What HP motor for 21ft aluminum boat?

doclynne

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Jan 30, 2003
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We are having an Alumaweld type boat built. It's a "Rogue". It will have 18" full V bottom, 4 lifting strakes and 34' sides. The dry weight of the boat should be about 2800 lbs, not including whatever motors we buy, or fuel, passengers, etc. We were hoping to buy a 4 stroke, but the boat builder thinks that perhaps a 140 hp won't quite do the trick and then they jump up to 200 hp. Of course, the price jumps up quite considerably, too. Does anyone have any suggestions? Are they making 2 stroke motors that are just as fuel efficient? :confused:
 

roscoe

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Oct 30, 2002
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Re: What HP motor for 21ft aluminum boat?

4000# is a lot of weight for a 140 on a deep v to get up on plane. How much is the boat rated for? I would get closer to max hp rating. I would hate to spend that kind of money and be underpowered.<br /><br />May want to look at i/o, or a couple of 115hp.
 

JB

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Re: What HP motor for 21ft aluminum boat?

Hi, Doclynne.<br /><br />Go with the HP that your maker recommends.<br /><br />Most of the direct injection big 2 strokes are as fuel efficient as similar sized 4 strokes.<br /><br />That includes Evinrude, Yamaha and Mercury.<br /><br />Good luck. :)
 

Solittle

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Re: What HP motor for 21ft aluminum boat?

I had an 18' alumnium job with a 100 hp and the performance as fine for the wife and I and two kids. I had a 19' fiberglass job some years later with one more kid plus their friends with a 140 hp and it was a screamer. It usually would go faster than I was comfortable going in any kind of waves.
 

doclynne

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Re: What HP motor for 21ft aluminum boat?

Thanks for the input, guys. Are there any brands of motors, either in 2 stroke or 4 stroke that a person should definitely stray from, or grab up because they are the best? (150 to 225hp range)
 

JB

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Re: What HP motor for 21ft aluminum boat?

Hi, DocLynne.<br /><br />Stay away from late 90s OMC-made V6s with Ficht injection and same period Merc Optimax.<br /><br />Current models of both are good.
 

Bobby D.

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Jan 10, 2003
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Re: What HP motor for 21ft aluminum boat?

Hi doc, I have a 21' fibreglass fishing boat w/ a small cutty. I use a 1985 Johnson 140hp and with 4 fat guys I move along at about 30mph.
 
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