Roll Issue

I have a cruisers inc aria 2420 circa 1994 and we have an issue with the boat rolling to one side or the other with any type of wind or waves. it is very unsettling and we are not experienced boaters. even with using the trim tabs and levelers the boat will either just stay on its side depending on the direction of the wind or roll from side to side as we try to level it. its gotten to the point where we can only use it when there is no wind at all or we have to stay within canals or wind protected areas. we like to take the boat across the great south bay from long island to fire island. is this the design of the boat or is it our lack of experience? should we get it checked out mechanically?

 

You have a weight issue. Too much weight up high. You need to shift all the heavy stuff down as low as it can go. Aslo move it aft. Additionally, this type of planing hull boat does that to some extent. It's a phenomenon called dynamic instability. I've seen it in a number of boats. Which does not mean your boat is unstable. It is stable. But some boats when on plane tend to seek a more stable position which often is leaning one way or the other. A lot of things contribute to this, the hull design, the torque of the prop, the weight distribution. There is a lot of freeboard, so in a cross wind it tends to lean over away from the wind. About all you can do is what I've already said. Redistribute the weight. Bigger trim tabs might help but first make sure the ones you have are working correctly. Trim tabs that aren't working right can cause this. Also make sure you've got the right prop and trim angle on your sterndrive. You need to do these things anyway and they may correct your problem. Also talk to other owners of this model boat. See if they have the same problem. If all else fails talk to a factory rep.

 

Thanks for your reply. The only weight we have up high would be ourselves, we rarely bring more than a small cooler with us. What do you mean by the right trim angle on the stern drive?

 

Your sterndrive not only pivots left and right but also in and out. In other words the angle it enters the water relative to the face of the transom can be adjusted. You can tuck it in (the bottom is as far forward as possible) or you can tilt it out (the bottom of the sterndrive is as far back as possible) The tilt affects how your hull runs on a plane. If it is trimmed under, too far forward, it tends to lift the back end of the boat out of the water and force the bow down, which would lead to the unstable condition you have. If it is tilted too far out then it forces the stern down and the bow up giving your boat a bow up attitude and throwing a much larger wake. Both of these conditions slow the boat, burn more gas and are genrally inefficient. The best way to find out what the right trim angle is, is to get up on a plane at about 3/4 throttle and then trim the sterndrive in and out until the boat runs the fastest. Write down the rpm and the trim angle and the speed. Your boat should have an indicator that tells you what the trim angle is. In the future you can use this as benchmark to know if your boat is running properly.

If you need help with this go to the dealer where you bought the boat and get one of the techs there to show you how, or if you know someone who has been around these kinds of boats they can show you how.

 

I see you were asking this question on another thread. http://boatdesign.net/forums/showthread.php?t=12727
You idea to get someone local to help is good. They can actually run the boat and do a better analysis.

One other thing. If you know who the previous owner is, or can find out, ask them if they had this problem and how they dealt with it.

 

Try the article linked down here. Maybe something is said there about your concern....

http://www.highbeam.com/doc/1G1:151...ia motorboat) (Evaluation) (Cover Story).html