Bristol 24 auxiliary power

[JeremyD6697]

I recently purchased a '68 Bristol 24. It came originally with an inboard engine which a previous owner removed. I have no interest in replacing the inboard due to cost restrictions but would like to put in an outboard. It has a well in the lazerette for an outboard motor. My first question is, due to the outboard being in the well and not on a kicker bracket, can I get away with using a shorter shaft motor? Secondly, what kind of horsepower is needed to move the boat at hull speed? Obviously a larger motor is better to a point, but again cost is a concern.

Thanks for the help

[camaraderie]

Yes...you can use a short shaft. I would guess that a 7.5hp engine or thereabouts would suffice. Less...if you are lake sailing and don't have to worry about tides, currents and larger seas.

[soulesailor]

7.5 is probably enough to get up to hull speed but you certainly can get by with a smaller engine if a nice model comes up for sale near you. I motor my 68 B27 with a 6hp and it goes about 4 knots with ease, not pushing it at all. In the ocean with waves and current it might be 3 knots. How long do you plan on motoring? If there is wind put the sails up. The short shaft will work fine in the lazarette well, like Cam said.

[JeremyD6697]

I don't plan on motoring for long, just enough to come in and out of port, in and out of the river where the marina is located, and on the odd chance we have a windless day on buzzards bay.

I was originally thinking of a 9.9hp, but I've recently found 2 6hp 4 stroke models in nice shape for great prices. Just wasn't sure if that would be enough.

[sailingfool]

I would also think the 6 HP would be adequate for the boat size ( I had a 4 long shaft on my 23' and that served fine...), but I would get a long shaft as outboards have generally marginal prop depth, and deeper is, well, always better. Also note that the 4 cycles are bigger than the 2's, be sure to check fit before you are commited.

Here's a link to a discussion thread about outboards and Cd 25s, while the CD 25 is a different boat I would think you would find it helpful to read the comments of these owners of a similar sized boat: Cape Dory Boats - View topic - best 4 stroke and horse power outboard for 24 ft CD

[Carleton70]

I have the 9.8 and can get on plane! -- seriously, I wish I had a lighter motor. The 9.8 fits nicely in the well but an 8hp would fit and be easier to remove etc. I have the 25" shaft and find that effective even in a heavy chop; never had cavitation even in the worst conditions. Of course, having that "hogleg" sticking deep in the water invites Chesapeke crabpots to attack!!

I would think the 8 hp would do the job. I wouldn't be interested in anything smaller because I am often in strong currents, steep chop entering and leaving coastal areas. If you transit the Cape Cod Canal or similar area you really appreciate more hp.

[JeremyD6697]

Originally Posted by Carleton70

I have the 9.8 and can get on plane! -- seriously, I wish I had a lighter motor. The 9.8 fits nicely in the well but an 8hp would fit and be easier to remove etc. I have the 25" shaft and find that effective even in a heavy chop; never had cavitation even in the worst conditions. Of course, having that "hogleg" sticking deep in the water invites Chesapeke crabpots to attack!!

I would think the 8 hp would do the job. I wouldn't be interested in anything smaller because I am often in strong currents, steep chop entering and leaving coastal areas. If you transit the Cape Cod Canal or similar area you really appreciate more hp.

The canal is about the only reason I'm afraid to go too small. I've seen too many sailboats standing still in the canal.

I still haven't committed to one yet. The boat goes in the water next weekend, so it's crunch time in finding one.

[SOUNDBOUNDER]

I had an 8hp on my B24.
It was more than enough for moderate currents.