true believer” is unencumbered by doubt and therefore need never check for mistakes, worry about failure of imagination, etc.
We don’t buy into this and you shouldn’t either. In conclusion, do not be distracted from the lessons of real structural analysis by the promotional materials of these companies.

This is simply another repetition of the mistakes that builders have made over and over. I would suggest remembering an old principle of design: If structural analysis says a boat is strong enough it may be wrong, but if structural analysis says a boat isn’t strong enough it is probably correct."

End quote (Tom MacNaughton YDS)

Dead wrong , from the outset., I start with a set of hull lines, with all calculations done in the usual way. Then I make a model, to test the accuracy of the calculations . Plate shapes are taken off the model, or can be done with a computer.
Stiffness comes from shape ,not just hull thickness. This is the difference between a Roman arch, and a pile of stones stacked longitudinally , a huge factor, which McNaughton seems incapable of comprehending.
Like some of the rules quoted, he has no ability to comprehend the effect of complex shape on stiffness, something one has to take advantage of when working with a heavy material on small boats.
He has been proven dead wrong, with every ocean crossed, every severe grounding or impact survived, with minimal damage, if any. Like Mike Johns ,he claims, that which has had none of the problems he predicts, in decades of cruising ,over hundreds of thousands of miles ,just might happen in the first 4 hours.
He lives in a world of fantasy, no connection to reality.

 

[Brent Swain]

Tads proposed test is for initial stability, nothing do with ultimate stability. Step on the rail, and measure how many inches it heels, compared to similar boats. 2 inches for my 36.
That is initial stability . One of my 36 footers was in Tads back yard, Degnen Bay, the whole time that debate went on.
More beam gives you more initial stability, at the cost of ultimate stability as does lower free board. They are in many ways, opposites.
The buoyancy in my wheelhouse 3500 lbs is the equivalent of adding that much more balast