Pulling to the right

[MickS]

Maybe I should have rephrased my subject title..lol ::)

Anyway, I'm still fairly new to this powerboat game so still learning a few tricks.My boat always pulled to the right, so after asking a few other boaties there thoughts I learn that theres this thing(no idea of the name) that you can adjust on the engine , just above the prop to offset the spin of the prop.

So I did this, to find very little difference. So I'm out with my mates, having a bit of a fang in the boat, and I had a bit of a play with the trim, and I discovered that if I get the nose a little higher than normal the pull to the right goes away, infact I can let go of the wheel and the boat holds it's course.

Do you reckon this means I have a slight twist in the keel, or is there another issue?

[onerabbit]

Sound like you got the trim right.

Muzz

[litenup]

There are some questions. What sort of boat, how far in is the motor trimmed when you are "normal". could be you are trimming motor in too far to start with. Is the steering heavy, ie hard to turn, again could be trimmed in too far. Keep trying different things good luck. Pete

[MickS]

The boat is a 5.25 mtr bowrider(Stacer)When there is a bit of chop I trim down, and the boat pulls to the right.

It may just be a case of having the trim correct, but why the pull when I put the nose down a little. You can actually get to a point of no pull, a slight tweak of the trim, and the pull starts.

The steering does get heavy when trimmed down, but the ride is much smoother, in a bit of chop.

[Mr__Bean]

MickS,

A standard rotation engine will always pull harder to the right as you trim it down.

Nothing wrong with yours, it may be how you are trimming the boat or it may need a further adjustment to the trim tab. Ideally, your steering trim tab would be set to give you neutral pull when in cruise with a normal load and normal trim position.

To do this you adjust it by loosening the retention bolt and turning the rear of the tab in the direction that the boat is pulling, that is if the boat wants to go right you move the rear of the tab to the right.

Do this progressively until the steering is balanced to suit your boat.

There is nothing wrong with your boat or motor, the reason it alters with your trim setting is due to the water flow angle across the propellor changing as you trim your motor.

As you trim further down, the water is no longer passing at 90 degrees to the prop, so the prop blade that is on the up stroke is actually cutting through the water at a reduced pitch angle compared to the one on the down stroke which now has an increased pitch angle. The blade with the increased pitch pushes harder than the one with the reduced pitch which causes the motor to want to turn in the direction of the downstroke on the prop (to the right).

As you trim further back up, the upstroke blade increases its effective pitch angle (to the water flow) and makes the engine want to pull more to the left.

A note when setting the tab, it is much safer to have a neutral setting in the higher speed range than it is in the lower speed range, if you were to loose steering at low speed the safety risk is low compared to loosing it at high speed if the boat was to turn violently on its own.

- Darren

[MickS]

Thanks Darren, I appreciate your comments.

It's a simple explanations like yours that makes this site a valuable tool for people like myself who are still learning.

Cheers

Mick

[dnej]

Gees Darren,thats great stuff.Thanks from me also
David

[ahoj]

What size of motor?

[fishn-ads]

ahoj, Just a educated guess 5.25 Stacer bowrider pulling under power "90"hp, howed I go MickS?

[MickS]

Close, but not close enough...lol

115 hp 4 stroke.