Fouled prop..Ticking and knocking gearbox.

[Mo]

Yesterday while sailing I noticed a ticking coming from under the cockpit floor. I opened the lazarette and noticed that while my shaft was turning there was a ticking noise coming from the reversing gear. I often feather the prop when in heavy wind to see how fast I can make her go.

The boat was sailing and I had it in neutral. Then put it in forward and it went away, same for reverse. At this point I fired up the engine and put it in forward gear....no problem. Put it in reverse and a loud banging from under the cockpit that stopped after about 5 seconds.

Brought the boat back to the dock under power with no loss of power or racket in forward. Going into my dock with 20 kts of wind on my stern (all the other boats are out here so nothing blocking the wind), I put it in reverse and got the knocking for the 5 secs ..but a good reverse.

First thing that came to mind was a fouled prop but I had good speed sailing and in gear. It did sound like it came from within the gear box, although, I know drive line noise can travel and be very tricky to dx.

Before I rip the thing apart I figured I'd call MMI. Spoke to Don Moyer and he figured there should be nothing in the gear box / reversing gear to cause a knock like I was describing. I had no noise with the engine in neutral idling. Don figured it must be in the shaft, cutless bearing, fouled or whatever. It would have to be seen.... I told Don I'd get a diver to have a look this morning.

Diver came and there was a cable wrapped around my shaft and it would unravel a bit but he couldn't undo the thing. I figured the boat is coming out this coming weekend so a few days earlier won't matter much....of course I was going for a last sail though...fouled prop or not.

Went for the sail in 20+ kts of wind (again today) and while sailing this cable was on my mind...how did it get there, how could it wrap without me hearing it at the time it got on there etc. The biggest question was why wouldn't it unravel.

So, here I am going along at about 6.4 kts and decide to fire up the engine and put it in reverse. I did it....the boat slowed a couple of knots and I throttled her up....continued like that for about 1 minute. Keep in mind the boat is still sailing about 4 kts with the engine in reverse.

The cable came off...it is gone. Don`t know what made me think of trying that but the drag of it must have helped with the turning prop.

Maybe that will help someone out sometime.

[Carl-T705]

Hi Mo, I guess the question is why couldn't the diver remove the cable when your engine reversing was able to sling it off. Here's hoping for no hull damage repair to ad to the off season work.

[ndutton]

A disadvantage the diver has is he's weightless, like working in space. Pull one way and you drift the other, there's no leverage. There may be something to grab for stability but still it's arm strength only, the body is floating all over the place.

I tried clearing a fouled prop (backed over the dinghy painter) on a friend's boat years ago. Forget it, bring on the knife.

[Mo]

When I pulled the boat on Sunday Oct 28 there was nothing on the prop....the shaft was shined bare from cable though.