Thursday, March 1, 2012

Re: [Electric Boats] Re: Newbie Question- Converting a 45' catamaran

 

Thanks, Andrew, for the Yanmar diesel outboards idea. I did look into them and thought that they had stopped making them as I have seen no recent activity mentioning them. And then the price and small props, short shaft etc. put me off any further investigation. Ruggerini in Italy also make a couple of 15 and 25 horsepower diesel outboards - aircooled with small props and short shafts as well. I actually ended up buying one of those Chinese agricultural-looking 10 horsepower air-cooled outboard motors (Star). I then decided that it was too little power and would end up frightfully noisy. But I still have it and am not sure if I am going to take it along as a back up :) - probably overkill seeing I already have 2 Kubota engines installed now.
 
Thanks for the photos, Chris. Gives me an idea of what the long tail arrangement looks like. In my mind I had always thought of it as a hinged engine box-and-shaft arrangement all mounted in a straight line on a swing-down box. Although doing the calculations just now I see it would have to be a pretty long tail to get it reasonably deep in the water - if the bottom of the box and the 'hinge' is 600mm clear of the water and you want the prop centre 400 - 600 mm under the water at a no-more-than 12 degree angle then it means the whole arrangement is getting close to 5 or 6 metres long. So perhaps a universal joint is the better idea. Electric motors with a diesel generator may give more design options?
 
And then again perhaps there are many more arrangements that are possible if you are an engineering type with lots of money - converted outboard legs, z drives, belt drives etc. But it proved beyond me at the time I had to make my engine decisions (lots of white hairs after those decisions!), so I ended up mounting my Kubota engines down in the hulls close to the centre of flotation with straight shafts coming out the bottom of the hulls. A compromise as far as sailing drag and barnacles on the props, but I will live with it. Perhaps on my NEXT boat ......- hahaha.
 
 
----- Original Message -----
Sent: Thursday, March 01, 2012 9:23 AM
Subject: Re: [Electric Boats] Re: Newbie Question- Converting a 45' catamaran

 

Andrew et al

I've now put up some photos in an album called Long Tail Cat, which is no doubt is some kind of rare and endangered feline not to be trifled with.  But this album is really about a type of shaft drive reminiscent of the long-tail boats of Thailand. There's plenty of photos with details about how Owen Easton sets up his cats using this kind of shaft drive.

Cheers

Chris

On 29/02/2012, at 5:23 AM, And&Hanna wrote:

 
 

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