During the summer, every time I looked across the companion way hatch the rusty screw heads on the hatch would wind me up. Any fastener on a boat should be stainless as all other metals will just dissolve or go furry. Fortunately I had the good sense to leave well alone until the end of the season.
It was a real struggle to get these apart without damaging the fibre glass. The sliders are a mixture of what looks like perspex and Tufnol* so have probably been replaced at some time in the past. Also born out by the saw marks on the GRP around the screw heads. What I need to know now is, is there an off the self replacement for these or do I need to fabricate new ones. And if so what out off? Tufnol, Acetal, Aluminium or something else. The runners are aluminium so I'm assuming they will need to be made of something softer. The bolts will certainly have to be A4 Stainless.
These are the drawings for the forward sliders. The rear sliders a 53mm in length but have the same pitch for the screw holes. I have found a 10mm ali plate in the garage, that I used to repair my mast foot, so I will probably make some out of that. I have included a recess at the end of each screw hole for the nut to fit into but if I am going to use the Ali plate then I will just tap a tread into the plate. I'll let you know how I get on... otherwise I'll go back to Papillon's plan, which is probably better.
Just to prove that I have been doing something constructive, rather than just watching sunsets and poking around washed up boats, here are my new sliders.
In the end I made them from the aluminium plate that I had in the garage. It was 10mm thick so, using a hacksaw, I cut some strips a bit wider than required. I then cut the strips to length and then carefully cut the edges out. A massive amount of filing and fettling followed. It took about five hours to make these four so quite a lot of time for something that won't be seen but that's just the way it goes. :~))
All I need to do now is drill and tap the screw holes and refit the hatch."
* Not sure about this... mine are/were made of the exact same stuff - which means they may be original and must have lasted for getting on 30 years....
I went the easier route and fabricated mine from a couple of these..