Catalina Helm Vibration Under Power

[Mike Carlson]

I recently test sailed a Catalina 28 MKII. Under sail, the helm was very smooth. Under power, the helm vibrated. In other words, the wheel rotated clock wise and then counter clockwise, about 1/4-inch or more, at a very high frequency when using the engine. The faster the engine went, the worse it got. It also wanted to make a very deliberate left turn under power. It was quite a fight. Is this normal?

 

[Stan Rogacevicz]

Left turn = Prop Walk

The tendency to steer to the left is caused by the normal windmill effect of prop walk of the stern to starboard in forward and port in reverse. Unless you get an AutoProp or some other feathering prop - they all do it. The vibration sounds like it may be engine/shaft alignment. Have that checked out.Stan"Christy Leigh"c320 #656

 

[Charlie]

Rudder vibration

I own a 28MKII and I don't have that problem so what could cause it on the boat that you test sailed? I have a standard two blade prop from Catalina. Since the prop is directly forward of the rudder I would suspect that turbulance from the prop and the effect of the Tide may be the culpert. I have noticed that when the tide is strong 3-4 kts and I am motoring at 2000 rpm against it, some vibration is evident. However, I suspect this to be normal. I am sure that you were not sailing this boat on a calm day. Hope this helpsCharlie