Welcome Guest - Sign Up today
Welcome Guest - Sign Up today


No announcement yet.

Whale Tail

  • Filter
  • Time
  • Show
Clear All
new posts

  • Whale Tail

    I have a 1985 Bayliner 17 foot trophy bass boat with a 1985 force 85. The Previous owner installed a whale tail on the motor. I have had various results using Dolfins on I/O's in the past and am wondering if this whale tail is a benefit or not. I'll probably remove it and do a test but before I do I thought I'd see what the experts think. I currently run with the motor angle pin in the first hole closest to the transom. If I move it back even one hole the bow continually goes up and down. .......And what should I expect for top speed? I currently have a 21 pitch prop and get about 30-32 with just me in the boat...........Thanks in advance for any input........John

  • #2
    Re: Whale Tail

    I know your looking for experts for comments, but you'll have to do with me for now. I have a 17' Bayliner bowrider w/85HP Force. I also have the Fin on the motor. I thought they came from the factory with them because everyone I saw like mine has one on. Anyway, I don't know what the pitch of my prop is, but it's S.S.. With just me in the boat at WOT I'm running at 34-35 mph (GPS) @ 5200 rpm. I run the trim pin in the same hole as your using, lowest hole. I've asked the same question about the Fin & got the same basic answer from everyone: Take it off & see how it runs, if it's better leave it off, if it's worse put it back on. I never took mine off to test it both ways because, every chance I get to take the boat out I don't want to screw around taking it off & testing it. I feel it runs just fine for me, ya, I'd like to get the speed up a bit & that has to be causing quite a drag in the water. Maybe next time I'll have time to test it out without the fin. Do you have a tach? Sooner or later some one with some real knowledge can give you more information. Just wanted to let you know that yours seems to be as good as mine & I have no issues. Post up a picture of it when you get a chance.
    No Matter where you go.......There you are.


    • #3
      Re: Whale Tail

      Thanks for the info MAXXIE.......no one else responded so you are the expert. I'll put it off (only 6 bolts) and see what happens......thanks again1......John


      • #4
        Re: Whale Tail

        A dolefin with a 21p prop sounds like you need help.Take it off.Hook up a tach and go for a ride.
        I bet the 21p prop won't let the motor rev past 4500.
        That boat came with a 17 or 19p prop.
        You need to watch the load.Cooler full of beer,dog,2-3 kids,2-3 adults,full tank of gas.Too much.
        1-2 adult or 1 adult, 2 kids 1/2 tank of gas.Then go for a ride.
        You should tach out about 54-5500rpm.
        The trim pin should be in the bottom or second hole.Get a trim and tilt if possible.That would make a world of difference.
        Post your results.J

        Buy American made Cars and Trucks!!!Towing insurance for a boat,a GREAT thing.
        ​Tools to make my life easier: Battery tester, die grinder, temp.gun, compression tester, DVA meter.

        In Scenic , Beautiful San Sebastian by the sea Florida

        88 Bayliner 21CC 2001 Mercury 225 HP EFI



        • #5
          Sign up today
          Re: Whale Tail

          Thanks jerryjerry05....i'll pull it off and see what happen. I also have a 19 pitch prop that is damaged, maybe I'll look at fixing/replacing it. It might be a week or two before i can take off the whale tale..........i don't have a tach but i will post results.......Thanks again.........John