Hi Chris. I think this is an absolutely beautiful idea. I have been thinking along these lines for a long time. I desperately wanted diesel outboards for my catamaran, but could not find anything remotely suitable.
The advantages of this mid-bridgedeck long-tail arrangement are many: Compared to outboard motors, with this arrangement you get the economy of diesel, the battery charging capability of a full alternator, can put a big pushing propeller on the engine and put the propeller as deep in the water as you wish to have it. The central weight distribution is also better than the normal aft-engine arrangement. The regular marine gearbox that you use on the engine is a lot cheaper than the sail-drives that are normally used on catamarans.
And then you get most of the advantages of outboards - you can lift the prop out the water when you are sailing or at anchor, you can drop the engine off the boat for major work without having to pull the boat out the water (although with a cat you can beach it reasonably easily anyway - but still on conventional diesel installations prop and shaft work has to be done between tides) and there are fewer holes in the hulls - just need a through-hull if you wish to suck the cooling water up through the hulls. Unfortunately the layout of my bridgedeck and saloon was already done and did not allow for an easy conversion to this arrangement of engines. But glad to see that someone has actually done it this way.
Cheers
Andrew
----- Original Message -----From: chris BakerSent: Tuesday, February 28, 2012 5:33 AMSubject: Re: [Electric Boats] Re: Newbie Question- Converting a 45' catamaran [1 Attachment]Hi SeanHere's an idea that may help you keep the props out of water, and be easy to build from off the shelf parts...This idea is from Owen Easton, a cat designer/builder downunder. Its kinda like the long tail boats in Thailand where you have the prop on the end of a long shaft that hangs out the stern of the boat. But on a cat you can use this idea between the hulls. The motor is amidships for good weight positioning and the props fold up towards the centreline of the boat under the bridge deck. In owen's designs the powerplant has been two ICE engines driving this prop shaft through a universal joint.I have some photos of this setup and will put them up soon when I take a look at how to do that. I'll paste a photo here but I expect it may not show up.
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