Prop steer or "torque steer"

diamondjim

Member II
After 2 1/2 months of full time restoration on my newly acquired 1981 28+, I took the boat to the Yard to paint the bottom (first time in 4years). Before the yard, I installed a new Universal M-18 (Z500 kubota diesel), aligned the engine/transmission and propshaft and the machinery functioned perfectly. There was absolutly no pressure on the helm at any speed and no vibration.
During the stay in the yard, I had to replace the packing gland on the prop shaft which required moving the engine/transmission slightly to make the repair. I moved it back exactly to the same place and after launch, the helm wants to steer to port while under power. Even after repeated re-alignment attemps.

There was plenty of barnacles on the prop which were removed. No damage to the prop was evident. On this boat, the prop shaft sits just a few inches to port of the center line of the keel - therefore the prop thrust is partly on the port side of the rudder. Could this port side helm pressure be caused by a clean prop and bottom? Is this normal while the boat is under power?
 
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gareth harris

Sustaining Member
It is normal on my boat (E35-2). I have been told it is to keep the main prop thrust from going straight into the rudder.
Gareth
 

Merchey

Junior Member
My E27 has tremendous rudder pressure to port under motor power increasing with speed. I can’t let go of tiller without an immediate 90 degree turn to port. Under sail at same speed with sails balanced, no such pull. I have a tiller clutch that sometimes will allow me to let go for a short period of time. I’ve been told it’s just because of the turbulence from the prop close to leading edge of rudder and the shaft being slightly off center.
 

HerbertFriedman

Member III
My 1987 E34 also has a strong pull to (bow) port under full engine power, so much so that my auto pilot cannot keep a straight course but swings widely from side to side. But strangely enough, in reverse I notice little or no prop walk of the stern to port. Any explanations welcome.
 

toddster

Curator of Broken Parts
Blogs Author
If I must "hand steer" under power at cruising speed (usually because of traffic or narrow channel) I usually just lean into the tiller with my hip.
It's a 70's boat. Likes to boogie.
 
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