Rear of boat occasionally pulling down on port side.

[boatnut74]

I have a 1990 larson laser 18' with 4.3 Mercruiser. I have had it out twice and have a little concern with it. It will pull down the rear hard on the port side,almost feeling like it is getting pulled under. It has happened once each time it has been out and I can't figure out why. It concerns me as I have my family on board. It seems to happen around half throttle. The steering is tight and everything checks out good. It does have a light scum buildup on the port side bottom but I can't see that being the issue. Any advice would be appreciated.

 

[Another retired guy]

Does this happen when you are cruising on plane at half throttle, or while you are accelerating at half throttle but not yet on plane?

 

[rbh]

Yup, torque from the prop will pull a boat to one side, as well if your tabs are not working properly they will pull/push you over some (drag on one side)
Do you also have torque steer?

 

[boatnut74]

It seems to happen at half throttle when not quite on plane. It does not have a trim tab on the outdrive, just the flat anode. I havn't noticed any torque steer. The tip on one of the blades on the prop is bent over a little, would that be enough to cause this problem? I did order a set of smart tabs for it, I think they should help greatly with the issue.

 

[Another retired guy]

Probably a combination of things such as prop torque, weight distribution and insufficient prop thrust. Try getting on plane more quickly with a higher throttle setting. The Smart tabs will get you on plane faster.

 

[rbh]

It seems to happen at half throttle when not quite on plane. It does not have a trim tab on the outdrive, just the flat anode. I havn't noticed any torque steer. The tip on one of the blades on the prop is bent over a little, would that be enough to cause this problem? I did order a set of smart tabs for it, I think they should help greatly with the issue.

Here is what I would try, first make sure the drive is all the way in/retracted, Your hole shot should be 3/4 throttle +- to get yourself on plane.
When you get on plane back off on the throttle still staying on plane, then trim the drive out (watch the tach and speedo)
And trim tabs are the square+- adjustable metal pieces mounted to the transom on each side of the drive, they apply lift to the stern when in the down position.

 

[boatnut74]

I finally got my Nauticus smart tabs put on. The boat no longer gives me any handling issues. They were worth every penny.