03/15/05

Pictures of old and new bobstay plate on LoBo, CT37 hull #20.

The old plate is 3/8" thick and was attached with two 3/8" bolts 
(standard SAE threads) through the hull into embedded nuts and 
(probably) some type of backing plate.  Because the nuts are 
fully embedded in the polyester resin casting in the forward 
lower section of the bow, they cannot be inspected without 
drilling out a lot of material on the inside of the chain 
locker.

The new plate is also 3/8" thick, but has "wings" that extend on 
both sides that are attached to the resin filled hull with three 
2 1/2" long 3/8" s/s lag bolts.  Through bolting from side to 
side would have been better, but I was concerned about hitting 
the original nuts / backing plate or the plastic drain pipe that 
runs from the bottom of the anchor locker down along the bow to 
the bilge  (it is also fully embedded in resin).  5/16" pilot 
holes were drilled for the bolts, and they were first inserted 
using soap as a lubricant to cut the threads into the resin.  
The bolts were then attached with polysulfide caulk in the 
holes.  The added wings and bolts are just a non-engineered belt 
and suspenders approach to adding a little more piece of mind 
because I can't inspect the original nuts and backing plates.

The new plate was bent from one piece of stainless steel.  A 
template made as a guide for the machinist from three 3/8" 
plywood pieces.  Some epoxy filler was needed between the hull 
and the new plate to ensure a tight fit.

The old plate had two tangs welded on to form a fork for the 
bobstay terminal end.  I had a 1/2" tang welded onto the new 
plate and used a Sta Lok fork fitting on the bobstay.  The new 
tang is also larger and has a second hole drilled in case I ever 
want to try using it as an anchor snubber.

A 1" PVC pipe was slid over the bobstay wire before attaching 
the new fork terminal end.  The pipe will serve as roller and 
chafe preventer for the anchor rode.

Chuck Snyder