What auxiliary engine

[Philiz]

do the forumites think will best suit my needs?. We have a Merry Fisher 625 which is fitted with an auxiliary engine mount. I'm thinking of getting a small engine for back up but want to get as smaller one as possible which will get us out of trouble if the main engine fails, but will be light enough to man-handle for use on an inflatable tender which I hope to get later. Most seem to have a 6HP but I'm wondering if I can get away with something a bit smaller and lighter?

 

[ontheplane]

Go for a sailpower - there are lots of posts on here about it

Try searching for "Sailpower" you'll pull a few up then

I would think a 4hp sail would be enough for you - the sailpower engine is designed to give thrust not speed...

 

[Ripster]

Figures used are you want about 1hp per M. So 6 is prob about right for yours using a std outb. But good advice on the sailpower engine.... tghis route may allow you to go a bit lighter. As has been said, there are many posts on the sub - one chap tried a range of HPs and once you reach a certain speed where to go quicker you start to plane... a few more hp did not make a lot of diff to a steady disp rate - say 6-8kn

a 2hp motor will push you along in a clam sea - but against tide/current/windage - then this is where the thrust based sailpower's come good.

 

[Haven't-a-Clue]

I too have a MF625 and have been wondering if I should put my 8hp Honda as an auxilliary engine. It is a tad heavy at 50kg........... however, where could I get a high thrust prop for it, 'cos I reckon it might do the trick with one of those. More to the point, where could I get a suitable mount ie what type of mount should I look for and what is it liable to cost? I'm fairly handy with tools and such so would like to try fitting it myself if that's a good idea (or not, I dont know).

 

[MVP]

We are using a 3.3hp 2 stroke mariner from our old boat on our QS 640 Weekender. Tested it last year in Langstone, about 3mph on the GPS if I remember correctly, with 6-up and against the tide.

We were quite surprised at how well it coped - depending on what you expect, this is a very lightweight option, and being 2-stroke you can store in laying down.

MVP

 

[longjohnsilver]

If properly serviced the chances of the main engine failing are very very small. Therefore your auxiliary will probably never be used so I'd get as small an engine as possible. Why carry around all that extra weight for nothing? And use the savings to make sure enginew servicing is done properly.
I've had single engine boats for about 20 years, crossed the channel many times and never carried an auxiliary. Only had a problem once when a fuel lift pump gave up the ghost and after that made sure I carried a spare and reviewed all the spares I was likely to need at sea. And made sure I had some idea how to deal with any problems and carried a comprehensive tool kit. All more important imho than a spare engine.