Power causing boat to list to Port

RussHaley · 26 July 2004, 13:04

Can anyone help?

A friend has a Fletcher Faro with a Mercury 100 on it. I'm not sure of the exact details of the engine, but it is a straight 4, autolube model, very tall and certainly not recent. I know it's not a RIB, but I think it is probably an engine problem and sure someone here can help

The problem is that although when at a standstill and at low speed the boat is level, as soon as the power comes on the boat leans to port, a good 10-15 degrees. The helm also pulls to starboard (again only at speed).

Any ideas? He's only recently bought the boat and this seems to be the only problem with it. I've never experienced this before on any powerboat.

His prop is a bit tatty and there might be a slight kink in the skeg, but it's very hard to tell. The engine has got bolt-on planing-fins added.

Any help would be appreciated.

Thanks,
Russ Haley

Mark Halliday · 26 July 2004, 13:21

It could be that the fins are not level or twisted.
Try taking it out without them fitted and see.
How is the boat loaded, if there is lots more weight on the port side (fuel tanks, battery, driver, lunch box, beer etc) it may be causing the list when on the plane.

Matt · 26 July 2004, 13:39

If it's level at rest, it's quite possible the engine needs to be trimmed out a bit when running fast.

Carl · 26 July 2004, 14:16

trust you to beat me to it,i was going to say that..........................as the old saying goes............ if in doubt...............................answers on a post card to

Nick Hearne · 26 July 2004, 14:26

Quote:

Originally Posted by carly baby

trust you to beat me to it,i was going to say that..........................as the old saying goes............ if in doubt...............................answers on a post card to

If in doubt give it a clout!

Well this is a technical term in the furniture trade!

Matt · 26 July 2004, 14:43

If in doubt...trim it out!!! lol

-Dan- · 26 July 2004, 14:47

Is the thingy that copmpensates for the rotation of the propeller adjusted properly?

Sorry for the lack of technical words

Dan

Nick Hearne · 26 July 2004, 14:52

"Trim it out" you lift/tilt the outboard up on the power tilt, if you not have power tilt then raise the stop bar a hole!

Simon Hawkins · 26 July 2004, 16:22

The balancing of the boat does not appear correct. It may be worthwile speaking to a propellor company to see if the correct propeller is fitted as this could list the boat to port at speed. You may also consider offsetting the engine from central position to remedy the proplem.

Nick Hearne · 26 July 2004, 16:32

I would go along with Simon about off set, some hear would say you do not knead it but on a small boat with a lot of power & torque the engine is trying to turn the boat!
Nick

Rogue Wave · 26 July 2004, 17:34

Quote:

Originally Posted by carly baby

trust you to beat me to it,i

Carl

That's about the only thing he will beat you to in Distant Mumble

I had this problem in the Scorpion, as slowing down wasn't an option I offset the engine a bit more and it helped. In a chat to Johnny Fuller about this he suggested I tried one manual trim tab on the oppsite side to the torque steer

Wayne Rogers · 26 July 2004, 18:13

Had a Faro myself with a 115 Mercury 2 Stroke,don't know if the engine was offset as it was allready fitted when I got it,I should take the fins off you shoudn't need them didn't have them on mine and she handled fine.

Matt · 26 July 2004, 20:18

Start with the easy stuff first.

Pete7 · 26 July 2004, 21:07

Quote:

Originally Posted by MadMat

Start with the easy stuff first.

I agree with Mat, take those wings off the engine, have the prop fixed and try different trim positions first.

Pete

tue · 26 July 2004, 21:13

Also check the trim tab (the small fin above the prop or the thingy that compensates for the rotation of the propeller

) is offset the correct way. When looking from the back all the way left for a left hand rotation engine.

Matt · 26 July 2004, 22:55

Whilst I do hate the wings, one assumes they were on a for a reason, mostly likely to make it plane easier or stop porpoising at some particular speed.

Matt · 26 July 2004, 23:05

This is a classic scenario of too much trim 'in'. Only when that has been discounted is it worth looking elsewhere. The trim tab will not change the tendency to roll, only the steering torque will change. The prop, whilst more likely to cavitate, may lose some speed, and vibrate a bit more, again, won't cause it. (The most efficient prop theoretically only has 1 blade

)

So I'm not saying it can only be lack of engine trim, just that IMHO it's most likely to be..

I bet the boat feels like it's trying to crab sideways too.

Searider · 27 July 2004, 10:04

Russ,

I would agree with the others - do the easy stuff first - put the engine back to how it should be.

ie.

1. Straighten the skeg - big adjustable spanner clamped in place
2. Remove the fins - I don't rate them if you have enough power
3. Refurbish the propeller - if its aluminium it should only cost about £30 - £50 and Steel Developments can turn them around in 3 days.
4. Play with the trim - trimming out should reduce your lean to the left.

Don't underestimate the effect a crappy propeller can make.

Regards

Duncan