40 Horse Outboard on Catalina 30?

[jongleur]

Is there any reason for not putting a 40 horse
outboard on a Catalina 30?

C30 is 10,200 Lbs with 4,250 Lb ballast.

Weight and trim issues, I can understand.

Any other areas of concern?

[cal40john]

Waste of fuel. Probably takes less than 10 hp to get to hull speed in flat water. If you're thinking you want more hp to power through waves you'll have the problem of the engine more out of the water than in.

[sww914]

It won't go much faster with a 40 than a 15 but if you already have a 40, why not?

[jongleur]

Good answers. Thank you.

I can get a good 40 pretty cheap.

But then what would be optimal for
a C30 outboard?

[sww914]

Are you from Morro Bay, Bill?

A 40 is pretty hard to lift.

Any way, upon reflection,a 40 is a hell of a lot easier to lift than a Yanmar, isn't it?

[ohdrinkboy]

the c27 i race on has a 9.9 and it works fine.... ever hear of hull speed?

[cal40john]

Don't know exactly for outboards. Most are designed for high speed, if you get a high thrust version it would probably be close to the values below.

Skene's calcs show about a 20 shp engine for your boat, this includes adding 1/3 more S.H.P. than needed to make hull speed. I used 30% for prop efficiency (outboard probably should use lower eff.).

Rules of thumb vary.

In a different time Hiscock said all you need is 1 hp per ton (long), that's 5 hp for you. This is only good for getting in and out of marinas at less than hull speed. Hiscock thought 3 hp per ton was the biggest engine you would ever need, that's under 15 hp.

For sailboats, Ted Brewer states that "3-4 bhp per ton is adequate, 5 bhp per ton is ample and 6 bhp per ton is often too much."

So about 23 BHP using 5 BHP/ton, assuming he means long tons.

[GILow]

Surely having all that weight out on the stern would be a problem? Not so much a trim as a momentum issue.

[skipmac]

My concern would be whether or not the transom could support the weight and thrust of an engine that size.

[thomm225]

Many experts recommend 2 hp per 1000lbs, but I have a 5hp (57lbs) on my 6600lb Bristol 27 which does ok. It looks tiny back there which is good. Sailboats look bad enough with an outboard even worse with a large one hanging off the stern.

A 9.9 - 15hp 4 stroke would probably work fine for you, but get the longest shaft you can. I have the extra long 25" 5HP Mercury 4 stroke on my boat. The 9.9hp weighs 85lbs; the 15hp weighs 136lbs.

Btw, these new 4 stroke outboards are as good as a diesel on fuel economy...............

[jongleur]

Thanks.

Maybe I should buy the 40, sell it and get a
newer 15?

[Hud3]

Something to consider is that an outboard will come out of the water in certain windy, choppy conditions, limiting it's ability to push the boat. A friend of mine ended up on a New Jersey beach because of that phenomenom.

[Cotemar]

What is wrong with the 10 hp diesel that was inside the Catalina 30?

[Hillbillylad]

I have a Honda 9.9hp 4 stroke on mine. High thrust long shaft. Uses less than half a gallon an hour. Pushes the boat just fine and haven't had any real issues with cavitation. I guess when those choppy waters are usually wind driven your sails are up right?
Biggest pain for me is no remote controls to the cockpit and I have to lean back over the stern to adjust the throttle or change gear. Not a big issue en route but a pain in the backside maneuvering into slips etc.
I think a15hp might be a better choice for that extra power when needed if it didn't make a massive dent in the fuel consumption or weigh too much.

[The Garbone]

Too bad your in California, I would sell you the Honda 9.9 4 stroke off my C 30 real cheap, just come and take it off the transom and I will even throw in the bracket.