What causes a boat to lean during acceleration?

Question

Any ideas what would cause my boat to lean to the port side during acceleration? 1997 Starcraft 1710, 135 hp, 3.0 4 cyl. with a Mercruiser Alpha one second gen outdrive. Nohing bent or broken, it leans while coming on plane, once on plane it can be brought back level by trimming the outdrive up, but to get it level it has to be trimmed so high the prop will ventilate in rougher water. Any thoughts?

Answer 1

A boat could "list" to one side for several reasons, but it's usually a weight issue.  Too much weight on one side will make it lean to that side.  It also sounds like either the boat is underpowered, or there is too much weight on the bow.  I say this b/c you usually trim the motor Down to plane the boat, which brings the bow down.  You said you have to trim all the way up to plane out.  Double check the weight distribution on the boat, on the sides and even the bow and stern.  Think about battery weight, storage bins, gear, etc.  Maybe put more weight on the starboard side to even it out.

Answer 2

Hi there how are you? In answering your question I will agree on one thing as others have told. But there is more. Uneven weight distribution can effect boat performance and cause the boat to ride uneven. But where I disagree is in what some said about the boat being underpowered. You boat is not underpowered. For a 17' boat the engine you have in there is the normal rating for that size. Boat dealers will not underpower nor over power a boat that they sell. Your engine and drive are matched perfectly for that size of boat.  Second...in response to what someone else has said you do not trim the lower unit down to plane. In fact its the opposite. When you first start out you trim the lower unit all the way down. Where the angle of the drive is literately in a negative angle in relationship to the boat. by doing this you minimize the lift on the bow upon take off. Once the boat starts to plane you slowly trim the lower unit up. This in turn will bring the bow up thus reducing the amount of hull thats in the water. Thus reducing drag. Which will give you better fuel economy. Now you didnt mention how slow or fast you were going when you said you had to trim it all the way up. Your experiencing prop "cavitation" because your actually over tirmming it for the speed at which your going. The only way or situation when one puts the drive in whats called a "full power trim"  is when the boat is running full speed at wide open throttle. Have you changed props? Unless you have then the prop that came with the boat is the correct size and pitch. Has any work been done to the lower unti? I ask this because there will be two electrical switches called "trim limit switches" located on the gimbal ring. If this have been removed then there is a chance that they are not in sync with each other. In which one trim cylinder will actually be stopping at a different point from where the other will be. In that case that will kick the drive at a uneven angle instead of being level in relation to the boat. Yuo didnt state your age nor how long you have been driving boats but chances are your problem is being caused by uneven weight or what Imentioned about the trim switches. As far as your prop cavitating chances are thats because your not trimming it correctly. Using the tilt/trim is something that does NOT come automatically like people think. Thats comes from time and experimenting in different water conditions. Because every boat will react differently. If you have any other questions then feel free to ask.

Answer 3

Likely a combination of poor weight distribution and too small of a prop or incorrect pitch.