pot warp protection from wheel

[wtsawyer]

I'll be volunteering with the USCG Auxiliary this summer on Penobscot Bay, Maine when I head north from here in GA.
I'm very worried about lobster pot warps becomming wraped around my wheel. So far, the local Hinckley yard has proposed installing a well-known, rubber U-Joint to extend the shaft/wheel far enough beyond the keel's end for room for a set of "cutters". The added benefit would be quieter drive line noise as used on Flemings and other yachts.
I prefer the idea of extending the existing keel strap (about 5' long along the keel now) beyond the wheel so warps might simply "slide" off the end and miss the wheel.
Obviously, the wheel could be damaged by a bent strap in any heavy grounding, but I think the wheel's at risk in such a hard grounding without extending the strap in any event.
A second consideration would be to "close" the space between the keel, running under the wheel, and attaching the strap to the bottom of the bronze rudder at its pivot point. However, the same issue is raised about damaging the rudder in a hard grounding and I'm uncertain how to deal with dissimilar metals.
Question: Have you dealt with other's concerns about wraping pot warps around an unprotected wheel/shaft?
Care to share any thoughts on the "cutters" vs. extending the keel strap?
Thanks!
Cdr Tom Sawyer, USCG Auxiliary

 

[BobR]

I can't comment on the other options but I used a line cutter when I sailed out of Falmouth and it worked well.
They were fairly popular and probably the reason that fisherman finally stopped laying their traps in marked channels!

 

[knotflying]

I know the cutters work well, but can't comment on modification to the shaft and moving the prop back. Having cruised in Maine you definitely need to be diligent looking outside the boat while on the move. As an alternative, bring a wet suit and a sharp knife. 😀

 

[SGIDAVE]

Hello Tom,

You may be in luck...the "special" on Active Captain this week is the Shaft Shark at Defender (http://www.defender.com/activecaptain.jsp).

The "strap" you refer to may offer some propeller protection from objects struck from below but in a "hard" grounding would bend INTO the prop and cause trouble, possibly disabling your boat until you can bend it down/out of the prop.

Retrofitting a keel SHOE arrangement would offer better grounding protection, although I don't know how feasible this is with your Cutwater.

I personally doubt the the shoe arrangement will help with pot warps, however. When the prop is rotating, it generates water flow in such a manner that the warp will be drawn in from the sides so that the keel strap or shoe offers no effective protection. You can see this process in YouTube vids; search for "propeller line cutters" or similar.

Your installer has probably address this, but adding the flexible spacer to your transmission to extend the shaft further beyond the cutlass bearing (thus allowing shaft space to mount the line cutters) carries the risk of the shaft flexing due to increasing the unsupported length. My limited understanding here is that the unsupported shaft between the cutlass bearing and the hub of the prop not exceed ONE shaft diameter. Comments from other Cutwater owners indicate that the distance from cutlass bearing to prop hub is TOO small (so that the propeller CAN'T be removed with a conventional C-type puller), so creating more space there may help that situation as well.

Let us know what you end up installing. Are you looking to install the "Drivesaver" product?

David

 

[wtsawyer]

Thanks for everyone's help and guidance.

The Hinckley yard in Savannah convinced me to install line cutters just forward of the prop. We'll see just how this works out once we head back to Maine for the summer in July...

 

[mspaugy]

On the large ships that I work on "Spurs" line cutters are installed directly in front of the prop and they work very well.