TR-18 porpoising

[bornforit]

I need some help.

My dad bought a bought used and it doesn't sound like its setup right nor will he listen.

Its a 2010 Tr-18 with a Optimax 150 on it. Has a Tempest 21 pitch prop.

Problem

He lives on a stumpy lake and cant really ever open it up. On the boat road he runs about 30 mph. Problem is you feel like your riding on a dolphin. I was thinking the prop is the issue and needed a 23. Anyone confirm the prop and any other info.

Thanks

[Triton150]

I'm no expert, but seems to me he's trimming up too much for his speed/prop. Either increase speed or trim down the engine. I have Tr-186 with a Opti 150 and a 23p prop is the right prop for my boat.

[Flatline]

More info is needed. How is he getting on plane, trim settings

might want to look into a hydrofoil if your needing to be in plane at a slower speed

[berudd]

I'm no expert, but seems to me he's trimming up too much for his speed/prop. Either increase speed or trim down the engine. I have Tr-186 with a Opti 150 and a 23p prop is the right prop for my boat.

That's what I am thinking too. He will not be able to run 30 MPH with the motor trimmed up to high. He'll need to trim down to eliminate the porpoising at this speed. And that would be independent of what prop he has on.

[ROADRUNNER]

You have to find the sweet spot between Speed ( RPMs ) and trim. Try trimming it all the way in ( down ), open it up until you get on plane, then trim it up gradually ( as speed increases and are on plane, you can throttle back a bit ). You will find a sweet spot.

[Bob McKenzie]

too much trim and not enough speed will cause exactly what your describing, you could go to a 23P on the opti but from what I'm understanding is that your dad keeps it trimmed up to avoid stumps, truth is he's only buying himself mere inches if that of clearance, and if the boat is bouncing that bad he might not be gaining any clearance. He should invest in a Hydraulic jack plate for better clearance and trim down to eliminate the bounce. A 21 will be more likely to keep the bow high with all that bite.

[bornforit]

Sorry. more explanation.

Getting on pad with trim all the way down. At that point running 30 mph and running with the boat still trimmed down its porpoises. Trimming up only makes it worse.

Through the comments above I think I got it figured out. I put my tempest 23p and my trophy 24 on it. At this point its a lot better. I also figured out the motor is too low. No wonder the guy sold the boat, he had no idea what he was doing.

[ROADRUNNER]

Well raise the motor, as I don't think the different props would help that much if at all. Good Luck with your boat.

[Fishysam]

I was able to run my boat at 17.5 on plane without proposing, I raised my motor up some after break in it would porpose at 27, I went back down almost to stock height and I plane at 19 now, depending on load. So I would start with lowering the motor. Then move more weight forward. If all the heavy stuff and or 3 people are on seats you need more speed, if the third person sits on the cooler it helps a lot for slow speed driving.

on my boat the jack plate is only up about 3/8ths from flush on top the p2p is burried deep.

[JJolley]

Had a 186 with 23p Tempest it could plane out and cruise at 20mph with no problems, p2p was 2.75" of course you have to make sure the load in the boat is balanced.