Grinding, Scraping, Metal-on-Metal Noise?

[Baron69R]

The other day I was on a short bay cruise, and when I turned around and put it in idle forward, a grinding, scraping, metal-on-metal noise came from what seemed to be the starboard side about mid-ship. The noise would stop after a few seconds and all seemed fine. This continued thru docking, every time I put the boat in forward the noise would start and last a few seconds then stop. I don’t want to move the boat until I can figure out what it is and have a mechanic look at it. Any ideas of where to start troubling shooting and what to look at with something like this? Could it be the transmission, bearings, something in propeller shaft seals...? Any help or ideas appreciated.

[km1125]

You should include what year/model boat you have and what engines/transmissions are in it.

You should have someone observe the engine/transmission and prop shaft (inside) while someone is putting it into gear to see if there's something obvious moving that shouldn't be.

[bud37]

Welcome to the forum.....do you have a diver to see if you picked up something around the prop shafts etc.

Remember no swimming in a marina, too dangerous due to the possibility of electrocution hazards being present....certified divers have the experience and safety knowledge to do this safely, or should have.

[Baron69R]

Boat is a 2004 59 Marquis with Twin Disc transmissions. Took Bud37's advice and had my diver look around at running gear, zincs, etc. Everything was secure.

KM, "You should have someone observe the engine/transmission and prop shaft (inside) while someone is putting it into gear to see if there's something obvious moving that shouldn't be.". Working on this. Will get a mechanic to listen and see if he can determine what's going on. Thank you.

[Baron69R]

Noise Update: One thing we found was that lubrication water line to my PSS Type A Shaft Seal was mounted so the hose was attached on the bottom of the carbon flange, putting a kink the hose. Accordingly, water was not properly lubricating, which caused it to squeal, which is what I heard. The position of the hose barb and hose for the one on the other side is mounted on the top of the flange, with no hose kinks. This all seems bizarre. Why would anyone install the hose like this or is it possible that it could have rotated to this bottom position on its own somehow...? In any case, can I simply rotate the carbon stator so that the hose is feeding water from the top? Could this be done without being hauled? I've heard nightmare stories of water flooding boats when these PSS-type seals foul or are messed with... Any experiences to share or comments appreciated. (photos attached)

[Viper]

On the top or the side is fine. You can loosen that part just enough to rotate it, it might take some strength to crack it free. The flange against it will prevent it from moving forward. Don't loosen the flange as that keeps the bellows compressed which is a must.

[Baron69R]

Thanks for the response, Viper. I'm going to give it a shot. I hear what you are saying about not loosening the flange that keeps the bellows compressed. I'll try rotating the carbon stator. May have to loosen the strap holding it in place. Thanks again.