3 vs 4 blade, nibral or bronze

[Jeremyvmd]

So shady is getting hauled soon due to circumstances I don't want to get into until I'm done trying to get my insurance company to see reason/the truth...while I have her out again I'm thinking of getting the prop replaced, or at least tuned. I am considering going with a 4 blade rather than the factory 3. I'm also trying to decide if nibral is worth the premium in a slower/low power boat like the 28...I'm looking to increase efficiency and low to midrange performance and handling. Not too concerned about absolute top end as I rarely if ever run her anywhere near that...anyone running a 4 blade that used to have a 3 and can comment?

[Tree]

generally you are going to get a better cruise speed with a 4 blade - I am surprised you have a 3 blade on yours to be honest? What is your transmission ratio and what RPM does the engine sit at cruising?

[Jeremyvmd]

Don't know the rpm as my tach hasn't been adjusted, but working on that. Tranny is a 1.56:1 iirc, I'll check again on Sunday when I'm at the boat (hopefully tach will be adjusted by then too). I'm usually sitting at 15knts or so

[Tree]

I'm at 2.03:1 with the hurth gearbox. Generally running at 3300 rpm on the yanmar. Cruise speed is about 18 knots but then I've had a prop developed where the original was 19 x 19 with a 5 cup. I'm now running 20.5 x 19 ( I think from the top of my head) and a 3 cup. With the original factory, so far as I know prop I was 16.5/17 knots.

Max who's username is serenity has the original trans he had with his peninsular but now running a yanmar is running a 3 blade and has significant differences. I believe he tops out at 29 knots and can cruise at a comfortable 23. He's a good 5 knots on both WOT and cruise than I am.

[Jeremyvmd]

Yea I know tag team has a cruise of i think 20 with a peninsular and the same trans as me. But I don't know what he has for a wheel. I've done quite a bit of research on props over the past year or so, and with the new motor I was hoping to gain efficiency and possibly speed (but efficiency is #1 priority). In the end I'm likely to have a prop shop do the heavy lifting for me. But it's nice to have some opinions prior to taking that step

[Pedro]

What did you decide to do regarding the prop?, I'm doing my cutlass bearing this winter so while the prop is off I'm having it checked over, I think I'm at optimum efficiency already but looking to tweak it for higher cruise speed if possible,

[Jeremyvmd]

habent decided anything yet. Dealing with an insurance claim on her right now. Gonna depend on where the chips land as to what I'm gonna be able to do. If/when I need a new prop I'm gonna get a bronze 4 blade, but I need to get her back in the water to do more testing first

[Serenity]

Max here. Try calling Bossler & Sweezy to get a price on the prop at 6312860458. I have the same or close to it the same surface area with my 3 blade as I would if I had a 4 blade. How are the dogs.