My new boat has a tendency to porpoise at medium to low speeds, although does go away when I trim down further, but feel that riding the way is not optimal as too much of the hull is in the water.  I have repositioned batteries & fuel tanks and have been able to minimise the effect, however I do not want to just accept the porpoising because it's a bass boat.  

I wanted to know the following:

- Will installing a hydrofoil limit the porpoising?

- Will installing a jack plate compound the problem

Loosing a couple of mph is not a big issue as I am after ride comfort.

Boat details - 16ft, +- 1600lb's, Merc 115

Smart tabs would be the ideal solution but the cost ($ 150 vs $ 50 for a hydrofoil) is an issue.

Tx in advance.

You don't say whether your boat is glass or aluminum but my response applies to glass.

I have had two bass boats and they both would porpoise if you were trimmed out to far for the speed you were running. IMHO it is a fact of life that if you are porposing you either tuck the motor under a bit until it stops or increase the throttle a bit until it stops.

If you have the boat up on its pad, properly trimmed out for speed, load, motor and hull I think trim tabs are unnecessary. If your boat was prerigged I think moving the batteries and fuel tank might have been a mistake.

My "Leading Edge" trim tab was just to improve hole shot which it did and I don't think adding a jack plate is your answer although it might help overall performance.

I went from several smaller motor, fishing boats to bass boat 1 with a 115 Merc and it took a while to learn to drive it then bass boat 2 with a 150 Merc took even longer to learn to drive it comfortably and efficiently.

At what point are you suffering the porpoising?

I had a 16 1/2 Champion that did that but only in the 3200-3800 rpm cruising range.  Beyond that it ran fine.   The hulls were known for doing that due to the Extreme weight in the back end of the boat.  I just trimmed in and dealt with it that way.  It added more steering torque while cruising but it wasn't objectionable.

Yes I have a 16' that is doing the same thing. No a jack plate doesnt eliminate the issue cause the boat has a jack plate. But the fin will help eliminate it . The issue is the boat is short and will do it unless its fully timed down. The foil will also help out planning time and gas milage. I am getting one for this boat this weekend. I have used it on other boats with great results.

Short answer: yes they help eliminate porpoising.

However like others have stated, there are other variables in this equation as well.

ok short boats will do that until the trim is just right. You got to play with the trim that all.

once your on your pad you will know it. the steering tork will not be fighting you and the boat will not porpois. the boat is not under powered so maybe you can try a whale tail but it will cut in to the turning of the boat.

Take some pictures of your hull and engine trimed down, and one of the lower unit that would help a bunch. There may be a set up problem. Oh pictures at different angles.

Also get an experienced boat driver to go out with you it could just be learning some boat driving skills.

Hell call me up i will go out with and will have you dancing across the water with her.  

I have one a SE 300 on Tracker Targa 17SC with a 90 Merc. glad I did. I'd put one on yours if I were you.

Hi Guys,

Thanks for the input so far.  I installed a hydrofoil last week end and to be honest, only a little improvement was evident.  Am considering trim tab option but will have to see if I can import from the states as they are not available locally.

Oh by the way,

FOR SALE/TO SWOP

x1 wife, 1974 model, wide body, great washer and ironer, reasonable mileage for $ 150-00 or to swop for set of trim tabs. ;D