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Feathering Props
We have a three-blade Classic MaxProp installed on our Hinckley B-40. Last year, following a move that cut into my normal annual haulout we left the boat in the water for about 6 months longer than we normally do and without our monthly bottom wipe-down. When we finally got around to taking the boat to our favorite yard for annual maintenance, a trip of around 10 miles, the bottom was showing signs of hard growth forming along the waterline. As we pulled into the slip at the yard where we were to be hauled I put the transmission into reverse and found I had no reverse propulsion. We were only ghosting along so the yardman at hand had no trouble catching a line and stopping our forward motion. When we hauled the boat we found the prop and shaft completely covered in hard growth and found the prop jammed in a flat position - producing no thrust either forward or reverse. We had just motored over to the yard at a speed close to our normal boat speed under power and had backed and filled in the small channel leading into the yard turning the boat to align ourselves with the lift slip and the prop had functioned AOK. Just goes to show you that a MaxProp will jam if covered with sufficient hard growth and, as is said, at the most inappropriate time.
We installed the three-blade MaxProp in place of a two-blade fixed prop. The reason we did so was that we seem to do a lot of motoring and in any seastate where we were punching through 2-4 foot waves with a few larger ones we were constantly brought to a stop or greatly slowed. I know, I know, one shouldn''t be in a position to HAVE to punch through such sloppy seas but the "kids have to get back to college" or some such excuse always arises and so there you are. Anyway, the three-blade prop, while not giving us as much speed at top end (we lost about a half knot) seems to keep the speed up when we are faced with motoring through sloppy seas. The best feature of course is that when we do get to raise our sails the prop fairs itself with the slipstream and offers virtually no resistance to the passing water. We haven''t determined how much speed we''ve gained under sail but we think it is in the range of 1.5 to 2.5 knots. Interestingly, the previous owner had a device installed that, using pressure from the transmission (or lack thereof when the engine was shut down) to activate a braking cylinder, would stop the prop perfectly aligned vertically behind the deadwood to "hide" the two-blade prop in the aperture, but that didn''t seem to be as effective in reducing parasitic or flow drag as the MaxProp.
I would attribute the one failure we''ve experienced to my lack of diligence in keeping the bottom and prop clean certainly not a fault of the prop. Now that we''re settling down once again following the move we''ve established a monthly cleaning regimen that seems to be serving us well. At least the diver says he''s keeping the growth under control and so far this year we haven''t noticed any hesitancy in the MaxProp working as advertized.
A close friend of ours also has a MaxProp installed on his Phil Rhodes 58 and loves it.
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