counter rotating - port or stbd?

[martini]

Does anyone know if it matters which way round the motors are on a twin c/r outboard set up? Is there an industry standard that everyone sticks to?

Thanks

[karlT]

Top of blades moving towards each other. So clockwise rotation on port and anti clock on starboard. Think it has something to do with density of water and surface so any sideways movement of water is pushed together nearer surface?

[Dirk Diggler]

Originally Posted by karlT

Top of blades moving towards each other. So clockwise rotation on port and anti clock on starboard.

Are you sure about that, it's usually the other way round!

[martini]

Google has it 9:0 in favour of counter rotate on the port side. How sure are you Karl?!

I'm still none the wiser about the theory behind it all

[Limey Linda]

Originally Posted by martini

Google has it 9:0 in favour of counter rotate on the port side. How sure are you Karl?!

I'm still none the wiser about the theory behind it all

Just called my Merc. mechanic who is factory trained and a 20 year offshore racing mechanic. Conventionally most riggers will mount counter rotate to port. Howver on racing boats they do it the other way round. as Karl suggested. Reasons: cleaner water turning towards each other, can mount them higher on the transom and run a higher rpm and the boat will be more stable.
Hope this helps.

[martini]

Originally Posted by Limey Linda

Just called my Merc. mechanic

You didnt do that just for me did you?!

I dont think we can class my rib as a racing boat so port it is then!

Cheers Limey

[Dirk Diggler]

Originally Posted by Limey Linda

. Howver on racing boats they do it the other way round. as Karl suggested.

That isn't strictly true.... Turning out is normal, but turning in does sometimes work better, although it nearly always gives trickier handling.

[Petrov]

Its ften a counter on starboard gives more bowlift (not in all cases, depends on engine porp etc etc)

[Limey Linda]

Originally Posted by martini

You didnt do that just for me did you?!

I dont think we can class my rib as a racing boat so port it is then!

Cheers Limey

Right decision I think. I hope you have ordered a factory manual. They have excellent installation instructions. Well worth the money. About $70.00 I think and you can order on line using your engine serial number.

[Matt]

Listen to dirk!!!!!