MERLIN ROCKET FORUM

Topic : Rudder Modifications

Hi

We've just bought 3146 (Sledgehammer), and are currently getting used to it on our small lake. However - depth is an issue. Our lake is no more than 3 ft deep over about a third of it's area, and we've got problems with the rudder being too long.

Tomorrow I'm hoping to do a small non-permanent downhaul mod with a few pulleys and rope/bungee, but if we decide to keep the boat permanently and persist we need to do something a little more permanent, i.e. use a smaller rudder, even though this will affect handling etc.

Our current two options are:

1) find a rudder off another boat with a similar stock that would fit, or
2) use the shape of the current rudder, altered, to design a template for a smaller rudder which I'd make out of marine ply.

Has anyone got recommendations on either of the above? Never made a rudder before, I'm sure it won't be easy, but I'm willing to give it a try. A friend of mine has a friend with a hinged rudder, so the entire blade is lifting as usual, but halfway down the blade the entire blade hinges as he also sails on a smaller lake - but this strikes me as the most difficult option of all.

Regards
Richard H


Posted: 17/10/2009 23:44:37
By: Richard H
Nobody has done it in merlins yet to my knowledge, but a daggerboard style stock would be the best option. Larks and N12s use it so you could copy one of their blades.


Posted: 18/10/2009 07:43:44
By: Chris M
Richard,

I used to sail an OK at Crawley Mariners YC, similar problem 3' round the edges, bout 6' max in the middle (handy if you capsize)!. I made a rudder stock with a self lifting system with bungee etc,etc. Seemed to work very well. I have an image of it somewhere which I can forward to you, or i'll post it to Mags (website manager) and he can stick it somewhere on the website.

I plan to sail my Merlin 908 at CMYC and will be faced with the same problem so will have to adapt the rudder to suit.

ATB

RichardB


Posted: 18/10/2009 08:10:03
By: Richard Battey
hi.I have experienced similar problems on a river. I now use a fireball rudder which works well. you may want to use a shorer but  fatter rudder. the enterprise circit always used to use ovalled rudders in heavy winds due to more control when theirs more power.


Posted: 18/10/2009 08:49:45
By: jon
I fixed up a 2:1 downhaul secured through an auto release clam cleat on the tiller. When the rudder hits someting it just pops open - no damage. Haven't had any premature releases either!


Posted: 18/10/2009 11:11:12
By: John
I would find a deeper lake, or stay on the bank and sail a radio controlled merlin.
However if the rudder is too long surely the center board is also a problem as it is longer?


Posted: 19/10/2009 19:31:17
By: john
Chris M: but then we'd have to have a rudder blade that would be short enough for the shallowest depth as we'd have to lift it in and out, we definitely need a hinged/lifting solution of some sort.

Richard B: Had a tinker around with the rudder tonight, just trying to jury-rig a temp solution so we can sail it and try it out, with a couple of small pulleys arranged from the tiller/rudder pintles. We'll see the weekend hopefully how well it works (or not)

Jon: We've got a few enterprise rudders hanging around at our club, so I may try to borrow one and try it, I suspect the tiller extensions won't be anywhere near long enough though.

John: yep, centreboard won't work well either, that's easier though as I'll just rig up a piece of rope+bungee going to one of the many jammer cleats we have, to hold it down.


Posted: 19/10/2009 21:49:38
By: Richard H
Richard B: if you want to send the image, send it to the email address I'm posting with, and many thanks.


Posted: 19/10/2009 21:50:21
By: Richard H
Hey - where do I get a radio controlled merlin rocket? could solve all my crew problems.


Posted: 20/10/2009 14:41:07
By: JohnG 3502

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