Prop Talk

[NICKYPOO]

All blades are not created equal. The pitch and diameter is only part of the equation. You also have blade count, cup, tranny, HP, torque, elevation, ballast, blah, blah, blah. Just saying a 13 x 16 is too tall is way too over simplified.

[Wickedcummins]

don't forget water density, At aprox. 4oC (39.2oF) pure water has it's highest density 1000 kg/m3 (weight or mass).

[cpropes2005]

Thanks guys for all of the info. The blade tips of my 13 x 10.5 where slightly tweaked so I stopped by a local prop shop last night and he is going to fix it and change the pitch to 11.5. I am thinking that will be a good compromise for what I am looking for but I will report back after running it this weekend.

[MoneyPity]

A key point is you do not want to exceed high rpm spec or rev limiter with the prop you use every day. If you are over revving with the prop you have you IMHO should talk with ACME after you document your boats rpms at WOT, cruising speed, and the time for 0-30 for holeshot. If you are cruising at 30mph and your RPM is well over 3000 rpm I would definitely pursue a different pitch. If rpm is running high at cruising speeds fuel consumption is probably higher than normal.

[chpthril]

Re-pitching the 10.5 911 to 11.5 basically makes it an ACME 653. So it will not be nearly as aggressive as the 10.5" pitch. Also, with the 1:1 gear, the ACME 3-blade props have been the ideal props as compared to the other common 4-blades found on other Tiges running the 1.5:1 i.e. the 537, 1235, 1273, 1433, etc. These will be dogs on a 1:1.

I think a 13.5 x 13 may be too sluggish in the hole-shot area. IIRC, the OEM was a 13 x 13 3-blade. That was really a ski prop and sucked when loaded with ballast. Going up in DIA is going to take even more power to turn. This may not be as noticeable with the 380HP if you boat at lower elevations or run a lot of ballast.

I would try the re-pitched 911 and then call ACME if you want further improvement.