Cat motor placement

[govomg]

Hey Fella's

Well after a lot of reading and discussion, I have bought a 5.6 Dominator, with 90 honda's. Looking at the motors from the back the motor alignment seems strange as they seem to be pointing outward slightly as if they are trying to rip the hull down the middle, is this normal on cats and will it effect its performance, it has hydraulic steering and has a valve that I can adjust to straighten them up or do I just leave them alone. Cheers Mark

[robothefisho]

Motor thrust should point towards the centre line of hull, is why cats throw up big rooster tails when the thrust combines.

So if thats what you mean by outwards, leave them alone.



So, port motor would be trying to turn the boat starboard and starboard motor would be trying to turn boat to port.

[Lovey80]

Do you mean that looking from the rear that when the motors are pointing straight that the front of the gearbox is pointing out wards on each motor or that the props are more to the outside than the engine so that the top is tiling toward the centre?

[John Buoy]

Hey Fella's

Well after a lot of reading and discussion, I have bought a 5.6 Dominator, with 90 honda's. Looking at the motors from the back the motor alignment seems strange as they seem to be pointing outward slightly as if they are trying to rip the hull down the middle, is this normal on cats and will it effect its performance, it has hydraulic steering and has a valve that I can adjust to straighten them up or do I just leave them alone. Cheers Mark

Congrats Mark gr8 boat and you will luv it!!

[govomg]

Thanks Fella's for you advice I will try them as they are and see how we go.

Thanks also John Buoy I am sure I will love it.

Cheers Mark

[cormorant]

Do a search on toe in and toe out on cats from ages ago

Your cat with a different hull design is slightly different set up. Set up is slightly different for non counter roatating set ups

Theory is that motors should be pointing in the exact laminer flow that comes under / around the hull for best performance and ecconomy. Ie the props push in the most effecient direction.

Truth is you can give your boat different characteristics by toe in and toe out and can also make them downright dangerous in different situations

Hydraulic tie bar set ups often weep slightly over time and the motors will end up toe in or toe out over a period of time due to the motors set up. They tend to get out of adjustment when being trailered and not secured as teh steering cylinders loosen up. A correctly set up motor on a cat with a correctly set up trim tab should be neutral but very few people balance them well if at all.

Really important to ensure there is no air in the hydraulic tie bar as under power motors will squeeze together or pull apart and at different loads will create different affect on hull.

Each style of cat is different and props are different

My suggestion is to one day when you have plenty of time and after you have read up a little to spend a couple of hours on smooth water.
Mark where they are in relation to each other. Ie measure distance from nose cone on gearcase to gearcase fully trimmed down and center of prop and write it down so you can always come back to it.

Go out and see how it performs, speed handling, lean attitude fuel use, revs.

Then set it to neutral , watch waterflow around motors. See how it performs. Any bad habits ( dolphining as you trimout etc)

Toe it in and then toe it out and see if you have any affects .

A lot of motor set up is about getting the right height and prop to start with and then combine that with the best adjustments.

I haven't had a play with that hull , won't comment, so don't know settings but others who have will . There are differences in the way symetrical and asymetrical hulls perform. Don't rely on other peoples boats as many have never been set up from the start properly however if you know someone who has theirs in a sweet spot is a good starting point.