Prop Help/Suggestions

[Darwaypen]

I have a 2005 23' 5000lb Monterrey, I have recently replaced the original 305 MPI Alpha 1 Gen 2 with a 383 MPI and a Bravo 1.
The 305 prop was a 4 blade Solas 14/1/8 x 19. The Bravo drive i installed already had a Mirage 3 Blade 14 3/4 x 21 on it, it was hooked up to a 496 in its previous life. I also have a Power tech 14 1/2 X 16 that i have never run.
I took the boat out for sea trial with the 3 blade on it, it comes outta the hole pretty good, i ran it up to 4000 rpm for a bit and GPS speed was 48mph. Are any of the props the right size for my application? I am looking for a good all around prop, strong out of the hole with decent top end.
Just looking for opinions from you guys that have been doing this for awhile.
By the way, these forums were the ONLY way i made it through that complete motor and outdrive swap, thank all you guys for that!

 

[QBhoy]

If you’re numbers are right, you have about 1000rpm to play with more. If it’s doikg 50 now...jeez she will go well wot. You need to do that to see what numbers you get and go from there.

 

[Darwaypen]

Ok, thanks for that, will do in time, still breaking her in. I forgot, I also have a Hustler aluminum

4 blade​

14 1/2 x 17 .

The Bravo drive is a 1.5 ratio.

 

[Darwaypen]

Just to be clear, the initial run I made was with the 3 blade that came with the Bravo drive.

 

[QBhoy]

You’re at 11% prop slip just now with your numbers and if your drive is a 1.5. Even at 4000 rpm doing nearly 50 mph is astounding to be fair. Is it defo a 1.5 ratio ?

 

[Darwaypen]

That's what is says on the Mercruiser sticker on the drive.

 

[Darwaypen]

So i ended up putting my Stainless 4 blade Solas on, 14 1/8 x 19, she came outta the hole plenty hard, nose never even came up, ran her up to 4900 rpm, verified with my Snap on timing light, GPS said 51MPH. i think i'm happy with the overall performance of that prop. That 383 compared to the 305 is unbelievable! Thanks for the replies guys! ​

 

[QBhoy]

So i ended up putting my Stainless 4 blade Solas on, 14 1/8 x 19, she came outta the hole plenty hard, nose never even came up, ran her up to 4900 rpm, verified with my Snap on timing light, GPS said 51MPH. i think i'm happy with the overall performance of that prop. That 383 compared to the 305 is unbelievable! Thanks for the replies guys! ​

That’s a good result...the perfectionist prop geek in me would be tempted with a good merc 3 blade 19/20” prop for that little extra mph. I reckon a tempest plus would do really well on that.
Ill check your prop slip, but I have a feeling it’s going to be quite high with those numbers. A great investment for an mpi is a vessel view mobile kit at about $200. Amazing things. Will tell you pin point accurate data of every sort from your ecu. Exact rpm and Ps&Ts etc. Fuel calculator and all that...

 

[QBhoy]

Prop slip isn’t terrible to be fair...it’s 13% at those numbers. Not bad for a big hull like that and a 4 blade. A good 3 blade 19” would be little better of course with more top end...and you’d think the torque of that great new engine would manage just fine out the hole too.