Danny and Yvonne SIMMS
a little while ago someone posted regarding their SM pulling to starboard when under motor. A number of possibilities were explored by members. I think I have the answer. Today, my dawn departure from Whangaroa (Northland New Zealand)was windless and the harbour was glass calm. Motoring at about 7 knots and 2000 rpm I felt a pull to starboard on the wheel. I let it turn a bit and the pressure increased. Having just had her out for the biannual refit I know the rudder is perfect as is the propeller, the hull and the keel.
Later, sailing in light wind the helm was perfectly balanced. I think the starboard pull must by caused by prop wash (not prop walk) The rudder is quite a long way aft of the propeller and I suspect the turbulence from it must strike the rudder on the port side. This phenomenon is unlikely to be apparent in any seaway and would probably require a number of ducks to be in line. Likewise the steering would have to be very free turning, ie cables and rack and pinion in first rate order. Any stiffness would conceal the pressure. That's my offering..
SM 299 Ocean Pearl