22ft bay boat issues
 

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!!

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

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?

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.

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!!

Attachment 83564i 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.

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.

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

Is your cavitation plate just about even with your keel?

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

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..

Yes sir it's pretty even..

This is what it should look like
Attachment 83565

This is too low
Attachment 83566

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

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?

No jackplate... Our boat has less angle to me...

Is it possible you have a hook in the hull?

Something doesn't sound right. With a brand new boat you shouldn't need to add wedges to be able to cruise. Granted if you trim out to much you will induce a bounce on most boats but you shouldn't be porpoising at all with it all the way trimmed in.

I would post this question on thehulltruth forum. lots of very knowledgable guys there too.

I for sure would be all over the dealership on the boat not performing correctly though. Possibly testing another one of their boats to see if it does the same thing in another hull. Or get the dealer on the water and have them drive it, with you on it, and have them "show" you how your wrong and they are right.

I totally agree it's at the dealer now gonna see what they have to say... I'll post the solution when we find it lol

Glad to hear. Personally I would not accept them adding trim tabs or jackplate or wedges to a boat to fix an obvious problem if one exists. Again a ride in another seafox from the dealer would help out a lot too.

Maybe your motor shaft is too short?!?!

My buddy has the 24 Sea Fox Viper and had similar problems. Every issue went away when he went to a 4 blade prop.

Stern lifting prop might help a bit, either way I'd let the dealer figure it out and settle it if possible...It should be set up right from the get go with no issues.

Yup i highly recommend a turbo ofs1 it did wonders for me

your cavitation plate should be even with or just above the pad on your hull, water pressure should be above 15psi

hook in the hull will give you bow down force, ( it will not allow bow lift as much ) it creates a suction on the pad ( with hook )

K guys we got the boat back but we wasn't able to try it out due to weather,but we made them put the wedges which gave us plenty of negative trim actually about 4 more inches...I believe it should solve our problem... They checked out the cavitation plate an it all checked out good!

so what was it? did they have the trim stops set wrong?

there should have been no reason to install the wedges just to get more trim range out of it.

If your happy that is all that matters. Like everyone has stated a brand new boat should not require wedges for it to be able to ride properly. I'd be on that dealer like a fat kid on a cupcake. But again if your happy that is all that matters.

x2

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.

In 1994 I bought a Challenger 19 ft CC in Houston. Had a Mercury 135 HP. It had the porpoising issue too. Brought it back to dealer and they installed fins on the cavitation plate and it corrected the problem. These boats were made in Tennessee and are no longer in business.


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we had 0 negative trim on our boat... We tried different props... We gonna test it out this weekend I will let yall know