Dolfin

[Fireguy]

Do the Dolefin units help with getting on plane at lower speeds? If these are so great why arn't motors built with them already designed in, is there a downside to using them?

[Cliff Wagenbach]

I had a Sting Ray hydrofoil put on my 115 Yamaha and it helped greatly to get me on plane faster! There was no noticable difference in steering or speed reduction.

Cliff

[Jeff S]

Fireguy,

I had one on a used boat I had bought. I would not recommend one if you fish rough water alot. I fish Mille Lacs quite often in some very rough water. The problem I had was the plate the dolefin was mounted too broke due to the extra stress put on it when the boat dropped into the trough of a wave. I saw no noticabe difference in performance while it was on the boat and did not miss it after it was taken off.

Hope this helps,

[marine_man]

In my unprofessional opinion hydrafoils, whale tales, dolfins, etc are a band-aid for another problem... typically a prop that is not sized appropriately for the boat / motor combination. Especially for the typical MN sized boat. Larger boats (lake superior cabin cruisers, yahts, etc) use trim tabs to help get them up on plane given their large size and weight... but I don't think we're talking about that size of boat here.

Yes, they do help.. but I think there are better ways to get on plane quicker or get a better holeshot.

marine_man

[ccarlson]

I agree that they may not help get on plane faster but there are cases where the fin can help a boat.

I've had some boats that I've tried them on to no advantage.

The boat I have right now though, benefits greatly from a fin. The benefits I see are being able to stay on plane at a much lower speed than without a fin (great for tubing with kids) and reduced porpoising. I have a Ranger 690 C with a 150. This ranger was known for wanting to porpoise at slow to mid range speeds regardless of prop and rigging. The fin greatly helps and allows me to trim up a little at slower speeds to run the motor in a more efficient RPM range.

The post about the cavitation plate absorbing the shock of the fin in rough water is right on though. I did have a double layer of cavitation plate added to my motor so it would not crack from the added pressure in rough water. This cost me about $90 at a prop shop to have done.

The benefits that I note from using a fin on this boat could be better accomplished from the use of trim tabs but fishing boats are not suited well for them with all the transducers and trolling motors etc. we have on the back of the boat.

Each boat is different and some may see a great benefit from using a fin. I know I did.

ccarlson

[Wish-I-Were-Fishn]

I have a Sting Ray on my Merc classic 50. It works well. I got it because it's a tiller motor and with all the weight in the back of the boat (when fishing alone) I had trouble getting on plane at lower speeds. It works good for me.