Black Max vs. Apollo, Anyone ringside?

[hillca74]

Okay, gurus... Here is what I am currently running:

Larson Senza 186 runabout with 4.3L MPI Mercruiser spinning a 21 pitch 3 blade aluminum Black Max. With a light load, I'm seeing 4400 on the tach. According to the speedo, she'll do 53. While I'm happy with the top end, I'd really like to have a better hole shot and see more aggressive mid-range acceleration.

So, this is what I'm thinking:

4 blade SS 18 pitch Apollo. While the decrease in pitch should bump me 450-600 RPMs, I'm hoping the extra blade will offset that by 150-200. With that logic, I should see a net gain of 300-400 RPMs at WOT. THat should give me a WOT RPM of around 4800, the max for my motor. Of course, as the weather warms, I'd expect to see that drop just a bit, so no worries.

Now, is my logic correct, or am I not running on all cylinders?

 

[Tail_Gunner]

Re: Black Max vs. Apollo, Anyone ringside?

The Larson boat you have use's a Wellcraft hull, i have the same boat in a 2001.If you have a mpi or tbi engine, id first check you tach for the correct rpm,

If it is indeed correct a 18pitch stilletto bay pro11 would be a great choice, i gained 5mph going form a 19 p 3 bl aluminun to a 20p 4 bl

The boat came way out of the water, wake went straight out the back and ran much smoother, both the engine vibration and the hull,

 

[hillca74]

Re: Black Max vs. Apollo, Anyone ringside?

Well, I'm pretty excited about putting that prop on my boat. I'm just hoping that I don't get caught up in the trial and error pattern. I'll find out this weekend...

 

[hillca74]

Re: Black Max vs. Apollo, Anyone ringside?

Got a call today from my local boat shop. My prop is in! Ooh-boy... I'm just itching to get out on the water!