Prop rings

[NickScheuer]

Anybody ever install a ring (Kort Nozzle?) on the prop of an A-25? Thinking of what it would take to make the boat impervious to lobster trap warps. The skeg along almost does it, but not quite "bullet proof".

[ssrig]

Are you looking for ducted or simply something to protect the prop? If you only want protection I believe forum member Kerrye has one on his boat.

[kerrye]

Yes we have a stainless cage around our prop. Boat was originally from Maine. Boat building friend of mine (Dave Laux— you know him Nick) thought it would induce a lot of drag. I suspect he is correct but I don’t know for sure

[kerrye]

The cage is visible in this photo.

enclosure top5.jpg

[kerrye]

Here's an example of one being fitted. If the lobster boats use them, they must be effective.

http://www.trawlerforum.com/forums/s6/p ... 10335.html

[DesertAlbin736]

Yes I could see where the example referenced on the trawler forum would be helpful in areas where crab and lobster pots are an issue. Not as much for preventing damage to a prop from rocks or submerged "dead head" logs and driftwood, but snagged lines fouling the prop shaft. The skeg that supports the rudder helps prevent issues with damage from groundings, but but semi-submerged driftwood could still be a problem. Luckily we don't cruise at 90 miles an hour, so that helps.

Here's a nifty combo shaft zinc anode & line cutter that might be worth looking into. Unfortunately for my boat there isn't room between the cutlass bearing & prop to fit this one.

https://www.youtube.com/watch?v=NVKNkCg5izM

[WillieC]

You can offset any drag from a cage by installing a bullet zinc on shaft. Maybe.

[NickScheuer]

I've seen the typical wire cage built around the 30" props in Main Lobster Boats. They do look like they do increase drag, however, Lobstermen are never bashful about adding more power by dropping in a larger engine, and increased drag would be a good reason to increase power.

I'm not interested in a larger engine than the MD17C we already have, and I'm not interested in slowing the boat either. So I guess I'm more interested in a ducted prop than a wire cage. A quick look at Kort Nozzles shows that they usually use special props with squared off tips that fit fairly close to the interior of the nozzle. That looks expensive. A true hydrodynamic nozzle looks very expensive.

I'm rapidly loosing interest.

[kerrye]

If you read thru the thread I linked, you'll see that apparently, Dave Laux was mistaken as the owner of the boat who had the cage installed said there was no noticeable drag induced by the cage. I'm now happier with my cage.