Boat leaning to port while at plane speeds

[PPCS]

Hi Guys,

Having a wonderfull time with my boat I encountered a small issue. My boat is balanced perfectly when lying at the dock. However when I travel at plane the boat starts to lean to the port side and leans more when advancing throttle. I assume this has something to do with the propellor torque??

Can I correct this with the zink fin mounted under the anticavitation plate? If so to which side do I have to adjust the fin?

Thanks for the help!

FYI I have a 20" centerconsole with a 1999 115 Yamy V4 2-stroke 25"shaft. Max rpm is about 5200

 

[Texasmark]

Re: Boat leaning to port while at plane speeds

The zink fin is a trim tab but it's not to "right the boat" It's purpose it to offset prop torque as it has to do with steerability. If it is set right, steering to port or starboard takes the same effort and when taking your hand off the wheel the boat remains on course. Trim position affects it's performance and I set mine for the trim position I run at the most.

Trim tabs on the boat may solve your problem. I have had boats that do that and ones that don't. Obviously hull shape has something to do with it. Course proper engine height and alignment could also play in there. Where is your anti-vent (used to call it anti-cavitation but iboats corrected me) plate when you are up and running with respect to the water flowing out from under your transom? For most GP boats, it is at or just above the water.

HTH,

Mark

 

[PPCS]

Re: Boat leaning to port while at plane speeds

I have a hydraulical steeringrack, so I don't feel a lot of torque. However when at plane the steering wheel is harder to turn left than to the right. So the boat wanders to the right and I have to correct that in order to keep going straight. The only thing I notice is that the boat is leaning to the port side, probably cause by the "over" steering to the left to correct the propellor torque. At least this is what I'm thinking.

First I'm going to fiddle with the trim fin onder the vent plate.

I'll check the hight of the vent plate while running on plane!!

 

[guy74]

Re: Boat leaning to port while at plane speeds

I worked on a boat that did that, it was smaller than yours, but the cause was the skeg was bent. We straightened the skeg, and the lean while on plane went away.

 

[Bamaman1]

Re: Boat leaning to port while at plane speeds

A lot of times, a bent skeg will still track straight.

I would suggest you turn the tab on the cavitation plate slightly to the side that your steering is hard. It's a small adjustment that should easily settle your turning issue.

As far as a boat on plane leaning on one side. Fiberglass hulls are not always perfect. Also, boats are often not laterally weighted 50/50. I can promise you that a set of hydraulic trim tabs will take care of your leaning problem for under $500. They're also very easy to install.

Any planing hulled boat would benefit from trim tabs--great results for minimal cash outlay.

 

[Andy'sDelight]

Re: Boat leaning to port while at plane speeds

Prop torque. Turn the zinc fin's trailing edge slightly towards port, looking at it from behind. If this adjustment doesn't help then you need to check your motor height and your hull for any hooks.

 

[SteveRoss]

Re: Boat leaning to port while at plane speeds

Had that problem before too... I like
"guy74"'s answer. I let the "skeg" off at the pier and never had another problem.

 

[cr2k]

Re: Boat leaning to port while at plane speeds

Proper tuning of the trim tab on the drive is move it to the side that the boat goes when you let go of the wheel.

To andy'sdelight: The Port side of the boat is the same if you look from the back or the front.

 

[QC]

Re: Boat leaning to port while at plane speeds

Any planing hulled boat would benefit from trim tabs--great results for minimal cash outlay.

Strongly agree with the exception that I typically say "all V-hulls". Not real useful on a tunnel hull. Minor clarification, sorry for the hyper-correct carp . . . :redface:

To andy'sdelight: The Port side of the boat is the same if you look from the back or the front.

And that is why we use those silly terms instead of left and right . . .

 

[PPCS]

Re: Boat leaning to port while at plane speeds

Okai now you got me confused......

I'll try to move the zink fin to correct the problem, but I'm a little confused in what direction I've to move it.

Proper tuning of the trim tab on the drive is move it to the side that the boat goes when you let go of the wheel.

The steering is heavier to the left, than to the right, so the boat wants to go to the right I guess. (correct me if I'm wrong).
This means that according to you I've to move the zink fin to the starboard side.

Prop torque. Turn the zinc fin's trailing edge slightly towards port, looking at it from behind. If this adjustment doesn't help then you need to check your motor height and your hull for any hooks.

Okai so I'have to move it to the port side, no matter where I'm standing, port is port.

Had that problem before too... I like
"guy74"'s answer. I let the "skeg" off at the pier and never had another problem.

Is the skeg the same as the zink fin?? Mine is a little bit rough, This might have something to to with it?

Thanks for helping me out!!

 

[veritas honus]

Re: Boat leaning to port while at plane speeds

Is the skeg the same as the zink fin?? Mine is a little bit rough, This might have something to to with it?

The skeg is the bottom "fin" of your drive, below the prop. The zink fin looks like a miniature version. The skeg is what you will drag up the ramp (and down the road) if you forget to raise the outdrive (or motor if it's an O/B).

 

[Texasmark]

Re: Boat leaning to port while at plane speeds

It's real simple man. Get up on plane and set the trim where you like to ride at the speed you ride most often. Take your hand off the wheel and note which way the boat wants to go. Get somewhere where you can get to it and loosen, move, and retighten the trim tab....the little (1 1/2" long) tab that sticks down at the rear of the horizontal plate (anti-vent plate) that is just above the prop...........

If the boat veered to the right, move the rear of the tab to the right. The more you move it off center, the more effect it has. So, if the boat is just slightly moving to the right, then only move it a few degrees to the right.

Move it whichever way it needs to go until you can take your hand off the wheel as I said above and the boat tracks straight. If you can't get that, then you have some other problem.

Mark

 

[PPCS]

Re: Boat leaning to port while at plane speeds

Haha you're right it is absolutely simple, it is just that the hydraulical steering filters all the steering torque out.
This weekend I will run the boat and test her with the zink fin to the right! I'll keep you guys posted on how it went!

Regards,

Peter

 

[PPCS]

Re: Boat leaning to port while at plane speeds

Took her out today for some tests. I adjusted the zink fin to the right, and the steering is now perfectly balanced at cruising speed. At top speed teh steering to the left is still a little harder, but it is fine now. Concerning the leaning to port: After adjusting the zink fin the leaning to port is almost gone. At WOT the boat still leans a bit to port, but at cruising speed the boat is perfectly balanced. I'm gonna leave it to this and enjoy my boat!

Thanks for all the great help!!

 

[LX Kid]

Re: Boat leaning to port while at plane speeds

I've got the same exact problem with my '82 Grady White. Glad this worked out for you. I'm going to adjust mine and see if it corrects my port leaning problem. It's already adjusted a little but will give it a few more degrees and see what happens. I had an extended skeg put on mine and he welded it up a little bit crooked. Might even put a new tab on cause mine is getting a little eaten from corosion.

UPDATE:

I just went outside to check the tab and it was actually turned towards the starboard side. Loosened it up and turned it towards the port side. Here's couple before and afterjust to keep it interesting.

 

[QC]

Re: Boat leaning to port while at plane speeds

Yours may be leaning (listing) due to that hydrojawhammy being loose. I'd loosen it so much that it falls off and start over . . .

Let's keep this on one boat at a time. The trim tab on the drive is intended to adjust steering force port to starboard as many have noted. May help with the list, may not. But an arbitrary adjustment like that ^^^^ is sort of meaningless. Texasmark has explained this well, but a list to port is very normal with right hand propellers; twist something one way and the other stuff wants to twist the other way . . . If all else is right, the only real fix is trim tabs.

 

[LX Kid]

Re: Boat leaning to port while at plane speeds

Took her out today for some tests. I adjusted the zink fin to the right, and the steering is now perfectly balanced at cruising speed. At top speed teh steering to the left is still a little harder, but it is fine now. Concerning the leaning to port: After adjusting the zink fin the leaning to port is almost gone. At WOT the boat still leans a bit to port, but at cruising speed the boat is perfectly balanced. I'm gonna leave it to this and enjoy my boat! Thanks for all the great help!!

Glad you got your boat squared away. Maybe mine will now run truer. Had to stand passenger behind the wheel to get it to plane properly. Glad you posted this thread. Thanks

Nowhere to put trim tabs on mine.