Need help with port "listing"

[w2op]

I own a 1996 Starcraft 1710 with a 3.0 Liter Mercruiser I/O. It runs great but at high speeds the boat tilts, or lists to the port side. Any suggestions for adjusting the motor? I want to avoid the expense of trim tabs if possible. Thanks- Mike

 

[Spidybot]

Re: Need help with port "listing"

Sounds as if you're hitting the hull's limit of balance. The higher speed you acchieve the higher your boat runs - eventually so high, that it runs on a very narrow portion of the hull (keel). As your prop turns clockwise, the thrust generated by the props grip in the water makes the boat move and the torque from the moving prop pushes the hull counterclockwise. Pushed over, the hull hits water more on one side and gets better lift, causing that side to come up. Next, the opposite side responds and comes up and so on. Also known, when extreme, as chinewalking.<br /><br />Read about prop stuff here

 

[w2op]

Re: Need help with port "listing"

Thanks for the information. I have been reading that a slight adjustment to the trim tab above the prop may help, only problem is which way to adjust- port or starboard?? Thanks for the help, Mike

 

[Spidybot]

Re: Need help with port "listing"

The trim tab is meant to compensate the steering effect from the prop turning.<br /><br />The mentioned link contains all about it, but anyhow you could experiment with it. Also check how trimming the lower unit, while underway, affects the problem.<br /><br />A more academic way to solve it would be a prop with less grip thus producing less torque, but this is useful only if your boat acchieves correct WOT rpm and performs satisfactory with it. Idea being, that your prop possibly has more grip than actually needed once up and running.<br /><br />Again, this is dealt with in the mentioned link.

 

[w2op]

Re: Need help with port "listing"

Thanks for the follow up. Trimming the lower unit up while underway does help level the boat out- if there is any chop on the water the boat porposes though. A simple amswer may be to put a little extra weight on the starboard side of the boat?? Mike

 

[Pursuit2150]

Re: Need help with port "listing"

Adjust the Trim tab aft edge about 3 or 4 deg. to port. There should be some marks on the bottom of the fins.

 

[w2op]

Re: Need help with port "listing"

Well I adjusted the trim tab and although steering was easier the boat still listed to port. I have heard that a hydrofoil may be a solution. Does anyone have any experience with these devices? Mike

 

[sony2001]

Re: Need help with port "listing"

You have to add a small trim tab to the left side of the boat.Small so it will be effective at high speed only.

 

[snapperbait]

Re: Need help with port "listing"

w2op: Try the hydrofoil.. Some of them have a money back guarntee so what do you have to lose..

 

[BassMan283]

Re: Need help with port "listing"

This is a long shot, but I'll post it anyway.<br /><br />About 20 years ago I was on a fishing trip with some folks and one of the guys had a new Lund w/ a 90 Johnson. We noticed that at WOT, he was listing heavily to port. As I remember it, it was decided that his transducer was mounted very close to center and was in front of one side of his prop causing cavitation. Any obstruction in front of your prop? Or did I just dream that?

 

[w2op]

Re: Need help with port "listing"

Thanks for the replies. today I purchased a Stingray Hydrofoil but wont be able to get on the water until late next week. Keep the comments coming as I am interested in hearing the experiences of those with similar problems. as soon as i get back on the water ( the "work" thing keeps getting in the way of my boating) I will post what happened. Thanks, mike

 

[w2op]

Re: Need help with port "listing"

Finally got on the water and the Stingray hydrofoil virtually eliminated the problem. As I increased speed and the boat started to list, the boat leveled out when I trimmed the motor up. I am able to trim the moter higher with the hydrofoil than before without porposing. Thanks for the advice and comments. Mike

 

[snapperbait]

Re: Need help with port "listing"

Glad to here you solved the problem..