The cat is a 4.4 metre Alpha Omega built by Darryl Barret in Adelaide, Australia. There were about 300 built in the 80's. I think Darryl has updated the moulds to produce his new F14. Access to the hulls is by pulling off a deck cover and then reglassing it, something i don't want to resort to just yet. from memory I think the problem bolt screws into a threaded bush and not a nut. Don't know about accessing it and not too keen either. I will unbolt the beam from the other hull and the main beam and try to reinsert the tramp after I re sew the bolt ropes.