slow speed drifting and turning

[dspt69]

i am having issues with my coastrunner 440 when at low speeds is constantly turning when the wheel and engine is straight.

[Midnight]

Gday,
It will be turning and steering off the bow, instead of the keel. Try a few more revs to get the bow up a bit, if you are able.

Deep V hulls like mine and Haines Formula's etc are worse, the wake looks like the rainbow serpent at 4 knots, especially with someone new on the wheel!

Cheers,
Myles

[dspt69]

unfortunatley its the 6 knot areas that bring me undone.

[shrunken pojie]

Is it just turning to one side? If so, could it be the alignment thing down near the prop?

Phill

[dspt69]

no it turns both ways. i cant travel in a sraight line unless i am doing more than 15 knots

[White Pointer]

G'day,

Situation normal - almost.

What you perceive is the force of wind and current steering your boat more than engine and rudder under 15kn so that it's noticable.

At higher speeds on a plane heading for a landmark or plot point on your GPS it may be well doing the same but at higher speed you are constantly correcting for wind and current and waves and may not notice.

The outboard may not be set up properly. Suggest you wait for early morning with no breeze and see if it self steers. If it does, plot the couse on GPS and it will give you an idea of how much correction you need on the outboard leg.

Regards,

White Pointer

[sheridan]

My old Husky did the same i put a foil on the motor it lifted the rear at low speed it used to waddle like a duck 4 to 6 knots etc especially with a full tank of fuel at the rear hope this helps it just a thought

Geoff

[Midnight]

Gday dspt69,
Yep sounds about right. You will learn to live with it. Just try not to "oversteer" it, by that I mean don't chase it with big wheel corrections. Just watch it and let it wander a bit and make small inputs on the wheel when you have too.
Cheers,
Myles

[dspt69]

i might contact the dealer and make sure the boat was set up properly

[peterbo3]

Gday,
It will be turning and steering off the bow, instead of the keel. Try a few more revs to get the bow up a bit, if you are able.

Deep V hulls like mine and Haines Formula's etc are worse, the wake looks like the rainbow serpent at 4 knots, especially with someone new on the wheel!

Cheers,
Myles

Hi Miles,
Do you have a duoprop or a single. If the latter, do the volvo legs have the little trim fin that outboards have.

BTW, no more oil leaks?;D;D;D;D

[peterbo3]

i am having issues with my coastrunner 440 when at low speeds is constantly turning when the wheel and engine is straight.

G'Day dsp,
Does it wander when you are fully trimmed in or are you experiencing the problem with some trim out?

[shrunken pojie]

Has anyone experimented with a fixed rudder near the bow to counter this issue? I was having a look around the net for something that looked right and all I could find was stuff for Kayaks and sail boats.

[Midnight]

Gday Peter,
Hows things? Haven't heard you aout and about for while.

Nah mate, she is all good, touch wood haha I have done about 220hrs trouble free since that day you saved my @rse!

I have a duo-prop. It stops the wandering at about 5kts once the rudder effect from the leg and prop thrust over ride the deep V bow's keel effect.
The worst boat I have seen for this is the Haines 233 Formula, 24 degree V and the bow sits quite low when at slow displacement speeds.

But yeah, make sure it is all set up properly, but I suspect that the boat in question sits with a lot of the bow in the water and its bum up when going slow.

Cheers,
Myles

[Jarrah Jack]

Back to the origional question.....it can sometimes be a balance thing with the boat. If there is any bias then it is going to go off in that direction. It may be worth a play with...........or just put the beer in a holder for a while :)

[dspt69]

G'Day dsp,
Does it wander when you are fully trimmed in or are you experiencing the problem with some trim out?


fully trimmed

[black runner]

Hi

Sounds like the at-rest trim of the hull might be tending toward a bow down attitude. Try shifting some weight down aft if it is. You should be able to hold a straight course at under 15kts without wandering all over the place.

Also make sure that you trim the boat so that it is level side to side.

My current boat did this once at 5 kts, it was lightly loaded in the rear with 2 up front and an esky. Moved the gear down the aft end and all was good.

If this isn't the problem best get the local dealer to take a look for you.

Cheers

[dspt69]

Hi

Sounds like the at-rest trim of the hull might be tending toward a bow down attitude. Try shifting some weight down aft if it is. You should be able to hold a straight course at under 15kts without wandering all over the place.

Also make sure that you trim the boat so that it is level side to side.

My current boat did this once at 5 kts, it was lightly loaded in the rear with 2 up front and an esky. Moved the gear down the aft end and all was good.

If this isn't the problem best get the local dealer to take a look for you.

Cheers


yeh taking it out tommorow with 4 people so will see whether the wait in the back makes any difference.

[Noelm]

everyone move to the back of the boat, then see if it still does it, very common thing, the bow is steering the boat, not the motor, in fact what is happening is a "mini broach" weight in the stern will fix it for sure, but can be inconvenient.

[peterbo3]

dsp, could you try trimming out a bit & see what happens?

[dspt69]

took it out today. still having some issues. moved people to back except for me driving up front. did find though a adjustment rudder under the caviataion plate which i might have a play with next weekend. tried trimming out and this did sought of work but raised the bow way to much

[Noelm]

that's the only way to fix it, raise the bow, or lower the stern (by moving weight back) the adjustable trim tab probably will not fix the issue, and it may make it a bugger to steer at cruise speed (pulls to one side) if you fool around with it.

[dspt69]

that's the only way to fix it, raise the bow, or lower the stern (by moving weight back) the adjustable trim tab probably will not fix the issue, and it may make it a bugger to steer at cruise speed (pulls to one side) if you fool around with it.


actually good point. did not think of that. cheers i'd rather having to correct at 6 knots rather than at 25.

[dspt69]

Hi

Sounds like the at-rest trim of the hull might be tending toward a bow down attitude. Try shifting some weight down aft if it is. You should be able to hold a straight course at under 15kts without wandering all over the place.

Also make sure that you trim the boat so that it is level side to side.

My current boat did this once at 5 kts, it was lightly loaded in the rear with 2 up front and an esky. Moved the gear down the aft end and all was good.

If this isn't the problem best get the local dealer to take a look for you.

Cheers


sorry what do u mean trim the boat level side to side.

[black runner]

sorry what do u mean trim the boat level side to side.

As in the boat is not listing excessively to one side or the other. So before getting underway make sure the boat is loaded correctly both fore and aft and sitting level in the water across the beam.

Cheers

[black runner]

no it turns both ways. i cant travel in a sraight line unless i am doing more than 15 knots

I would be trying to find the cause of this. 4 knots maybe but not 8-15. Have you checked the alignment of the outboard leg in relation to the keel centreline. Is it centred? Do you have an external keel and is it straight along the length?

Cheers

[White Pointer]

i might contact the dealer and make sure the boat was set up properly

G'day,

The dealer will always say it was set up properly. A single engine on a dead flat sea in no wind will want to turn slightly to starboard unless the small fin on your outboard leg has been set to counteract this.

Like I said, take it out in a flat sea with no wind and see how it self steers. Plot the course on GPS and you will have a rough but pretty good idea of the adjustment needed.

Even after all this, the boat will not stay true to course except in dead calm. Wind and current are incredibly strong forces on hulls. It is tonnes of force in a bit of a blow.

Regards,

White Pointer