Overcoming Prop Torque

[pelicanpete]

I own a 24 ft open centre console boat with a single Yamaha 225 h.p. 2-stroke outboard. It is not fitted with trim tabs and the problem I am having is that, under power at all speeds, it lists to port. If I have people on board I ask them to sit/stand on the right side which levels things up. But when I'm on my own, the port list is there.

I'll fit trim-tabs as a last resort but does anyone out there have a cheap and simple alternative solution to the problem?

 

[Talbot]

you could perhaps fit a permanent trim tab on the port side with a few degrees of trim. It would need to be adjustable and when the right angle is established, then made permanent - that would be a lot cheaper than a proper trim tab.

 

[BrendanS]

Several crates of beer on the starboard side, and keep replenished as you drink them

 

[tcm]

I do not believe it is "prop torque". Else it wd be there a teeny bit when accelrating to a slow speed, whereas accelerating harder it wd kerwham the boat on its side, or even spin it like a corkscrew.

Note that once there is a list - the boat will naturally accentuate that list if lots of heavy things on board are liquid, like fuel and water, cos they will go downhill. So correcting the list at rest will sort it.

Get something heavy and move it over to the other side. It could be heftier batteries fitted frinstance. Or brendan's drinks idea, obviously.

 

[brianrunyard]

You could ask Here

 

[powerskipper]

Could it be that either the engine is not lying vertically or it is slightly off to one side, both would give the effect you mentioned.

 

[No1_Moose]

ah, won't the boat appear to list and or spin more with this option?

 

[tcm]

yeah, but it can still be adjusted by drinking in the other direction

 

[No1_Moose]

didn't think of that, perfect solution.

 

[pelicanpete]

Thanks for all the suggestions. Beer is so expensive where I live, it'll be cheaper to buy a new boat!

Thanks, especially, to the one constructive reply...

 

[DAKA]

It could be your tab slightly out.
Your engine should have a sacrificial trim tab fitted, (small inverted shark fin near the prop)
If you adjust this to steer to port (angle to the left) then you will find you steering wheel can move slightly to steer to starboard to compensate, that will get rid of the port list.

I presume when you let go of the steering wheel the boat steers to starboard slightly.


I think the case of beer is a good idea, equally a 20L jerry can would be useful. Even if you get your trim 100% accurate there will always be a side wind which will knock you off trim.

3 choices

a) case of beer

b) jerry can

c) dolly bird in scanty bikini (seen here trying to get bow up )

http://www.pdb1.co.uk/imagepath/b04cc6a4ea23d7b3dbf92f8a268de5ef.jpg

 

[Nautorius]

Hi,

Not in the same league but I had a 17ft sportsboat with an 85hp on the back. It suffered the same problem. Solved it by fitting a Dole fin on the engine leg. They can be individualy adjusted and with trial and error (took about 2 hrs) I adjusted them to solve the problem. This was a light boat and engine package though. Another alternative I used on a 22ft sportsboat was a Flexi Water tank. I put it under one of the Port side Lockers and when on my own filled it up (same weight as me) so it evened out the lean. Then just used a simple pump to empty it. Not very Hi tech and cost about £100 to fit and a few hours.

Cheers

Paul

 

[zeros]

Your engine should be offset to one side to compansate for this, saying this I used to have a rib and at high speed in flat water it used to lean to port with me helming from the starboard side.

 

[stelican]

What make is the boat?

 

[ArthurWood]

I would think that DAKA's suggestion re the trim tab is the first thing to try.

Adding a Doel fin might make things worse - it did for our 19ft boat which almost corkscrewed on acceleration!

 

[pelicanpete]

[ QUOTE ]
What make is the boat?

[/ QUOTE ]

It's a Pursuit 2355 centre console fishing machine.
Me: Brit (Living in Bahamas, sometimes in the Solent area)
Boat: American
Location of both: Abaco, Bahamas.

Thanks to all for the additional ideas. Will try them all, especially the link!

 

[Nautorius]

Authur,

A doel fin requires set up like anything else. If you get it wrong then arghhhh. I am not presuming you did get it wrong though.

What engine/outdrive did you put it on?

paul

 

[Dave_Snelson]

Don\'t forget windage

Motorboats lean into the wind as a function of them being err, motoreboats. Don't forget to take this into account, as it could be one of the causes. (I realise it won't always be port side)

 

[ArthurWood]

It wasn't actually a Doel, but something similar, a Stingray, I think. It was many years ago and although I followed the installation instructions, the boat scared the proverbial out of me as I tried to get up on plane and suddenly tipped to pt if I remember correctly. It was fitted to a 1987 19ft Wellcraft Classic w/165hp Merc w/Alpha I O/D. Shortly after, Stingray provided trim attachments for the product, but never mentioned the danger of running without them. Fortunately the marina broke the Stingray on liftout and replaced it with another type which had slightly upward tilted wings with vertical wing tips (like a on a plane, but also projecting downwards). This worked like a charm. My son now has the boat in Georgia (US).