Stock Gas prop = 18" Stock Diesel prop = 20" - How big did you go?

[370Dancer]

I'm sure this will stir up some controversy........
Have you increased your diameter over the stock props, and if so, how big did you go?
anyone have any science on the minimum clearance in the tunnel before xxx starts happening (besides hitting the hull, guys..)
I will be researching the great know it all, but am also looking for practical application.
Thanks

 

[Stee6043]

I was going to make a post in that "props for sale" post about the difference between gas and diesel but decided against it

I think you'll be dramatically disappointed with the results but this is based purely on how I see my exact boat behave with gas vs diesel at low speeds. I have dock neighbor with my vintage 400, but diesel. The low end grunt couldn't be more different between our boats. It's not just the diameter, as far as I know, but also the full spec (cupping, pitch, whatever else?).

I'd be mildly concerned with damaging your transmissions. They may not like the stress of spinning those diesel wheels when shifting forward to reverse in docking scenarios.

But again, I have no direct experience with the application so please feel free to ignore this entire post! ha.

 

[370Dancer]

I was going to make a post in that "props for sale" post about the difference between gas and diesel but decided against it

I think you'll be dramatically disappointed with the results but this is based purely on how I see my exact boat behave with gas vs diesel at low speeds. I have dock neighbor with my vintage 400, but diesel. The low end grunt couldn't be more different between our boats. It's not just the diameter, as far as I know, but also the full spec (cupping, pitch, whatever else?).

I'd be mildly concerned with damaging your transmissions. They may not like the stress of spinning those diesel wheels when shifting forward to reverse in docking scenarios.

But again, I have no direct experience with the application so please feel free to ignore this entire post! ha.

I have diesel boats and gas boats. The very first 370 I ran for Marinemax was a Cat 3116 rig. You can imagine how underwhelmed I've been with the gas version ever since. I may not use those props you are referring to, but it does raise some questions I don't have answers to. Reading up in Yachting, there are builders who are getting away with 5% or less clearance in tunnels without vibration or cavitation. Still looking for a practical experience answer to lead me or make me run away. I've got time. Anyone know what the tunnel dimensions are, or do I have to jump in?

 

[quality time]

I increased the diameter by 1" on my old CAT powered 380DA with no ill effects.