Prop size for 38’ Gulfstar trawler

[TrawlerDoug]

I just bought a 38’ Gulfstar trawler with bad props. Anyone know the correct prop size? It has 22’23” 4 blades. Twin 80hp Perkins. Props seem large. It’s on the yard and I want to replace before going back in water.

 

[Sailor of Fortune]

Maybe reach out to Roger long. I know he has a GS 36. Not sure if a single or twins

 

[kapnd]

That does sound like a lot of propeller for an 80 hp motor, but with a deep reduction gear, it might be correct.
Vic prop has a propeller calculator on their website, might be a good exercise to play around with that for some deeper understanding of what’s required for your particular vessel.
Any reputable propeller shop will run the numbers for you in hopes that they can sell you a prop!
Get ready by gathering some pertinent information about your vessels hull form, weight, reduction gear ratio, horsepower, shaft size, and target speed.
Also helpful to have the motors torque curve and fuel burn graph handy.

 

[High Wire]

Having no other information, the props have their dimensions stamped onto the hubs. The prop shop could put them back to original configuration as a baseline. Maybe the boats log book has some clues.