The fact that steering is easier one way than the other (presumably to starboard?) is a function of the torque effect of the propeller - rather than anything to do with the propellor itself. Does the boat go in a straight line at speed if you let go of the wheel? If it snaps round to the right then you need to adjust the trim tab on the underside of the cavitation plate at the bottom of the leg. (little "rudder" shaped fin). If the boat does go dead straight then you may have some steering problems - is it mechanical (cable) or hydraulic? The revs decreasing would tell me that the throttle cable is being snagged and as you turn the engine it is throttling down.
Irrespective of the explanations, if this is a new RIB then your supplier should be sorting this all out for you! If they wont then I would name and shame them here - which supplier wants to get a reputation for selling a charity a badly set up boat!
At slow speed, there shouldn't be an appreciable difference in the effort required to turn either direction.
Was the boat supplied with the engine rigged and ready to go? If so, I suggest you get your supplier to remedy the problem. If someone else rigged the engine for you, see them as it's not likely to be a fault with the boat itself.
I work with a voluntary organisation which opperates a large rib.
At slow speed, it is difficult to turn one way and easy to turn the other. In addition, the revs increase and decrease when the boat is turned. How do we decide whether these effects are a fault (on a new RIB) or rather an effect of the propeller pitch? It is single engined rib with a 90hp 4stroke.
Neil
