12 ft aluminum boat max hp

kdc2000

Cadet
Joined
Nov 24, 2002
Messages
20
I have an aluminum boat with a 17" transon, 18" deep, 56" beam, 11'6" long. What would be the upper limit for hp in a boat this size?
 

fire831

Petty Officer 1st Class
Joined
Aug 26, 2002
Messages
373
Re: 12 ft aluminum boat max hp

I have a 12 ft. v-bottom and my tag on the hull says 7 1/2 h.p. max. Hope this helps.
 

Mumblerone

Petty Officer 1st Class
Joined
May 12, 2002
Messages
344
Re: 12 ft aluminum boat max hp

I'd stay with 6-8 HP...the larger motors start to get a little heavy. You'ld be OK with a 4-5 also. ;)
 

11 footer

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Nov 16, 2002
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1,408
Re: 12 ft aluminum boat max hp

I have an 8hp short shaft for sale that would work good with that boat. You could keep that in mind.<br /><br />11
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: 12 ft aluminum boat max hp

Ahoy, KDC.<br /><br />I agree. I never saw a 12' "tinny" rated for even 10hp.<br /><br />Good luck.
 

Tacklewasher

Lieutenant Commander
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Sep 18, 2002
Messages
1,588
Re: 12 ft aluminum boat max hp

My dad has one. Rated for 15hp. When he stops fishing, I've laid claim to it as it is a nice, wide, heavy 12 footer that is much more stable than mine. Just a bit heavier so I might have to steal his boat loader as well.<br /><br />Mine's rated for 10 and I have a 9.9 Johnson on it. Usually just use the 30lb MinnKota though.
 

Luna Sea

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May 20, 2002
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1,070
Re: 12 ft aluminum boat max hp

For Ryan T.<br /><br />How much for the 8 horse?<br />email: mtowey@analogic.com<br /><br />Luna Sea<br />Beverly, Mass
 

Jack Shellac

Lieutenant Commander
Joined
Aug 7, 2002
Messages
1,661
Re: 12 ft aluminum boat max hp

The answers are right about keeping the horsepower down. I stuck a 25HP Evinrude on my 12' aluminum boat one time just for the heck of it and I don't think there was anything in the water but the propellor. Extremely squirrely handling and scary. Came back slowly and carefully.
 

Chum Slick

Petty Officer 2nd Class
Joined
Aug 7, 2001
Messages
116
Re: 12 ft aluminum boat max hp

Depends on boat manufacture. 12' Sea Nymph with 20 hp Suzuki...She'll scream but she's definitely not for everyone. I scared the bageezers out of a friend of mine in it. I have a good friend with a 12' John boat with a 130 hp Allison R/R. Got a really big prop that sits about 4 feet above the water.
 

bKelly

Petty Officer 2nd Class
Joined
Jul 1, 2002
Messages
191
Re: 12 ft aluminum boat max hp

There is a game warden here that has a 12’ war eagle with 25hp mercury. It handles well and rides good. I thought it would be overpowered but it was not.
 

whfmznb

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Joined
Nov 6, 2002
Messages
27
Re: 12 ft aluminum boat max hp

I have a Sea Nymph 14R, max rated for a 25hp.<br />I am not a "speed deamon" but would like to get up on a plane.(I am running a 4hp :( Yamaha).<br />I am seriously lookig at a Tohatsu/Nissan but the 25hp is a three cylinder and is quite a lot of motor for a 14' aluminum. Would the 18hp <br />move get the boat up?
 

Big Al1

Seaman
Joined
Dec 8, 2002
Messages
68
Re: 12 ft aluminum boat max hp

I've got an old Merc 60 (6hp). It does alright on my 14ft jon boat. Mine is about 4ft wide and about 3ft wide at the bottom. It actually rides better with two people in the boat. The extra weight up front evens the weight out and the boats rides flatter and faster. With just me in the boat (140lb), the boat will do 15mph on a glass surface. Rough water slows it to 12mph. I feel that a 9.9 is what I really should have but the 6 does the job.
 

11 footer

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Nov 16, 2002
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1,408
Re: 12 ft aluminum boat max hp

Big Al,<br />If your gas line is not to short you should try puting the gas tank tord the bow. I do it with my 11' whaler with a 15hp merc and it will plane faster and get a little more top end. When there is only one person in the boat.<br /><br />11
 

Big Al1

Seaman
Joined
Dec 8, 2002
Messages
68
Re: 12 ft aluminum boat max hp

Ryan, <br />Well I have a one gallon tank that I converted into a outboard gas tank. I just drilled a hole into the cap and hot glued the nozzle in place. One gallon is not much weight. I keep a two gallon on reserve in the very front though. You did make me realize that I should move my trolling motor battery to the front on the boat. But I'll still need the terminal posts at the back for the trolling motor. I guess I could run some heavy gauge wire to the back and screw on some posts.
 

11 footer

Lieutenant
Joined
Nov 16, 2002
Messages
1,408
Re: 12 ft aluminum boat max hp

My boat is remote stearing and I have neaver done this before but I have seen tiller extensions when you can make them real long and sit on the bow yourself. That might help.<br /><br />11
 

CalicoKid

Lieutenant Commander
Joined
May 27, 2002
Messages
1,599
Re: 12 ft aluminum boat max hp

Here is a pamphlet in PDF form by th US Coast Guard reguarding Safety Standards for Backyard Boat Builders which contains a wealth of information and tests for building/modifying boats and will surely help you answer your question. I used these guidilines to help me make the same determination about a little boat I have without a C.G. plate. By the way the C.G. plate is not federal law, but may be enforced locally! Read this USCG page first topic. I hope this helps, I got this info from another great member of this board! :D
 

NathanY

Commander
Joined
Mar 16, 2002
Messages
2,408
Re: 12 ft aluminum boat max hp

I have a 14 ft Richline ( very old boat 1965 model) and I put a 20hp Merc on it. I had a 15 on it and did not get the front up out of the water enough, got to wet all the time. Does not do that anymore though! It will run about 30 now which is entirely too fast! Only run about half throttle. All I can tell you is BE CAREFUL. I dont care what anyone says, overpowering a little boat by 5 hp is far more dangerous that overpowering a bass boat by 20 hp. I would not go bigger than a 9.9, although most popular makes ust the same engine for the 15.
 

John Carpenter

Petty Officer 1st Class
Joined
Nov 1, 2002
Messages
336
Re: 12 ft aluminum boat max hp

I have the same boat with a 9.9 Johnson & my kids have a ball with it. I would not want any more motor as long as they are running it ;) Of course, 16 yr old boys only have one speed eh?
 

FlyBoyMark

Ensign
Joined
Apr 14, 2002
Messages
934
Re: 12 ft aluminum boat max hp

My son has a 12' SeaNymph with one of the newer Force 15 hp on it...does 25 MPH with my 225 lb butt and his 110 lb butt, battery trolling motor and gear. Me alone....30-32 MPH...Force 15 is rated one of the fastest 15's around.....The performance is "comfortable" with a 15, I immagine it would be very sluggish with a 10 hp. Load has a great deal to do with performance and the construction of the transom with how much power it can take (i.e. 14 foot version of same hull that is identicle except for more length IS rated for a 15 HP)......tread carefully.....adjust the HP to your specific needs within reason.
 
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