Re: 31 Ao
 

Try to get some slip #s before moving your drives. I have a
Chris Cat (same mold as AO)....set with props .75 in above the bottom. My setup is different being I use #3 drives and 17 in diameter cleavers.....but this can be a good guide. Remember at speed AIR should lift the nose not trim. My current setup has yielded better results than expected, hp is 736 (with 5psi boost on 509's),1.46 drive ratio and 32 pitch props, current best is 117mph on gps speedo. BAM has a great slip calcularor to help. Just my 2 cents. Good Luck! :drink:

Re: 31 Ao
 

OK now I will add my two cents worth. Without extension boxes the 3100 is slightly faster when the center of the nose cone is .25 below the bottom to .75 inches above the bottom but prop slip will be a little more than it was with the original 1 to 1.5 inches below the bottom that was used on the older boats. The lower the nose cone the greater will be the bow lift at the same trim setting. With extension boxes the center of the nose cone should be 1 to 1.75 inches above the bottom. If any higher than 2 inches the nose cone won't pick up enough water at speeds above 95 mph. Extension boxes with the right nose cone position will increase speed 2 to 4 MPH. Bow lift can be increased by cutting of the ring at the back of the bravo prop. the Lower X dimensions were used on the older boats because the 4 blade bravo props and 5 blade maxamus props which have good bite near the surface were not available.

Re: 31 Ao
 

I have a 31 foot awesome cat hp 500's I just installed 2" Mercury shorties and now I am 1" above the back of the boat with no boxes. I have bravo 1 drives with a 1.50 ratio. I tried it with a bravo 1 blade 30 pitch, which I was using before, and couldn't get it on plane. I was told that could possibly work if I go to a hydromotive 5 blade. Any suggestions?

Re: 31 Ao
 

Sounds a little high for your smaller diameter bravo propellers, My Chris Cat is setup about the same but I run 17 in diameter wheels. I have currently calculated my slip at 6-7%....736hp...32 pitch big shaft cleavers...1.46 drive ratio=118 gps mph best. On a side note I think a pointed ear prop will work best (tail lift) and My friends Awesome is heavier than my Chris and another local AO.Good luck. :drink:

Re: 31 Ao
 

thank's for the tip, But are you running a bravo dr

Re: 31 Ao
 

anything higher than 0.5 inches above the bottom without extension boxes and you will have a problem. the hydromotive 5 blade definitely bites better than the bravo 4 blade, but I would suggest the easy way out is to use a 1 inch spacer to make it just level with the bottom. only a small speed gain in going higher but it sure will be a lot more dillicult in getting the right prop to work.

Re: 31 Ao
 

thank for all tips