|Subject: T500 Folding Prop?|
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Date Posted: 4/02/04 12:40:17
I am in the process of fitting a new Beta 13.5 into "Swiftsure" in Kinsale. I thought I might go "the whole hog" and change to a 3 bladed folding prop-you only live once!
I have just realised that there is very little clearance between the back of the current two blader and the rudder ,when the rudder is turned 180 Deg for reverse! I am unlikely to be able to fit a folding prop for this reason?
Is it worth considering the folding prop at all. My engine supplier tells me it is woth 3/4 to 1 knot at crusing sped-this is attractive!
Has anyone fitted one successfully? Was it worth it?
Could I simply prevent the rudder from turning 180 with a mechanical stop system and retain the clearance? I would have to wrestle the tiller in reverse!
General question on Props.
On older boats with thick full length keels the shafts were marked so the the prop could be locked in paralled to and in line with keel. Thus minimising drag when sailing(With a two bladed prop).
I am continuously advised to lock my shaft when sailing so the prop does not spin.
My belief is that this only helps if you have the old long keel and the prop can be locked in the shadow of the keel.
I believe that if you allow the prop to spin, free wheel, while sailing that it will revolve, in reverse, at a speed dictated by the current sailing speed. The only energy loss will be the friction in the prop shaft. If you lock the shaft the prop will create much more drag!
I may be stoned to death for this theory! Anyone out there with the facts?
Regards to all,
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