SHAFT

[dsw]

Is there a rule as to how much shaft should be showing from the cutlass to the
Propeller as after searching and reading some say 4 times diameter of shaft
And some say no more than 1 times the shaft diameter ?

 

[vyv_cox]

No more than 1 x shaft diameter makes most sense and is the rule I have always understood. A propeller has considerable mass and sometimes applies a lot of lateral force. The closest that the bearing can be placed to it, the better. Even with that rule it is clear that there is a resonant frequency on my boat at around 2000 rpm (engine). Having the prop sticking out of the bearing by x 4 diameters would make that situation far worse.

 

[Topcat47]

On my long keel boat, the cut out in the jul/rudder for the prop doesn't allow more than 1/2". Agree with Vic, it's kinder on the cut less bearing, too, even with a properly balanced prop.

 

[Tranona]

1* diameter is common, although if you are fitting a rope cutter typically you need nearer 2* diameter. This does not seem to cause any problems.

 

[dsw]

ok thanks I was concerned about the so called dead wood area and if my 4 blade 25 inch would pick
the water up ok.