Loud noise when placed in foward gear

[AlanP]

Help
I have a 1982 C&C 30 Mk1, when I start the engine and place in forward gear there is a loud intermittent banging noise, does not seem to happen in reverse.
I removed the drive shaft and ran the motor in gear and did not hear it. I then pulled the drive shaft checked it for warp then replaced the stuffing box and checked the cutlass bearing all checked out fine.
Now I'm really worried.
Does anyone have any ideas what might be causing the noise? Do I pull the motor and do a tear down?
Regards
Alan

[ndutton]

What kind of prop do you have, folder?

[JOHN COOKSON]

Does the noise vary in pitch or loudness as the engine is revved up? On the surface, since the noise is absent in reverse, it sounds like something after the engine.

TRUE GRIT

[CalebD]

Looks to me as though the C&C 30 mk 1 has a strut securing the shaft under the boat. I suspect that the strut may be your problem as if that gets at all loose it will create noise/banging sounds.

http://sailboatdata.com/viewrecord.asp?class_id=1288

I suggest you not use the engine until this is checked out and fixed as this could create a leak below the waterline if it is really compromised. I was motoring on a C&C 35' mk 3 last summer and we heard a banging noise. Turned out that 1 of 4 bolts holding the strut in place had mysteriously disappeared leaving a nice 1/4" hole in the hull allowing water in that overwhelmed the pump on that boat. We got a tow and emergency haul out.

[sdemore]

My C&C 30 MK1 has a similar strut, but it isn't mounted in a hold chopped in the boat. I'm down in Mississippi for a funeral right now, but can post pics when I get back this weekend. This picture looks like a repair job done with a chainsaw, not a factory job.

[AlanP]

Loud noise....

Thanks for the response. I did try to move the strut back and forth by hand but it seemed solid. T
he prop is a two blade geared martec folder, the noise was also there with a fixed two blade.
The noise is intermittent I can hear low level clunking and when the revs increase the banging starts. At first I thought it was the reversing gear but was told different after checking out everything aft of the reversing gear I guess I'm back to that. I'll start at the bearing moving forward, looks like the motor needs to come out.
Regards
Alan

[Dave Neptune]

Alan, could the noise be coming from the "engine" or does it only happen in forward?

Dave Neptune

[JOHN COOKSON]

Are the motor mounts tight?

TRUE GRIT