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May 1997 - Communications to AYRS

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Letters to AYRS

Design Competition

From: Dick Newick (AYRS Vice-President) Kittery Pt., Maine 03905, USA

Yes, AYRS should have a Europe 1 STAR design contest open for all vessels under 40ft long.

Instead of specifying self-righting, unsinkability, etc., the rules might say that judges will consider those items as well as cost and the probability of winning in class. Since safety is required by the race rules - and to win - it need not be mentioned. RWYC rules for the next race will not be published for some months, so 1996 race rules can be used for the contest with the proviso that a contestant can suggest a new rule if he can make a very strong case for it. I am thinking of the present prohibition of proas.

Prize: Publicity for the winning designs plus lifetime AYRS memberships for the first three places? If cash prize donors can be found that would be a good addition. Ask the Observer and Europe 1 ?

Cheers

Dick Newick

Design Competition

From: John Perry, (AYRS Committee), Shenley, Hertfordshire, UK

I have written to Dick Newick to invite him to help with judging, unless he wants to send in an entry.

I note the point made in the 1966 AYRS Design Competition rules that model boats should be sailed in scale winds which are lighter than the corresponding winds for full size boats. Despite this, I stand by my comment that a model race will be likely to be won by a boat which would be impractical at full size. The reason is not just a matter of windspeed, but more obviously that there are numerous design features which suit models but which would be impractical at full size. Just to take one of the very many possible examples, an efficient model is likely to have a sail semi permanently attached to the mast which would probably not work well for a full size ocean racing yacht, although I suppose we should not be too dogmatic about such matters. A model which would be practical at full size would probably need some methods of furling the sails and unless the model were made by an extremely skilled model maker this is likely to hamper the performance of the model. Another point which may in practice be of lesser importance, is that scaling the windspeed and dimensions reduces the Reynolds Number by something between one and two orders of magnitude.

I agree that a model boat race could be fun, we need to see how many of the potential competitors would be prepared to build models. I don't think we should put off competitors who do not have model building skill.

It would be nice to award the prize(s) in early-98, but realistically this may be too soon. We need to allow long enough for the designs to mature, especially if models are made, then a couple of months for judging. Late-97 is a bit early, but if we leave it too long people may lose interest.

International Workshop on Wind Energy

Forwarded to AYRS by John Reed, WSSRC

An International Workshop on Wind Energy & Landscape is being organised by the University of Genoa, Instituto di Scienza delle Costruzioni. It will be a world event with 300 papers already collected. The workshop, together with the "2nd European & African Conference on Wind Engineering" will take place in Genoa, Italy, June 22nd - 27th). More than 400 delegates are expected to attend.

The organisers would like to dedicate a special section to the issue of "Wind and Sea". They have asked for the co-operation of the Italian Yacht Club. The basic idea is to invite Organisations/Companies able to take there what is most advanced in speed sailing (conventional/non-conventional boats, sails, rigging, etc). The IYC is making available the facilities needed ashore and at sea in its port (Porticciolo Duca degli Abruzzi), and the Clubhouse for meetings etc.

Those interested should contact Gianni Migliorino at the YCI, telephone: +39 10 5365 363 or 365 fax: 380, or the conference secretary (Ms A Rizzo) by emailto:wel@scostr.unige.it.

Twisting Moments on Masts

From: David Bocquet, email: me3093@bristol.ac.uk

I am involved in a catamaran based design project at Bristol University, but have little experience of sailing or the 'feel' of how yachts will behave. I would like some subjective views as to how a 36ft by 19ft catamaran (hull separation 14ft) would behave if a twisting moment of up to 4000Nm was applied around its mast. The force is oscillatory with a period of around 5-10 seconds and varies from clockwise 4000NM to anticlockwise 4000NM. Primarily I'd like some indication of how the cat would yaw during each cycle. I imagine some kind of sinusoidal motion, perhaps slightly out of phase with the driving force, but of what magnitude? It's an odd question, I know, but I can't solve it analytically so AYRS is my only hope!!!

If it's any use the hull is a Heavenly Twin 36'.

Land/Sand Yachts - Information Wanted

We have received a request for information on land/sand yachts from Dr Angelo LIMA of Brazil. He saw a BBC film on a group of such craft crossing the Sahara desert some years ago, and was much impressed. In his area there are many long sandy beaches and steady trade winds . . . He suggests though that "high-flotation" (balloon?) tyres would be needed (presumably to cope with soft sand).

He is particularly looking for construction information and plans, and also for video footage.

Unfortunately all we have in an Internet address, <angelo.lima@sic.bbs.com.br>, however any material that cannot be sent in that way can be sent to him through AYRS and we will discover a postal address.

Afterword

from Alistair Stewart, 12 Hoveden Road, London

He can provide overnight accommodation for anyone travelling up to London for AYRS meetings, or the Boat Show etc.

He would like some help to sail his cruiser, including taking it round to Portland for Speed Week in the autumn.

An asymmetric foil on a swing keel could be another answer to maximising efficiency.

Reprint of "Canoes of Oceania" by Haddon & Hornell

Dennis Davis has told us of the possibility of a softback reprint of Haddon and Hornell's 'Canoes of Oceania' - the classic work on Pacific canoes, originally published in the 1930s by the Bishop Museum Press, Honolulu.

Apparently this may be republished in paperback format at around £35 to £40, if there is enough interest. This is very exciting, much cheaper than a second hand copy of the original, even if you can find one.

If anyone is interested they can reply to Dennis Davis, 9 Great Burrow Rise, Northam, BIDEFORD, Devon, EX39 1TB, England Tel: +44 (1237) 475 165

Please only reply if you are seriously interested, as someone will be making an investment decision based on these expressions of interest.

PS: Dennis is also publishing a new book, 'Build your own canoe', which contains full instructions for building his DD23 'Bliss' canoe, 13'7". This is available from Dennis at £14.99 plus £2.00 p&p. We have not yet seen the book, so cannot comment upon it, but Dennis is 'one of the good guys'. He produced the short-lived but very good "Afloat!" magazine.

TK


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