Boat leans after 20 mph

[Five O'Clock]

I own a 2003 Monterey, 25 foot cuddy.
Engine only has about 65 hours on it, but recently I notice that when i hit 20 mph or above, the boat leans aggresively to the left. So aggresive that I feel as if I don't slow down or correct by turning the wheel, that the boat will tip. This happened all season, I thought the trim tabs were working fine, but maybe not???

could it be anything other than the trim tabs or is that the main cause for the leaning after 20 mph?

 

[Five O'Clock]

Re: Boat leans after 20 mph

some more info:
it's an I/O stern drive with duo-prop

if anybody wants me to provide anything else please let me know.

 

[Maclin]

Re: Boat leans after 20 mph

If I thought the trim tabs were acting up I think I would try to get the trim tabs all the way up and disable them somehow, or even remove them, try it it that way to see if they are the problem.

 

[tashasdaddy]

Re: Boat leans after 20 mph

are you trimming your outdrive trim. adjust your trim, it could be pushing the bow down, causing this.

 

[Jdeagro]

Re: Boat leans after 20 mph

If you run with the trim too far down once you are on plane the boat will have a tendency to list to port (left if you are in the boat). However since you have a dou prop this should not be the case as the normal torque list is counteracted by the dual prop rotation. Yet the most common cause for a list to port at crusising speed is a torque list. Do you happen to have a hydrofoil on the boat as well as the tabs? What type of Tabs do you have on the boat?

 

[Five O'Clock]

Re: Boat leans after 20 mph

I have no hydrofoil on the boat, and the trim tabs are Bennett.

I've never adjusted the outdrive trim while cruising, even though its duo-prop you think this could still be the case?

I feel as when I adjust the trim tabs, nothing happens at all. no movements with the boat either way.

 

[QC]

Re: Boat leans after 20 mph

OK . . .

1) Push down (bow up) on both of your trim tab switches and hold them until your volt meter starts to drop a lot . . . this will indicate that they should be all of the way up . . .

2) Look at the back of the boat and determine if the trailing edge of both trim tabs are above the extended line of the bottom. The trailing edges should be higher than the bottom of the transom. If either one is below the bottom's surface, try the switches again. See if you can get the tabs to move. We want to know if you can get them completely out of the way. Above the imaginary extended surface of the bottom . . . If not, then I think we have found your problem and they need to be fixed . . . If they do come up, head to #3

3) Run the boat and see if there is any difference with them up. If there isn't then start to play with the trim (you should always use your trim to find the most efficient and safe running attitude. Use this coupled with your tabs when everything is operating as it/they should).

4) Please report back!!!

Good luck.

 

[geoloco5150]

Re: Boat leans after 20 mph

I also think this may be related to the way you are trimming the outdrive. We have a FourWinns 190 and it will behave similarly if trimmed down too far.

 

[tashasdaddy]

Re: Boat leans after 20 mph

I've never adjusted the outdrive trim while cruising, even though its duo-prop you think this could still be the case?

you have to trim your outdrive out, all the way in pushes the bow down, counters the tabs. you need to experiment, and learn your boat.

 

[KAR37922]

Re: Boat leans after 20 mph

My Searay did the exact same thing ? scared me to death ? I thought the trim tabs looked fine. But I found out that the fuse to the trim tab pump was blown.

 

[tnduc]

Re: Boat leans after 20 mph

If you run with the trim too far down once you are on plane the boat will have a tendency to list to port (left if you are in the boat).

Thanks for the tip . I noticed the lean to port in the past so when I went fishing this weekend I opened it up while in the channel. Trimmed the motor up- the lean to port all but stopped and I picked up 3 MPH.

 

[180shabah]

Re: Boat leans after 20 mph

And probably an extra MPG.

 

[magster65]

Re: Boat leans after 20 mph

Yep... every boat I've had will lean unless it's trimmed right... even the duo-prop units.
Get up on plane then trim up slowly to your best speed then fine tune any lean with your tabs. Look at your trim guage and see where it is then next time as soon as you come up on the step you can just trim it to that point and leave it. There will be some difference between the boats favorite cruise trim angle and it's favorite wot trim angle.