What size engine to plane a 12' Aluminum?

Discussion in 'Saltwater' started by sinc, Aug 11, 2007.

  1. sinc New Member

    Posts: 2
    Victoria, B.C.
    Ratings: +0 / 0
    I'm wondering if anyone can tell me if an 8HP 2 stroke would be enough to get my 12' Aluminum up on plane (2 guys on board). It's an old Sears boat that probably weighs around 150lbs.

    I had an older 9.5HP Evinrude that got it up on plane pretty easily with some gear and 2 guys on board. That motor has since died and I'm trying to decide between a Yamaha 9.9 HP 2 stroke or Yamaha 8 HP 2 stroke. I know the 9.9 will get the boat up on plane easily but it is quite heavy (79 lbs), the 8 HP is relatively light at 60 lbs. Since I'll likely be carrying around the motor quite a bit I would prefer a lighter one but not if it won't get the boat up on plane. Thanks in advance.
  2. Benn Member

    Posts: 144
    Ratings: +8 / 0
    I have an older (mid 80's) 8 hp merc that I used to use on an old heavy 14' 1950's vintage alum rowboat. The motor would plane one guy OK with gear (including a electric trolling motor and a battery). It would not plane with two guys well, so I put on one of those stingray stabilizers and it really made a difference. It cost about $50 and went on in about 10 minutes. It really popped up great with one person and it got on plain fine with two (both 225+ lbs) plus gear. It also makes it the engine easier to deal with since it will act like tripod and hold the motor with the handle side up when you lay it on the dock or back of the truck.

    That said, if cost is not the main issue, I'd get the larger engine. It is always good to have something in reserve and the few extra pounds at the stern won't make much difference. I'd bet that if you can lift the 60# OK, the 79# should not be too bad, but then again I don't have to carry it.
  3. sinc New Member

    Posts: 2
    Victoria, B.C.
    Ratings: +0 / 0
    Thanks for the info!
  4. Clint F Fly Fishing Youth

    Posts: 675
    Port Orchard,WA
    Ratings: +3 / 0
    I have a 12 foot gregor that has a 15 hp outboard. It can do 23 mph with my dad, me, battery, 6 gallons of gas,and gear. I hope this info helps you make your motor selection. With that said I would go with the 9.9

  5. gt Active Member

    Posts: 2,616
    sequim, WA
    Ratings: +6 / 0
    so where do you intend to run??? if taking the motor on and off is really an important consideration, than i would think the less weight the better, unless yur one strong dude. a tenhorse should be plenty.
  6. Matthew Gulbranson Resident Swinger

    Posts: 1,733
    Seattle, WA
    Ratings: +47 / 0
    Although the 9.9hp 4 stroke is going to be heavier than the 8hp, my vote is definetly for the 9.9. I just recently purchased a 9.9 2 stroke for my 12ft alum. and it planes very nicely. Since it is a 2 stroke it's lighter than a 4, it is easier to carry, but I would go for the 4 stroke if I could afford it.
  7. Nutty Squirrel Says: Smoke Salmon not Crack

    Posts: 49
    Ballard, Wa
    Ratings: +0 / 0
    I used to own a 12' SmokerCraft Alaskan with a 9.9 Evinrude and seem to remember being able to go about 16-17 miles per hour and got up on plane without a problem w/two people & gear. I did have one on those whale tails mounted on the shaft of the 9.9 and that really seemed to help get the boat on plane quickly.
  8. Denny Active Member

    Posts: 4,043
    Seattle, WA, USA.
    Ratings: +45 / 0
    It depends very much on your boat. What is its horsepower rating?

    If you're carrying around the motor, it sounds like it's a pretty light/shallow boat. If fcarrying it, the 8 hp; if you trailer the boat, I'd be all over a 9.9, and a 15 would be preferable.

    Again, it depends on the boat rating.
  9. Couleeflyfisher Member

    Posts: 398
    Ratings: +5 / 0
    Most 9.9 hp motors are same head as the 15's. The 8 hp's are usually same as 6 hp block and quite a bit less motor. To plane a 12' I would definitely go the 9.9, and 2 stroke is a lot lighter motor than 4 stroke. My 15 hp Merc 2 stroke would push my 13' Fisher 23-24 mph with 2 aboard, 9.9 should easily plane your boat.