Well, it was a grueling 5 days hauled out for work. Let me just skip to the prop parts.
My original fixed 3 blade prop took a tremendous amount of heat from an Oxy-Acetylene torch to get it off. The bronze shaft transmitted the heat so well that it melted the rubber components of the cutless bearing, which was being replaced anyway (as soon as the $#&!! prop came off!). Just FYI, the prop did not come off until later - I suspect the shaft cooled a bit faster than the thick prop hub and that allowed the 3000 lb hydraulic prop puller to finally get it off.
First, I used the Association's tool to replace the cutless bearing and even working solo, it was a pretty easy job. After cleaning up the shaft taper with fine emery paper and dressing any minor burrs, I added a thin film of anti-seize and installed the key, prop, nut and cotter pin.
On the way home from the haul-out/DIY yard, I immediately noticed that there was considerably more thrust at lower RPM. It was a no-current situation with minimal wind, so I could gage the results better. When I got to where I could apply full power, I reached only 2850 RPM vs the 3000 I could before, so I am somewhat over-propped.
Even accounting for the clean bottom, though, I achieved the same boat speed at 2850 with the Campbell prop as I did with the old prop at 3000 RPM, so I am not too concerned. For 98% of the way I run the boat, it appears that I will get more speed with the same 2200 RPM engine speed that I typically run. For those times that I run the engine at just 1800 RPM, it is much quieter and produces a lot more boat speed.
That's all for now. We can discuss more later.
Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/
Duane,
What pitch and diameter Campbell Sailor did you end up with?
Tom & Janis Grover
C36 #0949
SR/WK, M25XP
Midland, ON
Tom,
I have no idea how I failed to include that info the first time - still exhausted, I guess.
My original was a 15 dia x 9 pitch and the Campbell is a 14 x 8. It obviously has a different design by the looks and it is surprising, on the surface of it, to have more thrust with a smaller diameter and pitch. I will not be able to gauge very well how much less drag there is while sailing.
Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/
UPDATE:
I have run 2 tanks of fuel now with the new prop and can report anecdotally that the fuel consumption is roughly the same, and possibly lower.
My engine RPM varied somewhat on different passages, but it was generally in the 6.2 knot range (no current, waves, or wind). Pushing the boat at a given speed takes the same amount of power in the form of thrust at the propeller. Achieving that thrust at a lower engine RPM should theoretically offer some extra fuel efficiency as the engine friction losses are reduced.
My usage was not tracked carefully enough to say for sure that fuel economy is better, but I sure love having the engine working in a lower RPM band for the noise reduction that offers.
Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/