Problem!!!

[surfingyetty]

Hi Guys,
I have just aquired an old hurrican 4.9 (I think) that needs some repaire, the first job is to remove the stubs of bolt left in after the cross bars were cut off but they are corroded solid into the metal plates they are screwed into, the bolts won't come out of the plate and they plate won't come out of the hulls. The only thing I can think of to do is to drill new holes about half an inch in from the onld ones then to file the old bolts flat, will this effect the strenght of the boat??

[Guest625101138]

Why not drill out the old bolts. Start with about 1/4" drill and then go up to the size that would be used for a tapping hole. You should only need to drill below the depth of the metal plate and then break the end off from the inside.

Making new bolt holes inside the existing ones will reduce rigidity a little because you are getting further away from the side of the hull that provides stiffness to the backing plate. Need to also check that the backing plate actually sits below the proposed holes.

For my mind drilling new holes would not be a lot less effort then simply drilling the old bolts out and running a tap though the holes.

Rick W

[surfingyetty]

We thought about it but drilling out solid 8mm bolts would take some time and the drill bit will have a tendancy to drift into the softer fiberglass.

[Guest625101138]

Originally Posted by surfingyetty

We thought about it but drilling out solid 8mm bolts would take some time and the drill bit will have a tendancy to drift into the softer fiberglass.

You can use the grinder to make the bolt flat and then centre punch it. Start with a smaller bit that is easier to control if you have concerns about slipping off. If you are really worried about sliding off then use a drill guide hole in a piece of scrap steel that can be clamped/strapped/butted securely in place with the guide hole on the centre of the bolt. You only need to drill below the depth of the backing plate not all the way through the stub of the bolt.

I would be putting a lot of effort into removing the old bolt rather than making new holes. Unless you have detail on the design of the connection you could create more problems by relocating the hole.

Rick W