Test first with templates
This was one of those onboard installation jobs where I decided that it would be time well spent to make up a couple of simple templates to help me visualise how the ladder frame would sit, particularly in relation to the angle of the transom and the clearance required under the swim platform frame.
Plywood templates were made up to replicate the frame top and sides. These included the frame’s pre-drilled fixing points so by using these I’d be able to see clearly how things would best line up.
In fact once on the boat the templates showed that although two of the predrilled frame holes would line up well, the other two would fall in unsuitable positions on the swim platform. Holes for M6 nuts and bolts too close to the edge of the timber slats would make them vulnerable to splitting away.
The most practical solution, then, would be to drill new holes in the frame itself to provide alternative fixing points each side – and of course I could do this in the workshop at home.