Author Topic: What props for a twin 750 hp Stinger?  (Read 2035 times)

Ace

  • Newbie
  • *
  • Posts: 9
What props for a twin 750 hp Stinger?
« on: November 21, 2012, 04:01:11 pm »
So here is my first question for my newly acquired 390. The boat has no propellers at the moment, and it has SSM 3 drives with 19 splines. I found a pair of Rolla Cleaver 4 blades 17.75x22, would they be suitable for my application?

ccstinger

  • Hero Member
  • *****
  • Posts: 1669
Re: What props for a twin 750 hp Stinger?
« Reply #1 on: November 24, 2012, 08:43:45 am »
A friend of mine who owns a 390 (he's on the board but replied to me by email) said about the props:

if the engines are stock 420's with TRS then a pair of stainless

Mercury Revolution 4 blade 14/1/2” x 19P
I find these worked the best as the engine runs at around 5200rpm at wot and it seems to get the best speed for the jull and hole shot.
I tried some clevers two years ago and the boat was a dog gettign out of the water onto lane but top end was impressive. Stock drives are too deep in the water for clevers.

Ace

  • Newbie
  • *
  • Posts: 9
Re: What props for a twin 750 hp Stinger?
« Reply #2 on: November 24, 2012, 09:25:18 pm »
Thanks for the input. Actually the boat has twin 480 cu with around 750 hp each so 1500 hp total ! The drives are Speedmaster 3.

stinger390x

  • Full Member
  • ***
  • Posts: 186
Re: What props for a twin 750 hp Stinger?
« Reply #3 on: November 26, 2012, 12:54:32 pm »
Hi Ace. That was me that gave the info to Han who was trying to help out.
I see that you have some powerful engines?!?!? Cudos!

Those clevers sound good to try out and I would be interested to see what RPM and speed you get from the 390?

If you start with those then see how it gets out of the hole... If its lazy then you have too much prop. That's a quick start.
Then you have to see what speed is your top end and check your engine rpm. Teasonably the big blocks should spin around 5200-5600 rpm and they will be screaming! Don't let them go over 5600 as this might cause damage to the bottom end os the blocks.
Top speed (realistically without exageration) should be about 75-85mph with that hull and that setup as you describe. Thats a reasonable speed for a 9500lb boat of that size and you will be burning fuel quite a bit!
My boat does about 58-62mph but I don't have the hp you are describing.

Mercury has some new five blade props for performance that i saw at the boat show last year. they tried to sell me a set but I opted not to buy then. I just put a few knicks on my props and might break down and buy them this winter at the show instead of sending my four blades out for repair.
Maybe we can talk again when boating season opens up again. (not sure where you live if you boat all year round?)