Sunday, August 26, 2018

Testing over the hub cleaver on Selva Madeira 40

Today I made a test drive with Signature 10.5"x 18" over the hub cleaver propeller.
This was the first cleaver I have tested and compared to Signature semi-cleaver the difference was quite dramatic. On the first try I was not able to get the boat to plane, the outboard was screaming 6300 rpms which is 800 rpm over the maximum and still the boat was doing only 8 knots or so.

I was able to get the boat to plane when I moved myself to the center of the boat and the outboard was at WOT. With all other previously tested propellers the boat typically starts to plane extremely fast.

I guess the over the hub design, smaller diameter and Selva's quite large gear case is not the ideal combination but still I'm having hard time to understand why the hole shot is so bad.

Once the boat was planing the overall feel was quite good but still I noticed that the outboard was revving much higher than compared to Solas 11 x 17 round ear propeller.
I know that cleavers should be run very high, I don't have a jack plate and the outboard is mounted to uppermost position. However I was able to hit 6000 rpm without much effort so I think the problem not fixed by raising the engine even more. I think the propeller could have more pitch, maybe 20".

The top speed was a couple of knots slower compared to Solas 11" x 17" but I didn't want to push Selva over 6000 rpms.







No comments:

Post a Comment