22ft bay boat issues

[swampboy]

We have a 22ft seafox with a f250 Yama..having trouble with porpoising ..at 35 mph... We do have trim tabs ,but to my understanding it's an accessory to a boat to use for leveling an to keep your bow down on rough water.... I've heard an read that Yamaha changed their negative trim to 3 degrees..So We thinking of adding wedges to increase the negative trim... any advice would be greatly appreciated or any of you have the same boat or the same issue..

Thanks for y'all's time!!

[marty f]

Mine will do that sometimes if I have to much trim up haulin azz, so I drop the trim down lowering the bow until it stops and raise it back up to the sweet spot

[swampboy]

At 30 to 35 trimmed all the way down it does it

[marty f]

Originally Posted by swampboy

At 30 to 35 trimmed all the way down it does it

that's crazy, every boat Ive had if I trim it all they way down it just plows threw, like a bulldozer.

Has it always done this?

[swampboy]

Originally Posted by marty f

that's crazy, every boat Ive had if I trim it all they way down it just plows threw, like a bulldozer.

Has it always done this?

yes when we first got it we didn't have any tabs we couldn't go past 27mph cause of bouncing....so we brought it in an they put the tabs.. it does solve the problem,,but that's like just a bandaid on the wound.. its still there! I shouldn't have to use tabs in a smooth bayou or rivier cruising at 35mph...to me when u porpusing the first thing u do is trim down just a tad bit an it goes away! in my case I cant go down any more so I think adding 5 more degrees it should help if not solve my problem.. its just to get the dealer to add the wedges....its under warranty so they should fix my boat!!

[redaddiction]

Originally Posted by swampboy

At 30 to 35 trimmed all the way down it does it

I think that means it needs to come down some on the transom.

[meaux fishing]

Sounds like your motor may be mounted too high?

[wishin i was fishin]

Originally Posted by meaux fishing

Sounds like your motor may be mounted too high?

true dat Meaux. i lowered my engine and got alot more low range out of the trim.

[RichWentFishing504]

ImageUploadedByTapatalk1425441188.925555.jpgi can't seem to find the best picture right now but I'll use this one to explain about motor height.

Do you see the anti ventilation plate on these motors? You want it just high enough to where the plate is getting splashed just like these outboards are getting splashed.

Take a pic of your outboard when your running on plane.

[RichWentFishing504]

Btw, I do agree that something is off. A brand new boat shouldn't have these issues.

I had similar problems in another boat and had to add wedges. However you end up continuously running trimmed all the way down or just a few bumps away because the wedges don't really give a lot more range.

[meaux fishing]

Is your cavitation plate just about even with your keel?

[swampboy]

Originally Posted by meaux fishing

Is your cavitation plate just about even with your keel?

Yes sir it's pretty even..

[meaux fishing]

When you take off from a stop does your bow raise up pretty high then take 10-15 seconds to level off? If this is the case your motor could be too low

[kb7722]

Originally Posted by meaux fishing

When you take off from a stop does your bow raise up pretty high then take 10-15 seconds to level off? If this is the case your motor could be too low

Meaux is right. Motor too low can cause this issue. Have someone drive while your on plan and look how the motor is riding in the water. Is the cavitation plate completely submerged? If so your motor is too low. Measuring cavitation plate height relative to keel is just a rule of thumb. You need to see how the motor is riding when on plane.

http://www.propgods.com/forum/Default.aspx?g=posts&t=98


Also your prop could be adding to the problem. Some types of props are "bow lifting". This could be the problem or add to the problem.

[juicegoose]

Originally Posted by kb7722

Meaux is right. Motor too low can cause this issue. Have someone drive while your on plan and look how the motor is riding in the water. Is the cavitation plate completely submerged? If so your motor is too low. Measuring cavitation plate height relative to keel is just a rule of thumb. You need to see how the motor is riding when on plane.

http://www.propgods.com/forum/Default.aspx?g=posts&t=98


Also your prop could be adding to the problem. Some types of props are "bow lifting". This could be the problem or add to the problem.

Yup my 21' nautic star was having some issues with porpoising. I had installed a mercury rev4 prop not knowing it was more of a bow lifter. Switched over to the turbo and it acts like a different boat.

[swampboy]

Well if we need to come down they gonna have to add me a jack plate... Can't come down any lower... We in the second bolt hole on the motor plate..

[meaux fishing]

This is what it should look like
ImageUploadedByTapatalk1425442420.834718.jpg

[meaux fishing]

This is too low
ImageUploadedByTapatalk1425442535.232746.jpg

[RichWentFishing504]

Yeah that's the pic I was looking for. If you can get your motor to do that it's the right height.

[keakar]

by any chance do you have a jack plate on the boat or does the transom have a little more angle to it then the average boat?

how is the motor set in the bracket? is it in the bottom "last" holes or do you have room to lower it more?

how the weight is distributed in the boat makes a big difference as well, is the weight of everything and gear spread out evenly?