J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Too Many Holes

It occurs to me that the load case on these bolts for the clutches and winches is somewhat different than on many other elements on these composite hulls. There are a great many cases where the simple drill and fill approach is totally adequate for the situation, but there are two places that I think need a more advanced approach, clutches and the winches come quickly to mind. These items have very large lateral forces that are trying to pull the bolts sideways. Drilling and filling provides the required solution for the compression that comes with bolting and screws, but the bolt even with a large barrel of epoxy around it is then resisting the lateral force at the joint with the outside skin and the bearing against the balsa core, which is crazy soft in this load direction. The bolt and barrel of epoxy will try to essentially rotate or pivot about the opening of the inner skin (unless it too tries to fail). The critical junction in this arrangement is the bond between the epoxy barrel and the outer skin. The epoxy barrel won't compress, but it will try to pivot and likely crack the bond between the epoxy barrel and the skin. The larger the epoxy barrel the stronger it would be, but adding a layer of glass over the barrel and the skin would go a very long way to sharing the lateral load of the barrel to the skin.

Please excuse my drawing below