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cb32863 05-12-2010 03:00 PM

OUtboard sizing question
Going to be looking at an O'Day 25 centerboard this weekend. Does not have a motor. I have found that the max HP is 15 for this boat as per the specs but I am wondering what would be a recommended size for this boat? Would be sailing lakes if that helps. Possibly in the future up in the Apostle Island area as well.


eMKay 05-12-2010 03:07 PM

Sailboat calculator says 8hp minimum for hull speed, so a 9.9 would probably be perfect

cb32863 05-12-2010 03:19 PM

eMKay, thanks! That's a handy site.

dabnis 05-12-2010 05:37 PM


Try this:

Covers it pretty well.


eMKay 05-12-2010 05:53 PM


Originally Posted by dabnis (Post 603165)

Try this:

Covers it pretty well.


That thread seems to be about Catalina 27's, and O'day 27's. Both much heavier than an O'day 25, not sure how you think it's relevant.

dabnis 05-12-2010 08:04 PM


I had posted re my experience with a Coronado 25. Long story short,had a 6hp and it was marginal for SF Bay conditions except for dead calm conditions. Went to a 15hp, same size and weight as a 9.9hp, the 15 would drive the boat as fast as it would go against heave wind and seas. A 9.9 may have been OK, bottom line, the 15 flat got the job done.


mstern 05-12-2010 08:21 PM

I had a 9.9 two stroke on my Oday 23 before I repowered, and it was a bit of overkill. It should be fine on a 25. But if you buy a new outboard, it's going to be a four stroke; they just don't make two stroke outboards that small anymore. Here's the deal: a four stroke generates more torque than a two stroke, so you can usually get away with a smaller (lower hp) engine. The flip side of that is that the mounting bracket on your Oday 25 is probably not rated to handle a four stroke. Is this a big deal? Its been endlessly debated here and elsewhere. I don't know, but I wouldn't chance it. It's not just the weight of the engine that is at issue, but the extra torque generated by the four stroke engine that could put the mount (and your transom and engine) at risk. I just don't know enough about engineering to say if an 80 lb four stroke on a bracket that can handle a 110 lb two stroke is ok. One thing I can say for sure: get the longest shaft model you can find. The "standard" length of a long shaft is 20", but some manufacturers offer a 25". Go for it. It's way worth whatever it costs. My long shaft model (20") pops out of the water in even a modest chop.

bacinmass 05-18-2010 12:13 AM

I have a 15 hp Mercury on my O'day 26. Former family boat was an O'Day 25 with a 9.9 Johnson. There were times when the 9.9 just couldn't hack it against a tide in a fast-moving river. With the 15 hp Merc, it seems to be a great combination for my coastal sailing. I have noticed that the motor mount was probably reinforced sometime late in the boat's life (I've owned the 26 for 2 years). Based on mstern's observations, I'm glad that the PO did that work. Bottom line, I'd recommend careful evaluation of what the motor mount can handle weight/thrust wise. I don't know what the conditions are like where you'll be sailing, but I'm thinking that with lake sailing you'd be ok with a 9.9. Did you decide to get the boat?

cb32863 05-18-2010 07:23 AM

Thanks for all the info. Checked the boat out and two words.... soft deck. Actually was very soft in some places and I don't want to get in to a project right now.

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