proper size engine?

[Cal_MI]

I have just been given a 12 ft aluminum runabout open fishing boat. Sort of a deep V hull. The boat is so old it has no capacity plate, maybe 1960 vintage. What size outboard should I put on it? I don't want to ski, just get to fishing grounds expeditiously. I have a chance to get a used 25 Merc with controls but I think that may be too much.

 

[Link]

Re: proper size engine?

Hi Cal_MI <br />Welcome to IBOATS. Yes that 25 HP would just be dangerous. I'm think something around 6-7 hp on a 12 foot would be about right. Any idea on the dry weight of the boat? This will help others give you a better idea on what size motor.<br /><br />Link

 

[Cal_MI]

Re: proper size engine?

Dry weight? When is a boat ever dry? <g> It is an aluminum shell. A simple aluminum fishing boat with two benches. Nice deep V bow for taking Lake Michigan waves IMHO. I can lift and carry it. Maybe 100 pounds? I'll get my bathroom scale out and check when it stops raining. Of course, I am adding seats, oars, an electric motor, control panel, lights, VHF radio, rod holders, flotation under the benches, anchor chocks, horn, etc.<br /><br />I see a used 12 ft boat for sale that is rated at 15 hp.

 

[RatFish]

Re: proper size engine?

I have a 12' Aluminum semi-v with a 9.9 Evinrude. Runs great with 2 adults and gear.

 

[Link]

Re: proper size engine?

Well I just had coffee with a co-worker who has a 12 foot Like RatFish just described and he also runs a 9.9 Johnson with his two kids and says it handles very well. 20 + years with same boat and motor!<br />Sounds like your going to have a blast rigging that boat! <br />I wonder what other will recommend.<br /><br />Keep us posted<br /><br />Link

 

[kd6nem]

Re: proper size engine?

I had a five horse on a twelve footer and it was unable to plane most of the time when I was alone, out of the question with a partner and a lot of gear. And I was maybe 150 lbs back then. Go with the 9.9.

 

[mulv80]

Re: proper size engine?

I had a 1973 12ft Sea Nymph that probably weighed in the area of 75lbs at best. I had a 9.5 Johnson on it and then moved to a new 9.9 Gamefisher, both motors would easily plane the boat with 2 people and gear no problem. I always wished I had a 15hp for when there were 3 people in the boat. If I were you I would look for a 15hp because it weighs the same as a 9.9 and offers a little extra push if you need it, as well as it will most likely bring a slightly higher resale value.

 

[Cal_MI]

Re: proper size engine?

According to the Coast Guard formula, (L x W x 2) -90, the maximum Hp is zero, 15, or 20, depending on how I measure the width. I think I believe the 15.

 

[Bass Runner]

Re: proper size engine?

Cal you can do this 2x thelength x the width -90=hp rating in other words 12x2=24x5(if that's the width)=120-90=30hp rating, that sound a bit much but if its a wide deep draft boat that would be about right. A good check would be to get ahold of the lake Mi. attoritys and ask them they will tell you what motor you can put on the boat. Hope this helps. My self i wouldn't got out on the big water with such a small boat, just call me chicken.

 

[Boatist]

Re: proper size engine?

Cal_MI<br />I have a 1967 14 foot aluminum Klamath car toper. Center line length about 13 and 1/2 feet. Started with a 9 1/2 Johnson. It would get you to where you were going but would not plane. In 1975 I changed to a 15 HP Johnson. With the 15 would plane with 1 or two 160 pound guys and light fishing gear. Add a third person and still would not plane. The 15 hp Johnson/Evinrude is the same weight as a 9.9. Only real difference is the carburetor. I would get a Later model 15hp that has 15 hp at the prop shaft. Engine Weight with a small aluminum boat is a big key. The 15hp Johnson/Evinrude weights 74 lbs in a short shaft. It will not be too much power for 2 or 3. On my boat with one and tiller steering the front was very light and needed to put all the gear up front. I think the 15hp is the right choice.

 

[Cal_MI]

Re: proper size engine?

Yes, Bass Runner, with a 12 foot boat you do have to choose your weather before venturing on Lake Michigan. I have been out there in 10 and 12 foot boats and was OK in a 16 ft boat in 3 foot waves. Of course, my 19 foot kayak will take all any sane person wants to try on the big lake.

 

[Bass Runner]

Re: proper size engine?

I've been out on inland lakes around here and let me tell you when you get caught out in a T-storm, and the waves start comming over the front of a 18' deep v it kind of makes your butt grab the seat.

 

[scott begovich]

Re: proper size engine?

If it has a wide beam with a good amount of freeboard, I think with gear, coolers, gas etc, you should be fine with a 25. When I was a kid we had a 10 footer(glass so heavy) with a 25 and it was'nt to fast, maybey 30. I believe a little more power will get you out of a lot more trouble than it will get you into

 

[cobra 3.0]

Re: proper size engine?

Go with the 15. I have a 15 on my 13 1/2 foot princecraft cartopper aluminum boat. Boat weight 130 lbs. It planes my boat easy with three people and is far lighter than the 20's and 25's.<br /><br />25 sounds like overkill on a 12 ft aluminum.

 

[Solittle]

Re: proper size engine?

My vote goes for 9.9 or 15 - a 25 would be overpowered.