When we talk about rafting up (small or big modules) we are basicly talking about assembling precast concrete elements to a bigger structure.
I have always been a fan of looking around in standard engineering what kind of solutions you see there for similar tasks. Obviously none of the structures that are around us (buildings, bridges, columns, dams, tunnels, etc) are built in one piece and then sent by truck to their location. But a astonishing big number of structures is built in precast facilities in pieces of truckload size and then assembled on the building site to structures that weight thousands of tons.
Bolting things together or magnets are not among the “frequently seen solutions” on structural concrete building sites. So i will not dismiss the possibility but i assume that this is so for good reasons. The techniques you frequently see on building sites to put precast elements togeher are:
Cast joints, post tension, grouting, epoxi bonding.
I see no reason why we should go away from that established way to do things just because we build on the water. Especially when each of the mentioned methods deliver a perfectly long term sal****er resistant joint (which is not the case with bolts).
