33 express F300 props

[JJ2468]

This has been talked about before and including myself.

I love the engines after 3 season and 500 hours but still struggling with props. Usually run the Yahama 17pitch 3 blades. Messed around and had tuned three times a set of rev4 4 blades but still not happy. Sure the hole shot is better but 1--2 knots slower at cruise and exact same economy

Since many people have repowered these boats now what props is everyone running and are you happy ?

Anyone with 4 blades and if so the type and performance ?

 

[everwhom]

Hey JJ,

We've chatted directly on email on this. Having run my F250 XCA's a decent amount this season, I can say I'm very happy with the 15 pitch Mercury Thunderbolt (aka Mirage) props. I'm running about 30mph at 4400 RPM cruise getting pretty much 1 to 1.1 mpg fully fueled with a small crew (of relatively small people). Top speed is about 42mph at 5500 RPM. (all statute miles not nautical). Hole shot is fine - comes right up on plane with little bow rise.

Grady's performance bulletins have their F300's (and F250's until they dropped the option) with the 15 pitch SWSII, which I'm told are nearly identical to the Thunderbolts. I would have gone with the Yamaha props but they were unavailable back in the Spring. I'd recommend the Thunderbolts as they are also less expensive.

 

[HMBJack]

Not really applicable to your question but...

I have F250's on a 2006 330 Express. Ran the F250's for years with the Yamaha SWS 3 blade 17 pitch props.
Because I use my boat in the ocean 100% of the time (pretty big swells here in Northern California), I felt at times I was lugging the engines with some degree of prop slip. The boat is usually quite heavy with full fuel, safety equipment, crew and ice. Two seasons ago, I switched to 4 blade 16 pitch props.

No more prop slip and I can power through the back of a 6-8 foot swell now rather than have the boat bog down behind it. It's like I have an extra "gear" that I didn't have before.

In comparison, here are the results (speed is in knots so multiply by 1.15 if you want statute speed):
With 3 blade 17" Pitch: 24 knot cruise at 4,800 RPMs
With 4 blade 16" pitch: 24 knot cruise at 4,300 RPMs

Same economy (1.0 MPG). Lost a little on the top end but it was a fair trade as I wanted the engines to work less hard at cruise and have more bite in the water. I would imagine on F300's you would see something similar to this - just at higher speeds! Good luck and I hope this is helpful to you.

 

[JJ2468]

What brand and type of 4 blade props in a 16 pitch ?

Would be very interested in trying a pair

 

[HMBJack]

I purchased them from PowerTech. They are the "OFS4" models.

No affiliation - below is their web site:
http://www.ptprop.com/index.php?option= ... e&Itemid=1

As you may know, a 16 inch pitch is uncommon. Props usually come in odd # pitches. PowerTech had to make them for me. I did not want to go to a 3 blade 15" nor a 4 blade 15" pitch.

The 16" pitch on a 4 Blade seemed "just right" and - it was - for my boat.

The OFS props came with a shift dampener which is noticeably quieter than with the Yamaha SWS props I had.