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A new class of dinghy?

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turnturtle View Drop Down
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Post Options Post Options   Quote turnturtle Quote  Post ReplyReply Direct Link To This Post Topic: A new class of dinghy?
    Posted: 22 Sep 18 at 8:50pm
I had a 9.5 VG5 - it was very dinghy like. Because it’s designed to be adjusted on the fly, have a tight leech for light winds and cover a very broad wind range. Most windsurfers have 5 sails to cover what any dinghy could do without even reefing, Nevermind shedding cloth with a smaller rag and carrying a van full of canvas.
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Old Timer View Drop Down
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Post Options Post Options   Quote Old Timer Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 18 at 8:34am
Originally posted by Chris 249

Originally posted by Old Timer

 
I know Frank was highly educated pilot & meteorologist; is Julian similarly educated?

I had great respect for Frank as a person, but I'm 99.9999% sure he didn't go to higher education, or if he started he certainly didn't finish it because of WW2. Sadly, I understand from someone who knew him better than I did that all his life, he felt that he had missed out badly because of his lack of higher formal education. Perhaps that's why although he had many great insights, he also had a tendency to bend evidence to fit the conclusion he desired.

Julian did a couple of years at uni. As Jim mentioned, his older brother Mark is a (very successful) engineer who actually designed the Tasar's underwater sections and is a major influence on Julian's approach. All very pleasant, well mannered and interesting people.

A lot of what is presented in the book is presented as science but I'm guessing it is really just a series on anecdotes ... useful ones ...

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RS400atC View Drop Down
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Post Options Post Options   Quote RS400atC Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 18 at 8:55am
Originally posted by Old Timer

...

A lot of what is presented in the book is presented as science but I'm guessing it is really just a series on anecdotes ... useful ones ...

[/QUOTE]
The Bethwaite books are very much from his point of view.
But his methodical approach to measuring e.g. hull drag is pretty much science.

What's lacking is anyone else writing from a different viewpoint with as much insight or experience.

I suppose that begs the questiom:
Who would we like to see writing about dinghy design?
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Gordon 1430 View Drop Down
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Post Options Post Options   Quote Gordon 1430 Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 18 at 9:48am
Hi Rs400
Phil Morrison, Ian Howlett, Punk/ Dzero designer whos name has gone straight out my head.
Kevin Elway, Paul Bieker and other int 14 / Moth designers
Gordon
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Post Options Post Options   Quote 423zero Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 18 at 10:00am
The War took more than lives, he could have had his imaginative side taken out of him though by a more formal education, whatever, he wouldn't have been the man he was.
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JimC View Drop Down
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Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 18 at 10:17am
I'm not aware of anyone else who has taken such a systematic approach to measuring dinghy performance. Even my limited contact with the RYA Olympic setup suggests to me that while they are extremely good at doing practical empirical two boat testing of the "setting A is quicker than setting b" variety its strictly limited to qualitative boat speed in Olympic classes and doesn't really involve much actual measurement. It fulfils their needs, so fair enough.

I've tried to enthuse people to do some proper performance measurement in some of the development classes I've been involved in, but no-one has ever caught the vision.

With the solitary exception of a nicely designed trial of mainsheet systems by the Topper class (which I was involved with and did the analysis afterwards, but wasn't involved in designing the trial) I'm not aware of anything else I'd really call an organised data gathering exercise.

I could wish the Bethwaites were a little more public with their data, but they've stated that they are happy to share data with anyone who has something to contribute in the opposite direction. Which, as far as I can see is no-one, but you can't blame them for that. And yes, I could wish that FB had shown his workings more rather than simply presenting his conclusions, but it still seems more than anyone else I have come across does.

The thing is this sort of systematic testing involves lots of tedious hard work. Frank was lucky that his family, especially I believe Julian and Nicola, were prepared to give up so much time to assist.

Edited by JimC - 24 Sep 18 at 11:22am
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Post Options Post Options   Quote jeffers Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 18 at 10:41am
Originally posted by Gordon 1430

Hi Rs400
Phil Morrison, Ian Howlett, Punk/ Dzero designer whos name has gone straight out my head.
Kevin Elway, Paul Bieker and other int 14 / Moth designers

Dan Holman is the designer you are looking for. Also penned the Fusion and his own I14 design (and hangs round here occasionally)...
Paul
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Post Options Post Options   Quote RS400atC Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 18 at 11:21am
Originally posted by Gordon 1430

Hi Rs400
Phil Morrison, Ian Howlett, Punk/ Dzero designer whos name has gone straight out my head.
Kevin Elway, Paul Bieker and other int 14 / Moth designers

I'd add Dr Joachim Happrecht, designer of the Musto Skiff.

But a good book that analysed the work of all/any of the above in terms I could understand would be on my xmas list.
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Post Options Post Options   Quote Old Timer Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 18 at 2:00pm
Originally posted by JimC

I'm not aware of anyone else who has taken such a systematic approach to measuring dinghy performance. Even my limited contact with the RYA Olympic setup suggests to me that while they are extremely good at doing practical empirical two boat testing of the "setting A is quicker than setting b" variety its strictly limited to qualitative boat speed in Olympic classes and doesn't really involve much actual measurement. It fulfils their needs, so fair enough.

I've tried to enthuse people to do some proper performance measurement in some of the development classes I've been involved in, but no-one has ever caught the vision.

With the solitary exception of a nicely designed trial of mainsheet systems by the Topper class (which I was involved with and did the analysis afterwards, but wasn't involved in designing the trial) I'm not aware of anything else I'd really call an organised data gathering exercise.

I could wish the Bethwaites were a little more public with their data, but they've stated that they are happy to share data with anyone who has something to contribute in the opposite direction. Which, as far as I can see is no-one, but you can't blame them for that. And yes, I could wish that FB had shown his workings more rather than simply presenting his conclusions, but it still seems more than anyone else I have come across does.

The thing is this sort of systematic testing involves lots of tedious hard work. Frank was lucky that his family, especially I believe Julian and Nicola, were prepared to give up so much time to assist.


The real problem is our sport involves such a huge number of variables that are difficult to control in order to perform any sort of systematic testing that would pass the approval of a "proper scientist" we are left with the task of drawing conclusions from a series of less than perfect experiments.

I think FB probably has done better than anyone else in his experiments so remains the leader in this respect. 

The real challenge is that no new dinghy designer could sensibly afford the R&D time to make a boat financially viable. If all FBs testing time had been built into the cost of launching the Tasar then the whole process would probably still be in debt ... time is money ...


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Daniel Holman View Drop Down
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Post Options Post Options   Quote Daniel Holman Quote  Post ReplyReply Direct Link To This Post Posted: 24 Sep 18 at 6:46pm
Fb was a prolific empiricist as is Jb. Not much of fb work on dinghy design would stand up to academic peer review, inherent bitchiness of that arena notwithstanding. A lot of very fanciful claims have come out of the camp over the years. That said it’s a big cache of empirical data that is pretty interesting and no doubt has a lot of merit, and would cost a tonne of money to replicate. Most of it pertains to maximising performance from given parameters which is more development class specific, and a fair bit of that came from an era where there was a fair bit of cash in developing 18s. That said the 29er and 49er are pretty nicely resolved production boats to my mind, evidence of working with other collaborators with a good industrial design sensibility.
If you want more classical texts go for marchaj aero hydrodynamics of sailing, there are Heaps of books and papers on resistance of sailing yacht forms, semi displacement forms and planing forms., for more practical tact design texts go for Larson/Elias son or claughton/wellicome/shenoi. With the proviso that dinghies bring their own set of softer ergonomic and “user experience” issues that can trip up thoroughbred yacht designers. Back in the day these things were discovered trough trial and error empiricism in development classes and to a smaller extent in developing production boats but less development class work goes on these days.
A really really good paper was written by Paul Bieker for the hpyd symposium in 2008 packed full of good info pertaining to design and engineering of small light boats. Its online somewhere just checked his site and that link is down. He has done good articles in old ie 2002 professional boatbuilder magazine. I did a test of 4 systematic variants of an i14 design vs a basis in 2014. We only had a day and whilst encouraging, raised as many questions as it answered. Always yearned for another day in the tank!
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