01 36 Spectre

38 pitch 5 blade Herings
-2 imco shorties
Neutral Imco boxes
1.35 gears
6000 rpm 126 MPH

So wheres the problem? Should I try some spacers? Or loose the boxes? I'm thinking spacers cause I throw a mean rooster tail. Ive cracked 2 sets of props so far.

http://youtu.be/tvUv2v4ssPA

IMO the quickest and least expensive place to start would be to add a 1 inch spacers and try it, it will at least give you some usable information to start with. The video was Sweet but the tail looks very similar to mine. I run a 32 pitch at 6200 with 1.36 gears 11% slip on a 38 Ft cat. But I believe you need more water on the blades. I'm not an expert just my thought, assuming you are not running to much trim, and the rooster suggests no over trimming, I found my cat is most efficent at zero trim but each boat has it's own personality. Good luck, keep us posted.

2002 Spectre 36' Pokerun 600SCI. 1.35 36P bravo box stock props. 5800RPM on limiters. Has -2 sportmasters with 2" spacer back to standard length. No boxes. First time out with new motors. Have had boat several years previous motors 575SCI. I have cracked, broke and thrown multiple labbed sets of props over the years. No problems with box stock bravo's for the last couple of years. Except for the ones I loose to broken prop shafts and debris strikes.

So it looks like I need to hunt down some spacers, and if that doesnt work, remove the boxes.

21% slip is a ton. I may need to find a set of 6 blades I guess. x is 2" above the bottom