what size motor

powerwagon

Cadet
Joined
Apr 27, 2009
Messages
8
How well would a 20 hp motor push a 17 foot lonestar fiberglass boat ? or what would min size be for this boat on the river? Thanks.
 

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,392
Re: what size motor

Not familiar with the boat but how heavy is it ?? and what type of hull formation ??
There is usually a plate on the boat with the max hp rating. Realistically you should be at around 70% of the maximum for reasonable performance.
 

Jeep Man

Commander
Joined
Oct 17, 2008
Messages
2,803
Re: what size motor

20 hp would make for a sloooow ride. 17' glas should be a 40 hp at min., but I suppose it depends on what your using it for and how many passengers.
 

Willyclay

Captain
Joined
Sep 8, 2006
Messages
3,264
Re: what size motor

If you cannot determine the maximum horsepower rating for your boat by any other means, you can use the USCG formula to calculate it. Try this link:

http://edocket.access.gpo.gov/cfr_2004/julqtr/pdf/33cfr183.53.pdf

The Power Factor (PF) is length times width at the transom in feet. The other variables are hull design (flat bottom or others), remote steering (Y/N) and transom height (at least 20 inches or less than 20 inches).

Good luck, be safe!
 
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David Greer

Petty Officer 1st Class
Joined
May 7, 2006
Messages
219
Re: what size motor

When you say river I think current even though my rivers are tidal. I think your rig sounds dangerous if you encounter dirty weather and have to go up or cross stream.
I see a guy on my river with a 16' beat-up free runabout with a small motor like that but ALL he does is use it to dinghy out to his sail boat mooring--smart move-- a lot cheaper and roomier than a zodiac! So if you had extremely limited use like that--a work boat around a marina, maybe so.
 
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