Motor Size Matters

[curlie531]

Hi, folks. A question about motor size. I have a 20 sailboat (1973 Ensenada 20) 1600 lb. displacement and I'm wondering if my recently purchased 9.8 hp 85lb motor is too much. It's quite a bit larger than I expected. Any rules of thumb I should know here? I wanted more power than my 3 hp since we're moving from a small enclosed lake to Lake Erie, which can change moods in a hurry. Thanks.

[foamcore]

Who says it is too much? Too much what? Power or weight? Seems to me that 10 HP is fine for a 20 foot boat.

[kenjh]

what problems are you haveing? we are running a 9.9 on a 12 foot runabout and a 15 Hp sailmaster on a 30 foot Shark sailboat...you can never have too much power..to small a prop yes..never to much power !! just finished up a vw diesel in a 35' Coranado 9.8 knot's in a calm sea !!!with 40 hp

[wolfenzee]

I consider an engine on a sailboat as a piece of safety equipment, not just something to get you back to the dock when the wind dies, but something to keep you off a lee shore in a nasty blow and get you home....possibly even give someone else a tow. It may to heavy a motor, but the horse power is fine for you application.
I have a 33hp diesel with a 16" prop, but I also have a 30' 15,000 ocean cruising boat

[Jimbo485]

It all depends! Haha, how is that for a useful reply?

Seriously, we have a 40' cat with a 23' beam and have twin 8 HP outboards in wells. When motoring in a crowded harbour, we use both for a grand total of 16 HP. When motoring in a straight line, we use just one and putter along at somewhere between 2 and 6 knots depending (!) on the conditions.

Go small and it will improve your sailing and planning abilities with early morning departures with the land breeze etc.

[wolfenzee]

at 2200rpm I cruise along at 7knots....in a 20kt headwind with 4-5' seas that drops down to 6.5kts(40kt headwind with 10-15' seas that drops down a about 4knots).
I also have a 1.2hp outboard that will push my boat at almost 3kts in a dead calm.

[cal40john]

Our club had a Bristol Caravel 22, 2850 lbs displacement and an Islander Excalbur 26, 3700 lbs displacement. Both had 6 hp motors on them and they had plenty of speed. The times that they couldn't push the boat at a reasonable speed, extra horsepower wouldn't have helped as the prop was out of the water too much of the time. I'm pretty sure the Bristol originally had a 4 hp, but making all the engines interchangeable won out.

If you had an inboard with the prop way down deep in the water then putting a large engine on your boat could be argued as a good thing to do. I don't think a big outboard setting your boat out of trim to make it sail worse for something that is likely to be useless in big winds and waves a good tradeoff.

Particularly remember trying to leave a marina with the 26 having to turn around back behind the breakwater, get the sails up and sail out upwind because the engine spending more time screaming in the air than staying in the water.

John

[zeehag]

i used a 6 hp LONG SHAFT on a columbia 26 eons ago. was perfect. my 35 has a 20 hp yannie -- is perfect.

[GordMay]

Greetings and welcome aboard the CF, curlie531.

One rough Rule of thumb for determining Horsepower Required for a Sailboat :
one horsepower per 500 pounds ( ± 50lbs ) loaded.

For more information, opinion, and discussion:
See ➥ http://www.cruisersforum.com/forums/...size-1577.html
And ➥ http://www.cruisersforum.com/forums/...vise-9883.html
And ➥ http://www.cruisersforum.com/forums/...zes-24283.html

[curlie531]

Thanks for the input. I'm new here and fairly new to sailing and am quite impressed with the informative responses. The boat and the new motor have not met, yet. My concern is that I overbought, since this motor is 50lbs heavier and MUCH larger than the old one. I hope to get a bigger boat next time around, so I bought a bigger motor (sight unseen)with that in mind and suffer a bit of buyers remorse. I think it'll be fine if the bracket holds up.

[perchance]

The only downside you may encounter with the extra weight and HP is that the boat may squat a little more under power. My 26' does just that with a 9.9.

[blgklr]

I would say 6hp would be fine, but as you say you plan on moving up later keep the 9.9. Keep eyes open 4 a killer deal on a six that can go with the boat when you move up and the 9.9 for that 4000-5000 # boat.