2018 Triton 17 tx set up help needed

[518svx]

I bought my first aluminum bass boat after owning 3 fiberglass ones. I am having a porposing issue with it and was looking for some help with it. It's starts proposing at 37 mph @5k rpm.

Motor is a 75 Mercury 4 stroke
18 pitch Mercury Vengeance 3 blade prop
Motor is mounted in its lowest position.
It was previously one hole up from lowest but was moved down by the dealership trying to resolve this issue. This did nothing to change the issue, same problem, same speed at the same rpm


Is this just the nature of a shorter aluminum boat or is something not right? I know this motor maxs out at around 6k, so I know there is theoretically more than I can get out of it. Hole shot is fine, drives well, no issues except for this one.

Thanks in advance.

[GeauxTide]

Ah, yes. The porping issue. 1st. Move your motor up to hole #2. 2nd. Be sure you should have a wedge welded to the bottom on each side at the transom. 3rd. If 1 and 2 don't help, Spitfire X7 17" prop. With a Spitfire, you can go to Hole #3. I have a Laser2 20" and an X7. The Laser is faster, but the X7 carries the boat like a dream!

[Casslaw]

I have an SP185 that actually thinks it’s a porpoise! Getting a good prop def helped but my p2p is still in the 5.5” range so I have to move the motor up! I’m going to go all the way up, it’s on the 2nd of 4 holes now. I’d love to get a 4” manual jackplate but I can’t just yet.

I got a powertech nrs3 and that helped me a lot. My boat is super weight conscious! By myself with a full tank I rarely porpoise, but loaded down with another person and full tackle it likes to bounce! Play with weight distribution first!

[fishon396]

I have a rt178 with a 75hp and the motor came mounted in the second hole from the top. The boats do seem trim sensitive and seem to need very little trim, I carry a heavy load and the boat seems to run best between 1/4 and 1/2 trim and my max speed has been around 38 and with the stock tach around 5400 rpm. I do have the 17p Spitfire X7 prop and that helped some with the handling and porposing. in my case I don't think there is much more speed I can get with my setup.

[518svx]

Thanks for all of the replies. I may just live with it. I can't see where getting into a new prop and all of that is really going to make that much of a difference. I'm good with 37!

[alanhore]

Move the motor to the third hole. You are too deep.

[518svx]

I was wondering this when they said they were dropping the motor. I always thought going up would help it. I may take it by and get them to do it but I'm tired of driving to the dealership.

[Casslaw]

Get a friend with a GoPro, or buy one, and load the boat like normal and see where your cavataion plate is when you’re at full throttle..I’ll bet you won’t be able to see it! I did this and my cav plate isn’t visible when I’m on plane at wot, so the motor has to come up!

A good, stern lifting SS prop will help a LOT with handling, staying on plane at lower speeds, etc. Made my boat 100% different but I won’t see the full benefit until my motor is in the right spot...and it’s not.

My boat goes 40-41 but it’s not about speed, although it may pick up 1-3mph, it’s being able to use the trim to help drive the boat!

my boat is limited right now because my motor is too low, period.

[tjsellsfords]

I have a 18'5" Crestliner VT 18 with a 115 on it and I was getting bad porpoising in the 2nd hole at 39-40 mph, moved up to the 4th and now don't get porpoising until around 45-47. I plan to change out props when I have some extra cash.

[Casslaw]

TJ, what’s your p2p? On mine I can raise the motor 1&3/4” which would put me about 4.25p2p...I’m sure it will help but having a 4”jackplate would just be so much easier! If I’m raising the motor I’m going all the way up since I’d still be at 4.25 p2p.

When you raised your motor did you get more useable trim?

[518svx]

Get a friend with a GoPro, or buy one, and load the boat like normal and see where your cavataion plate is when you’re at full throttle..I’ll bet you won’t be able to see it! I did this and my cav plate isn’t visible when I’m on plane at wot, so the motor has to come up!

A good, stern lifting SS prop will help a LOT with handling, staying on plane at lower speeds, etc. Made my boat 100% different but I won’t see the full benefit until my motor is in the right spot...and it’s not.

My boat goes 40-41 but it’s not about speed, although it may pick up 1-3mph, it’s being able to use the trim to help drive the boat!

my boat is limited right now because my motor is too low, period.

I have been looking at Powertech props. I will probably stop by and get their advice since I work not too far from their shop. It definitely sounds like it needs to come up 3 holes from where it is now. Thanks for all of the help.

[GeauxTide]

Powertech are good folks.

[Casslaw]

PowerTech are good folks, they are VERY good at picking the right prop the first time and will swap it out for $30 if you don’t like it...much easier to get a good prop when you can try different ones and have experienced people helping you! Good luck!