Minor porpoise issue

[Kevin23]

You just need a different prop is all. Hit the mercury prop selector tool and put in all of your information and it will tell you the recommended prop. Try that prop and then go from there.

You might lose a MPH or two but whats more important here? Performance or top speed bragging rights?

[wellpastcold]

Originally Posted by Black98TransAM

Would a hydrofoil help? The foil would be out of the water at wot and that's where I am getting the porpoising.

Alan I will not take a chisel or anything to my boat. I have a suspicion I can raise the motor up one more hole and I'm looking at a spitfire x7 prop (propman recommended this). I really don't think I would go the trim tab route not sure it's worth the cost and I think I can get this figured out.

I do think I need more bow lift and that is part of my problem. The spray exits the hull right where I sit at the console.

According to the manufacturer it will eliminate porpoising. I can't say for sure as I have not ever owned a boat that had that issue.

[REW]

Black,
Find a 17 pitch prop with a high rake angle and see how that goes.

The 17 pitch prop will be a better match for the power of the motor and size of the boat.

The high rake angle will really help to lift the bow of the boat and minimize porpoising.

Take care

[Fenwick]

Originally Posted by Black98TransAM

Boat: 1998 Alumacraft Tournament Pro 170cs

Motor: 1998 Mercury 90hp ELPTO mounted in 2nd hole from the top

Prop: 19P Michigan Wheel vortex 3 blade aluminum prop.

Loadout. Terrova 80 on bow, 2 series 27 deep cycles on bow, series 27 cranking battery on stern, tackle boxes on stern.

The boat will propoise at the top of the RPM range. I can trim down and it corrects it but I lose speed and can tell I'm plowing water a bit more. The prop does not blow out when trimmed to the point the porpoise starts. If I fill the front livewell and leave the rear empty it comes pretty close to fixing the issues but it still seems like I need some more bow lift as the spray is exiting the hull right where the console is.

Thoughts as to what I could try to fix it? Move the motor up? Prop with more lift? etc?

Easy fix. Find the sweet spot and give up a few MPH. I rarely go WOT on the Great Lakes. Can't without beating the boat and passengers. I had to add a foil to my 2000 Lund Tyee 1950 as it was a$$ end heavy. Just the nature of the beast. Tried a lot of props and settled on a High Five. This boat I'm running a Solas 4 blade 13.75 19 P. Great hole shot and without maxing out rpm I get 39 on a calm day. Most days I'm just hitting 20 mph.