Pacemaker Boats

[merwin10]

Andy -

Under the prop calculation topic you asked about what I meant about rudder alignment - so I thought I would try and answer it here so it would not get lost -

Basiclly there are several alignments however you can only adjust for one - As you remember I said under the prop selection topic I discussed drag and sid one of the points of drag that is overlooked often is misalignment of the rudders -

First rudders are mounted in the hull so that the center line of the rudder is offset from the centerline of the propshaft - The reason for this to compensate for prop torque - So when looking at the rudders from the back of the boat the centerline of the rudder will be right or left of the depending on the torque moment -

Now for alignment - the aligment I was referring to is the rudder to rudder alignment first both rudders must center at the same moment with a preset toe - the toe can be either in or out - After some experimenting I use 3/4" toe out - It seems to keep the rudder chatter down while keeping drag to a minimum - Oh why toe the rudders? When a rudder is straight there is little force on it and there is little drag so they tend to chatter with the result being wear on the steering gear - By toeing the rudders you put a positive pressure on the face hence keeping the vibration chatter to a minimum - see below -



Each boat is a little different and it takes some time to figure what it best for your boat - The reason is that whether or not you toe in or out and by how much is based on the centerline position of the prop shaft location on the boat - The important thing is that the rudders are equally toed from center position -

Well I hope this helps -

Mike -
_________________
"Best part of Boating -- is the people you meet"

[Tide the Knot]

well Mike it doesn't get much clearer than that.
That you very much for your help. I will keep you posted on my findings.
-Andy