How many horses for 100lb 17ft cedarstrip skiff.

[don ruperto]

Just finishing a stretched Rice Lake Skiff 17ft which should weigh just over 100lbs. Problem is I will often be coming out of Rye Harbour against a 4knot tide so will need 8+ knots to get home in time for a pint. I was hoping 5 hp Yamaha 2 stroke might do the trick.
I do not want to buy the wong engine.
Tks Rupert

[JimD]

Don, I'm assuming you weigh more than the boat does. What do you expect to be the actual displacement fully loaded?

[Donn]

What does the designer suggest?

This, I believe, is a 13' 9" model:

http://www.bearmountainboats.com/gallery/RiceLake/RiceLake01.jpg

Lovely design, by the way. Do you have pics of your stretched version?

[don ruperto]

I would expect total weight to be between 600 and 700 lbs

[Alan D. Hyde]

We used to have a 7 hp motor on that size boat.

It worked well, and wouldn't have had a problem with that current.

Alan

[Joe ( Cold Spring on Hudson )]

My skiff is about 200# and I just ordered one of these.

http://www.honda-marine.com/images/BF2_engine.jpg


Honda's 2-horsepower engine is the lightest four-stroke outboard motor in the world. It delivers the power and smooth, comfortable operation your customers need in a small, easy-to-handle package. The 2 HP BF2 is extremely low-maintenance, with a transistor ignition that makes it easy to start...and a forced-air cooling system that eliminates the need for a water pump. Im thinking of giving it a try on Dove which is a bit heavier.

[Wayne Jeffers]

Assuming a water-line length of 17 feet, hull speed would be about 5.5 kts. A 2 hp outboard should easily push it to that speed.

If you want 8 kts., you're gonna have to give her a lot more power to get her near/on plane. This may be a problem if she's like the boat in the photo Donn posted. If she's a skinny round-bottomed boat with a skinny round section back near the transom, more power may just push her transom down into the water with little gain in speed. If she's skinny enough back near the transom, she may not carry the weight of a much bigger engine without pushing the transom way down, even sitting still.

What does the designer say about her maximum speed and the maximum engine size she'll carry?

Wayne

[RonW]

I have kept quiet so as not to receive a blast of sh*t. But I was going to suggest the little 2 horse 4 stroke honda as well. I have a 450 lb river dory with a 6 horse 4 stroke tohatsu.
Half throttle takes it to about 8 mph and the second half of the throttle may add a 1/2 mph more. You will be taking it off and on every time you use it, my 6 horse is advertised as 58 lbs. and it is with out a doubt the heaviest and most awkward 58 lbs I have ever seen. 2 stroke may be a different story, but 4 stroke is nice, particularly for a small putt around fishing boat.

At a hull speed of 1.3 it is 500 lbs per horse, so a 2 horse will shove a 1,000 lbs to this speed, which in your case is 6.16 mph. long ways from 8 knots.Take the pint with you and drink it on the ride home.

[Donn]

"Take the pint with you and drink it on the ride home." :D

[Mark Van]

If the boat was designed for planing, a 5hp would probably just get it on plane. If it is a displacement hull, I wouldn't bother with anthing more that 2 or 3 hp.

[don ruperto]

Thank you all for your help. Most of the work will be on non tidal rivers like the Thames which has a 5 knot speed limit. The 2 HP Honda sounds good. Better to be going somewhere slowly, than nowhere fast.
I do not believe the boat is at all suitable for the open sea. Very little freeboard towards the stern. At least the sea is only about six foot deep half a mile out.

[Meerkat]

Originally posted by don ruperto:
At least the sea is only about six foot deep half a mile out.Which is not a problem if you're 7' tall - but mind the gaps! ;)

[Alan D. Hyde]

Actually, waves in shallow water can be much steeper, frequent, and more threatening than they would be in deep water.

Alan