A while back the rear beam on 1434 (Carter plywood boat) started creaking. So I checked the beam bolts and they were all loose; I tightened the bolts up and the creaking stopped... for a while. When the creaking started again I checked the bolts again; the port side were still tight but the starboard side had come loose so I tightened them again.

After that the starboard side bolts kept coming loose and I kept tightening them. The beam bolts have 1" square aluminium washers under the heads of the bolts and the washers have squashed the timber to the extent that they are now completely recessed into the timber. So I made some big 40mm x 75mm washers out of 3mm stainless to spread the load on the timber.

I fitted the washers yesterday and did the bolts up very tight, but the beam is still creaking. Does anyone have any ideas about what might be going on here?

Thanks,
Greg.