MERLIN ROCKET FORUM

Topic : Merlin design development stuff

Hello!
I have an essay to do on the history, design and development of a marine craft and have decided to do it on MR's (mostly because i love them sooooooo much!). I can prob blag most of it but if anyone knows anything useful about the details of design development, like why dif hull shapes where built and what the thinking was behind them i would love to know. Not to worry if not tho, i can prob scrape enough stuff together from what i know already, details would just be useful!
I've stuck my email up for contacts so...
Anyhoo hope everyone is well and looking forward to xmas!
Cheers for any help.
Ellie


Posted: 05/12/2006 19:07:05
By: Ellie
You might find a lot on this site , see link

http://www.merlinrocket.co.uk/design%20guide/cover%20page.html

Posted: 05/12/2006 20:46:40
By: Alan F
Funnily enough I did exactly the same thing for one of my first year projects at Southampton Uni, and found the design guide as per Alan F's comments plus also the much famed Merlin Rocket book by Mssrs Park & Holt most useful. I think I ended up with a fully battened, smooth skined and asymmetic kited beast and this was before the RS400 came along .......

Time for another revolution ....... ?

The rig could do with a simplification along the lines of the 18 foot skiffs some years ago, where they got rid of all the complicated rig adjustments and let the mast do its thing automatically. At least this ensures that the crew can look outside the boat for its speed (windshifts and the like) rather than looking into the boat. It would also save a few quid on fittings for a new boat!

Other recommended read is Frank Bethwaite's "bible" - High Performance Sailing - nothing to do with Merlins, but a fascinating read anyway, if you can get through the stuff on windsifts without falling asleep.

Enjoy.


Posted: 05/12/2006 21:24:35
By: Andy Hay
The Dinghy Year Book 1958 has a really good article on the development of Merlin hull shapes from the original Merlin through Rockets to Holt, Proctor, Adur and Rigden designs in the 1950's - with some line drawings.  It was written by Ian Proctor so it might be a bit biased but it does explain how his different designes evolved.


Posted: 05/12/2006 22:04:10
By: John Cooper
Ellie, I found reading Frank Bethwaite's book even harder than my engineering degree at Southampton...be warned!


Posted: 06/12/2006 09:04:25
By: Mags
I have got a copy of the Merlin Rocket book, but these are valuable items that seem to trade for a small fortune on e-vil-bay also if you really want to get technical a large book by a mr Marchaj with all sorts of formulae in as well as some of the Ian Proctor books on dinghy racing which has a fair bit on the early years of the Merlin.  You are welcome to a loan of some or all if helpful for your project

Andrew


Posted: 06/12/2006 10:45:17
By: Andrew M
Ellie,
I've just done an article for Dinghy Sailing Mag that focuses on how the development of Merlin hulls was influenced by the new rig technology. The article isn't out until the first week of Jan but if you'd like a copy of the text I'm happy to send that over.
Are you at Southampton (Solent?) Uni???? Some of my material will be used in a lecture that is coming up there in Jan. on the balance between hulls and rigs in all classes. Having looked at some of the work being done there it looks as if it will be a 'demanding' audience!
David


Posted: 06/12/2006 11:55:12
By: davidh
David - any chance of a copy too? I am playing with fitting a Tasar rotating ali mast on my boat in the spring, as I have finally worked through Frank's rig section in his bible. I know this has been done with large (stiff) section masts, but the Tasar rig is fundamentally different. I'll also simplify the controls as I am convinced that there has to be a better way forward. Regretably this is something else that the Aussies are better than us at .....

Got to work out how to stiffen the mast sufficiently to take the spinnaker loads over Christmas holidays ..... (!)


Posted: 06/12/2006 12:35:39
By: Andy Hay
Try the library for the Merlin Rocket book. If they don't have a copy they may be able to get Swindon's copy on inter-library loan.


Posted: 06/12/2006 12:44:24
By: Pat2121
Didnt Chris (cant rem which one) write his dissertation on the MR class?


Posted: 06/12/2006 12:56:07
By: Mags
Andy,

If you're into upper diamonds, lower Diamonds, jumper struts AND middle diamonds I might just have the picture for you!!
The piece is mainly historical but I'll try to get it into a format that can be mailed across complete with some of the pics.

Pat! Beware! MR, 6, 36 1066 and...... ? all have a place in this. So be careful, when I said at Shearwater that I wanted a picture of your bottom there was indeed method in the madness!

[email protected]

Posted: 06/12/2006 12:57:05
By: davidh
Andy , Did you know that Rein Zivold experimented with putting a spinnaker onto the Tasar , I believe he found the top mast too soft. Early Tasar top masts bent very easily and were retrospectively fitted with stiffners.The Tasar that I recently sold to your Dad had an unstiffened top mast so beware! I belive that the Aussies are experimeting ( informaly) with carbon topmasts with extra controlled flex to match the new mylar sails.Second Hand Tasar masts are rare as hens teeth and very expensive to replace!!


Posted: 06/12/2006 13:34:05
By: Rod Porteous
Ellie, you should speak to my Dad he has loads of old plans and could form a living history project.


Posted: 06/12/2006 13:47:26
By: Matthew Winder
I did a similar thing many moons ago and picked the brains of N12 designer Mal McDougal, who designed a 16 foot skiff, which was the basis of my project.  Your best port of call would be the designers and builders. They would have perfect nuggets of information, lines  drawings, pictures from which to make comparisons.  Why not try Winders, Kevin Driver, Linton or if you can get hold of him - Phil Morrison. Take a notebook and buy 'em a beer! Good luck!


Posted: 06/12/2006 13:50:13
By: mad jack
Yeah, thanks Allen, I have already had a quick noesy at that, it is handy! 
Is there any way i can get a hold of the 1958 article as its the older designs im going to struggle to get details on!
Cheers everyone for the help!
Ellie


Posted: 06/12/2006 18:55:06
By: Ellie
Ellie - I  have sent you an email about the "58 article.


Posted: 06/12/2006 19:19:05
By: John Cooper
There is a paper in one of the Cheasapeake symposia by Bob Ames on 14 design, although this is not contemporary it is quite analytical and in particular considers deadrise angles of Benedicts, Cross's etc.  If you are at the Institute you should be able to find it in the library, thats where I got my copy.

There is also a book by Pierre Gutelle on yacht design that also considers dinghy shapes, especially foils.


Posted: 06/12/2006 23:44:16
By: David G
This link to Keith Callaghan's site is helpful for the 1970's

http://www.bluelightning.co.uk/Merlins/merlins.htm

Posted: 07/12/2006 08:53:33
By: Andrew M
On the subject of Tasar rigs its worth noting that the Tasar rig was a huge compromise. The hand built wood masts on NS14s and Cherubs that Bethwaite made were longer in chord: 4 inches, maybe a little bit slimmer and much more flexible. That was sone by making the front half of the mast non structural balsa. They were still pretty heavy though. I'm sure the same trick could be done with a carbon section and some kind of polyurethane foam for the fairing. The Cherub rigs carried spinnakers just fine, but the hoist was not very far above what were already rather low hounds for the class.


Posted: 08/12/2006 18:06:50
By: JimC

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