Originally Posted by S/V Elusive
it wasn't an easy job getting all three blades on and in place, I'm a bit hesitant about having a diver do it - I'm screwed if something is lost
We pulled the boat onto the ramp
and changed the prop. It took two of us (4 hands) and I could not imagine doing this underwater. We didn't drop anything but I almost dropped on of the clamshells. Additionally, to remove the prop nut for the old prop we had to rig up a couple of 2X4s to get leverage on the nut. It would be tough to get leverage on that nut while neutral bouyant underwater.
Anyway, I set the prop up for about a 9 inch pitch
. We backed down the ramp
and I cautiously put it in gear
. At idle forward I could immediately "feel" the pull. Not so with the other prop. I advanced the throttle to about 1600 and as the boat accelerated the engine
speed also accelerated. I reckon this is a good thing as the engine
is loaded until the boat accelerates. A little lower pitch
would help acceleration but we aren't a drag boat. Anyway, it was thrilling.
Within a few seconds it stabilized at +6.5 kts and 2,000 rpm
. At 2500 RPM
we were probably at hull speed
and could see and hear "cavitation" off the transom. Any throttle push past 2200 rpm would probably be like pouring diesel
in the ocean for no speed change.
With the old folding prop we were getting about 3.5 kts at 2500 RPM.
Reverse performance was startling and I almost had the tiller ripped from my hands as the boat acelerated in reverse.
We were working against time as we had to get the boat out at high tide so the trial only lasted about 10 minutes. We'll do some better time trials when she goes back in next month but I suspect this swap to be a complete success. I think we will be able to motor
at +6kts at 2,000 rpm, saving fuel
, engine wear and tear and lowering noise
I am totally stoked.
We bought the donater a $180 bottle of blue label and laser engraved our boat name on it.