prop help 31' cat
 

i have a american offshore 31' with twin 540's approx 650 hp each, i am running bravo 1 outdrives 1.36 low water pick up but no nose cone, and prop shaft is approx 1.5" below the bottom of the boat. i have a set of 32p bravo 1 props i have been running and it is running approx 5000 rpm and 90 on my gps speedo. these props do not have enough to go thru the porpoising.dyno sheet for my motors is peak hp at 5800 i have been thinking of trying the hyrdomotive p5 in a 28 pitch. wanting to get my input on what i need to do, also thought about the imco shortys for a nose cone and get the props up a little more. thanks in advance

Something's not adding up... that boat should runs those speeds with 500hp's , do some searching in the AO & Awesome forum for some comparable set up's , I used to have a 31 Awesome with similar set up as you & ran easily 105-110 range , even prior to adding -2 lowers it would still go low 100's

when we calculated it out i was about 17% slip, what props were you running. i have ordered nose cone for my lowers and see if that changes my slip any thanks for the input

It's sounds like your prop shafts are too far in the water. They should be 1"-1.5" ABOVE the bottom.

I had one with 500 Efi's and it ran 92-93 on the limiters with 30p 4 blade bravos. Try raising you prop height.

I never tried 5 blades, even after I swapped out to -2 lowers (I did not have ext boxes) always had good luck with 32 Bravo's 4 blades, had some work done to them by Bblades to help carry the bow of the boat better.. fwiw

Spinellie bros prop company
 

Call me or email me. And we should talk, spinellie bros made a prop for me and I will never ever buy another brand, tell him I sent you and he will take care of you like a king, my name is jj jakubowicz. Call me

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