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We have factory installed trim tabs on our 24' walkaround Marathon. In the full up position, the boat still lists a little to the port. It has been this way since we purchased it in 1988, and has really not been a big problem. We just touch the starboard side down a hair to compensate. This doesn't seem right to me. Shouldn't the boat ride level without tabs at all? It doesn't seem that the tabs, or at least the port side, are able to get up out of the way. We are thinking about redrilling the piston mount on the transom, but wanted to get some insight first. Any suggestions? I'd like the boat to ride a little more out of the water on calm days. It doesn't plow, but it does porpoise somewhat when the water isn't choppy. Wher could I get some specs?
Please, enlighten me, O great ones...
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Your trim tabs are probably installed right. Lots of guys put them on there to correct the listing.
A lot of guys have a weight distribution problem that causes the list in the first place. Do you have a kicker motor mounted on the one side of the transom? If so, are all your batteries on the same side?
If you have a bunch of weight on the one side, and then add a person or two over there, theres no way you are going to level out unless you move some weight around or use your trim tab to compensate.
One other thing you can do is adjust your torgue tab if you have one. It may help just a little bit.
I would bet the reason the tabs are there is to correct the list and you just need to shift around some weight.
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Thanks for the reply Predator. Regarding the torque tab; we did the next best thing and changed the prop direction to left. Kinda by accident, we just bought the wrong prop, but it did not make a difference in the list or the porpoising. I am still thinking the tabs need to be set up at some degree above the haul plane. Not sure how far though.
Everything is symetrical in the boat, including the batteries, one on both sides. No kicker motor either. Even when I am out alone, you'd figure the boat would ride a little to the driver's side, but it is just the opposite. It still wants to lean a little to the left.
Like I say though, we have run fine like this for 15 years, just thought we'd try to break something that wasn't broke yet!
Still looking for suggestions though. Thanks again.
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You may need to adjust the height of your engine. Are you getting a lot of rpm increase on the turns? Your engine may be too low in the water on plane, or it may need to be lower. Sometimes when the prop is changed and rpm is effected, you have to adjust the engine height.
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Ok. Now it sounds like you are referring to an outboard motor? The Marathon is an I/O... Don't think I can do much about lowering the motor. It does not have power trim either, only hydraulic lift when idle or stopped. We can adjust the outdrive angle manually with a stop pin on the lower unit, might that be an idea? If the angle in the water is not right, could that be cuasing the porpoising affect? Should the outdrive go further towards the transom or out away more?
Also, we had to put in a new motor this past year. The old block was a 305, now we have a 350. We have yet to get all the bugs out, so I am not really sure how well it is running. Looks like we may have it in the water this weekend. This will be the first time out since all the repairs on the U joint and shaft linkages were done last fall. I am anxious to see how it performs.
Once again, thanks for the input. I'll be watching for more.
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I dont know jack about in board/outs. But thats what I was thinking with the engine height. The shifting from side to side can be caused by inproper engine placement on an outboard. Plus, when you changed engine size, I assume you upped in not only H.P. but in rpm and torque as well. Did you change the prop?
If I were you, I would take it to a dealer and have them look at it. Have them drive it and see what they recomend. Or, just keep using that trim tab to correct the problem. One thing you can get to reduce the walking from side to side is one of those fins that attaches to the cav plate. That will give you a much wider and more stable foot to ride on. But if you are planing above the cavplate, it wont do much good. You would have to adjust the height of the lower unit, or prop it so that you dont run so fast and climb so high out of the water.
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Thanks for your help Predator. I will let you know what happens by next week. Hopefully we will have the boat floating by then. The mechanic who did all the work on the shaft last fall is wanting to water test it now, since it was too late last year to get it back in the water. I'll run some of your comments by him and see what he thinks.
Get ready Lake Erie, here I come again...
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