Whale Tail

jddens

Seaman
Joined
Aug 30, 2007
Messages
62
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
 

MAXXIE

Chief Petty Officer
Joined
Feb 26, 2009
Messages
556
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.
 

jddens

Seaman
Joined
Aug 30, 2007
Messages
62
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
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
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
 

jddens

Seaman
Joined
Aug 30, 2007
Messages
62
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
 
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