Fin or no?

[BeeEl]

Hello, let me start by saying I have searched the forums first, but got no results. I probably am using the wrong terminology. Anyway, when I got my boat it had a busted lower unit. I have since replaced it and fixed various issues. Everything seems to be running fine now. the boat seems to "stand up" for a bit before it planes out. I have played with the trim, but the issue still remains. I still have the busted lower unit and noticed the previous owner had installed a hydra fin (or whatever it's called). I understand that these are supposed to greatly help this problem. Before I drill holes in my new lower unit, I wanted to ask you experts' opinion. Should I? I am just not sure if they are a good thing or if they just cause other problems or issues.

Thank you in advance.
BL

 

[Fishermark]

Re: Fin or no?

I understand that these are supposed to greatly help this problem.

Key word there: Supposed to help. They do not. If you have continuing problems, you might try trim tabs. Otherwise, shift the weight to the front of the boat.

 

[ziggy]

Re: Fin or no?

when going from plowing to plane, have your trim all the way in, down. after your on plane, then trim out to max rpm w/o changing throttle position.

the stress with a whale tail is put back onto the gimble housing to force the bow down.

fm has the right idea. smart tabs or real trim tabs is the way to go.

oh, i had a wale tale on my last boat, all it did for me was break off a piece of my anti cavitation plate when i hit something on the river.

 

[dubs283]

Re: Fin or no?

no manufacturer recommends intalling anything like that on a drive, they do more harm than good

 

[alldodge]

Re: Fin or no?

Hello, let me start by saying I have searched the forums first, but got no results. I probably am using the wrong terminology. Anyway, when I got my boat it had a busted lower unit. I have since replaced it and fixed various issues. Everything seems to be running fine now. the boat seems to "stand up" for a bit before it planes out. I have played with the trim, but the issue still remains. I still have the busted lower unit and noticed the previous owner had installed a hydra fin (or whatever it's called). I understand that these are supposed to greatly help this problem. Before I drill holes in my new lower unit, I wanted to ask you experts' opinion. Should I? I am just not sure if they are a good thing or if they just cause other problems or issues.

Thank you in advance.
BL

Not going to get into the hole dolefin, whale tail, stringray etc thing. When your drive is all the way down, is it parallel to the transom, or is it a bit more in or out? Not talking about if it is straight up and down, but does it match the transom line?

 

[BeeEl]

Re: Fin or no?

I'm not sure what line it is on. I've never checked it, but I can.
It sounds like the fin is not the way to go. Glad I asked. I can trim it down while plowing. That's easy enough. I'm not sure trim tabs are in the budget right now.

 

[stonyloam]

Re: Fin or no?

Every boat is different, I have a plate on mine, and I think it helps. Like Alldodge says, take your boat out and see how it responds to the trim. Trim flat to start then as it comes on plane try to find an optimum. Once you know how your boat responds to trim you can decide if it needs more help.

 

[alldodge]

Re: Fin or no?

I'm not sure what line it is on. I've never checked it, but I can.
It sounds like the fin is not the way to go. Glad I asked. I can trim it down while plowing. That's easy enough. I'm not sure trim tabs are in the budget right now.

My questions are to determine if the drive is not going under the boat enough to be able to lift it up on plane correctly (maybe the trim cylinders were replaced with ones which are to long).

Maybe something else with the setup is incorrect by PO. Is WOT correct (propeller pitch, drive ratio, weak engine, other stuff).

 

[stonyloam]

Re: Fin or no?

Remember everything affects the trim. Speed, wind, waves, number of people and where they sit, so you need to be constantly changing the trim for the best ride. Watch your tach, small trim changes will result in changes in engine RPM, look for a point of maximum RPM at a given throttle setting. I never look at my trim gauge, don't even know if it works, usually just trim up till it just starts to, porpoise then back off from there for the best ride and max RPM. if you are tubing or skiing try to get the weight up forward. Go have som fun.

 

[Starcraft5834]

Re: Fin or no?

if your boat is plowing and taking to long to plane,, lots of possible reasons.. wrong prop for load. engine power, heavy soggy boat.. trim or whale tail help not going to fix that... make sure your engine's sound first, if so,, look for proper prop,, perhaps a 4 blade in optimal pitch...

 

[MikDee]

Re: Fin or no?

I'm a Doel fin fan!

All the other fins seem too big, bulky, & funky.

I've had good results on boats that needed them, some boats don't.

They've worked for me on boats that struggle a bit to get on plane.

 

[ouachitaman]

Just say no to fins. If you need more low end grunt, go down prop pitch sizes. Just check your rpm at wot.

 

[JimS123]

The Doelfin is the best thing since sliced bread. They do all they claim and more. Get your prop optimized and then bolt one on and get the best of both worlds. If they were no good they wouldn't have been selling like hotcakes for 30+ years, and you wouldn't see one on every 3rd boat (at least in my neighborhood).