Catamaran Evolution

Ian Farrier has scaled something like this to 33-ft trimarans. The rudder blade is held in a wrap-around composite sleeve that is open at the back. The open edge is held together with nylon bolts. The blade slides up and down in the sleeve like a dagger board.

If the rudder hits something, the nylon bolts will shear and the blade can spring open the rudder head and come out the back. The blade-holder can also be mounted to an outer cassette so it can kick back while still being steered.

 

Hammerhead looks like a nice design, I like the look of the 54'.

 

Like a dagger case hinged inside a normal tilting rudder frame ? Yeah I can see that working, it would be good if you had some sort of resettable friction mechanism as apposed to a sheer pin type arrangement. Thanks for that, I think it just got added to the wish list!

 

Damnnn

Thanks Tom...

Didn't see that before. Very nice and clean.

J

 

Hello Richard...

Okay, but be careful with how much electrical comfort you incorporate since amps are at a premium.

Also...you may need to have the control grip and components custom made in a more salt water friendly metal such as stainless and the wiring will also have to be upgraded to tinned as will all connections. I think it will be expensive (probably not so if compared to 2 steering statios with pedestals etc.). Either way, it will be worth the comfort and effect. Obviously, the same would have to happen for the throttle grips for the engines...in my case anyway...since it will have to be a "complete" set-up.

I have been trying to find drawings for both the Cougar stick and throttle to take to a machine shop for estimates but it seems to be classified. If I find something I'll post it.

I also like the idea of controlling everything from one position and it is a pretty cool idea.

J

 

Agreed. For a system like that, only the best is good enough. Non-corrosive all the way. And ofcourse, all functions should have manual over-ride

 

OK Tom I missed the link, very similar colour to the text on my monitor. That's not what I conjured up but hey thanks for the stimulus, looks neat though.

Cheers
MBz

 

http://www.thomson.ece.ufl.edu/lightning/

J, have you given much thought to lightning hazard? I don't like the idea of a fighter stick now. You are holding on to a conductor. You can still have evrything electric, but I would prefer to use a nearby control panel, rather than having all the wiring connected to my hand. All the major metal fittings on the boat should be connected to each other with wire to stop lightning arching from one thing to the next, and the bulk of the lightning should be channeled down the mast to large metal panels on the bottom of the boat.

 

I guess Rick would know something about this...he's an electrical engineer

 

Hello Richard,

Automatic my friend. First there is the "cone" of protection afforded by the mast which produces a diameter at the waterline equal to its height. Then there is proper "grounding" of all electric conductors and components. Then, the fighter stick is lower than a lot of other metal items. Then, the fighter stick grip is not metal. Then there will be 4 gage copper wires that connect to the shroud cables that can be thrown over the side during "lightning" conditions. Then everyone can just head below and leave the autopilot on as a sacrificial if anything is to get whacked. Then there is a tender that everyone can jump into and be towed by the Green Lantern until the storm subsides. A couple of other things I can't remember.

If all fails, and believe me it still can, the path of least resistance will dominate and all the electronics and electricals will get fried. Well, except for the back-up electronics which will be wrapped in aluminum foil and well away from any electrical connections or metalic objects.

There is also the fribilator in the first aid kit just in case.

What do you think? Did my paranoia give it any thought?

J

 

Wow You've really thought about it. I think you can never be too careful when you are standing next to a big lightning rod with nothing else for miles.

Grounding the shroud cables won't stop the lightning from traveling down the mast and blowing a hole out the bottom of your boat. The bottom of the mast is where the lightning needs to be evenly dispersed, according to this thing I've been reading. Don't rely too much on theories of 'least resistance' because lightning cheats a little bit. Everything becomes so charged that you start to get little lightning fingers dancing around the boat. I think the idea of attaching wires between all the major metal parts, is to create specific routes for these 'fingers' to travel along, instead of letting them dance around looking for someone to tickle.

 

So do I - I wish I could afford one!

 

was thinking your nursing a rather nice Farrier Tom, money, here too is too tight to mention but we can dream cant we
coming back on my post 103 and 106 bout filling stern well with tons of water i see Guilermo posted a explanatory junk site

 

Hello Tom...

Gotta apologize. I missed this post altogether.

I cannot even tell you how much I was wracking my brain about trying to figure out the geometry so that the length of the cables did not change when the rudder kicks back. Also, I couldn't for the world of me figure out how to keep the rudder from slamming the stern.

I really appreciate this information. One question. Is it possible to conceal the entire apparatus without having to set up a skeg or is the skeg absolutely necessary?

Thanks again,

J

 

Hello Yipster,

I'm not sure I'm interpreting correctly, but if the junk design holds some water in the stern to prevent her from burying her bows until the following wave passes, then it is good for me to have the transom steps take on some water and evacuate when the wave passes also...yes?

J