I have a set of OEM B3 23's on my 23' Ebbtide with a 6.2. I was hitting 51-52 at 5100RPM's at 2300' with half tank of gas and a passenger. I have our local prop shop "add a little cup" to bump down the RPMs a little and add more top speed.

After the cupping the props looked a little rough at the tips. (Looked like they were hammered on.) Now after 30 hours or use I see some black forming in these areas.

Two questions:

- I remember seeing somewhere that this black is cavitation induced "burning" is this true and am I going to ruin them?

- Any better prop choice out there? I know my motor is spec'd for 4800-5200 RPM's but don't know if going up a pitch and bumping things down to 4800 would put her more in a sweet spot.

Worth mentioning that with 4 people on board she porpoises if you have the drive in any position other than straight down. Just captain and co-pilot I can trim out 1/4 up just fine. Don't know if this means I need more bow or stern lift or just get trim tabs.

Cupping should be specific, not random.

There are different B3 options. We (my Mercury time frame) developed props for decreasing cav burn.

Call us and talk to Brad. We will help you in your specific goals.

Brett