Steering astern

[Tony Irwin]

If you put the prop into reverse while firmly tied to a pontoon, you will see the power of the prop walk by observing the powerful flow of water coming out from your starboard side as compared with the minor flow from your port side. Other things being equal, the turn to starboard is much easier than the turn to port. To make the point about steering even more strongly, I frequently see helmsmen reversing the direction of the tiller when putting the engine astern, as though the boat were a car doing a three point turn; better by far to keep the helm hard over, give a burst astern until she stops going forward and then give another burst forward until she begins to move forward; she will spin on a sixpence, except in wind strong enough to prevent her head from coming up into the wind.
Tony

[Peter Foston]

When I bought Khamis she had a two bladed prop 18 x 13 and when I spoke to Jeremy Lines he said that the props were overpitched (not oversized) for the reasons given by Tony Irwin.
I had the calculations done by two separate sources and both came up with 18 x 13. Before I constantly had sooty backside syndrome. Now I get absolutely no smoke.
I do, however get steady vibration in the tiller when motoring and wonder if this would be less with a three bladed prop. On each revolution the two blade is being shielded completely by the "Deadwood" of the hull which might be the cause.
Peter

[Peter Foston]

Correction to my last. The prop was calculated and repitched to 18 x eleven sorry!!!