Ribcraft 585 Auxiliary Engine?

[JABS]

I have just bought a second hand Ribcraft 585 with a Mercury 90hp. I would like to carry an auxiliary for offshore trips. What size of engine do I need? I don't need to be able to necessarily contnue at speed, just get home or to safety. I would prefer to use a four stroke so that I can use the existing fuel supplies?
Any comments or advice would be very much appreciated.

[BogMonster]

When I asked the same question a few months ago I was quoted 1hp per metre of boat as a general rule of thumb, and I therefore have a 6hp Johnson 4 stroke long shaft on my Humber 5.8. Having been out in a bit of wind with it, I'd not like anything less.... in a 20kt (ish) wind I get about 4.5kt into wind and about 5.5-6kt (GPS readout) downwind, but the real issue is not speed but control of the boat when the wind is catching you side-on, and it's a struggle to keep anything like a straight line even with the 6hp. You'll need to measure the transom to check shaft length, probably long shaft required as I doubt a standard short shaft will be long enough.

I bought a 4 stroke for the same reason, so I don't have to carry pre-mixed fuel on board and then worry about whether it has gone "off" or not. Lovely little engine (built by Suzuki and the same as the Suzy 6hp) if unused for a few weeks it needs 4/5 pulls to start it, and if its been running that day it starts first pull almost every time.

[vince]

WE have a 4hp mariner 4 stroke which pushes along nicely at "get home speed." When its really windy, lock the aux in place, and use the wheel as normal, a bit more drag, but much better steering response.

[JABS]

Thanks guys. Since more is better, I guess it will be 6HP!

[codprawn]

I would be tempted with a 2 stroke - stands up to the abuse an aux gets better. Also they are stopping small carb 2 strokes so should be some good bargains about. A Tohatsu 9.8 would be ideal and is very light.

[BogMonster]

Originally Posted by codprawn

I would be tempted with a 2 stroke - stands up to the abuse an aux gets better. Also they are stopping small carb 2 strokes so should be some good bargains about. A Tohatsu 9.8 would be ideal and is very light.

What are modern two stroke hand start engines like to start? I know with Dad's old seagull when I was a kid, you needed to think about starting it the day before, to stand any chance of getting away vaguely on time

can't get better than my 6hp four stroke for starting and I think thats important for when you need it in a hurry!

[codprawn]

Well my chainsaw starts first pull no matter what the weather!!!

[BogMonster]

Originally Posted by codprawn

Well my chainsaw starts first pull no matter what the weather!!!

Ah I see, so when your inflatable deflates you can teach the f***er a lesson? Sound thinking, in fact I might buy one myself

[Polwart]

Originally Posted by codprawn

I would be tempted with a 2 stroke - stands up to the abuse an aux gets better. Also they are stopping small carb 2 strokes so should be some good bargains about. A Tohatsu 9.8 would be ideal and is very light.

I think you might be wrong... many yachties prefer 2-str (for various reasons - not least the storage on the side factor) and so there are rumours that people are buying or planning to buy 2str engines before the "ban" and will then sell them on after the ban (as second hand so legal ) at a profit.

[ScottyDog]

With so many engine failures being attributed to fuel problems maybe having another fuel source for a 2 stroke outboard is not such a bad thing. Most of the 9.9 Hp models are also available in 15 Hp with the same weight. An extra knot may just make the difference between getting back against a current and not getting back at all.