I wanted to join the blocks, have them strong as people will be treading on them and have them removable AND use them to help secure the landing brake box AND let them be round so the ferry tank can rest on them AND have the ferry pumps down there too at the same height.
All I need for all that is a piece of aluminium to join them up. I haven't glassed the bottoms yet on purpose. I floxed and then glassed them in place in the usual careful processes. The aluminium was drilled and countersunk and all that good stuff.
The results are pics 2 and 3. Very solid foot rests that are not very heavy.