I am renovating a 28 foot wooden double ended sailing boat.
The chain plates are screwed to the outside of the hull (stripped planked).
I would like to fasten the plates with bolts though the hull but this would
mean removing tidy looking ceiling and that in turn mean removing the
bulkheads, furniture etc.
There does not seem to be any problems with the screw fittings at the chain
plates but my question is, would i be wasting alot of time fastening the
plates with bolts instead?
thanks
neil

I'm surprised to hear of screws being use for chainplate on a boat of that
size..

IMHO you should go ahead with through bolts..

You can first drill from the outside with a long 1/4" pilot bit, coming all
the way through the ceiling. This will give you an accurate location. Then
take a large hole saw that you can handle and cut an access hole (don't go
too large, where the holes might over lap) in the ceiling material, all the
way to the hull planking (stop there).. Install a backing block as large as
you can fit into the access hole. Followed by the new chainplate bolts and a
large fender washer and standard washer and nut.. (I don't use nyloc or lock
washers, I just put a dab of 5200 on the theads.)

You can do a very neat job of plugging the access holes by turning some
nice hardwood plugs with a ridge to keep them from going in too far.. Secure
your plug in place with a dab of adhesive (you will want to check your bolts
periodically without destroying the plug).

Now you have a properly secured chain plate, with the proper fasteners that
can be inspected periodically.


--
My opinion and experience. FWIW

Steve
s/v Good Intentions

If there's no evidence that the existing fastenings have failed, i.e., if the
paint film where the chainplates join he hull shows no cracking, i'd let
sleeping dogs lie until a knowledgeable surveyor told me otherwise.

Neil wrote:

I am renovating a 28 foot wooden double ended sailing boat.
The chain plates are screwed to the outside of the hull (stripped planked).
I would like to fasten the plates with bolts though the hull but this would
mean removing tidy looking ceiling and that in turn mean removing the
bulkheads, furniture etc.
There does not seem to be any problems with the screw fittings at the chain
plates but my question is, would i be wasting alot of time fastening the
plates with bolts instead?
thanks
neil

I think Jim Conlin has the right take: If it aint broke, it may not need
fixing. If the boat was sailed about the same way you will so (or
harder) and the screws worked well, they'll work fine again, assuming
the materials haven't deteriorated. You can fill the existing holes
slightly with wood slivers and epoxy, drill them (correct size for
screws) again if needed, and re-install as the builder did it (using new
fasteners compatible with the chainplates).

Using a hole-saw from the inside to access the bolts might work OK, but:

1) Before you use the hole-saw, find if there is any stuff behind the
ceiling that you might not want to cut through (wires, hoses, frames).
Bend a coat hanger at 90* 3-6" from one end and stick it into the 1/4"
hole and rotate it in the cavity to see what it encounters.

2) If you put any 5200 on the threads, you might as well WELD the nut
onto the bolt - you won't be moving it again without lots of special
effort. This is not a good thing, since bolts have been known to need
re-tightening. Also, note that bolts can crush wood fiber and greatly
reduce it's strength. Get some advice before you crank down with a 3/4"
drive breaker bar.

Rufus

Neil wrote:

I am renovating a 28 foot wooden double ended sailing boat.
The chain plates are screwed to the outside of the hull (stripped planked).
I would like to fasten the plates with bolts though the hull but this would
mean removing tidy looking ceiling and that in turn mean removing the
bulkheads, furniture etc.
There does not seem to be any problems with the screw fittings at the chain
plates but my question is, would i be wasting alot of time fastening the
plates with bolts instead?
thanks
neil

There is no evidence of failure, the varnish around the plates looks fine.
It's just the idea of all that (apparent) weight pulling up against 11
screws. Even so, given the shape of the hull the pull on the rigging pulls
the bottom end of the plate partially against the hull.
Bolts would be better but I shall consider leaving the job to a later stage
in the renovation.
Many thanks for your replies
Neil