The Naiad Voyages

Mark Austen

2022.11.25 - Task 4 Starboard Aft Chainplate

This morning was taken up with various chores but it was a lovely sunny day, albeit cool, so I made a start on the chain plates once the chores were completed.

The old chain plate was unbolted and unscrewed and the slot in the rubbing strake widened.

The new chain plate is quite a lot bigger than the old one, but that's the whole idea.

The new and the old to show the size difference on the boat.

The top hole was drilled first for the screw into the beam shelf and the chain plate dry fitted.

I'll have to bit of work cleaning up the hull as you can see, the old backing pad was epoxied in place and the plywood backing pad didn't come off cleanly.

Using the old chain plate as a template two more holes were drilled in the new plate and dry fitted again. The position of the bottom hole is not critical so it does not have to be in the exact position that the other holes should be.

A hole was drilled into the bottom of the first chain plate and then into the others using the first as a template.

The first chain plate was screwed into place and the bolts put in through the holes but the nut on the inside was not put on and the new hole in the hull drilled.

This is how the chainplate will look.

There are two more things to be done before the plate can be fixed. The first is to make a new backing pad to fit behind the new chain plate. The gap you can just see above is an odd shape but that gap really needs to be filled. I'll either use some hardwood to do this or some thickened epoxy. The wood is going to be quite hard to do as the pad needs to taper to a feather edge. On the other hand, epoxy is going to be messy and thin plastic will need to be put on the hull and the chain plate to prevent the epoxy from bonding where it shouldn't. I think I'll try the wood pads first and if that proves to be excessively difficult then I'll resort to the epoxy.

The second thing is to make a new backing pad for the inside. Ideally this should be bronze like the bolts and nuts, but bronze flat bar is currently very expensive so I'll probably go for 316 Stainless Steel which is about a quarter of the price. The stainless and bronze will have a thin layer of plastic or similar between them to prevent any galvanic corrosion. It shouldn't be a problem anyway since there will not be an electrolyte (such as water) between them but the nuts are in a very awkward place and inspection will be difficult. The plastic washer should prevent the problem entirely.