Larger diameters or higher unit weights are feasible and are assembled in workshops located on water ways.
mandrel (cylindrical core) pre-fabricated with tube sheets on both sides, rotating on a winding bench
winding of tubes, layer by layer, using spacer bars (winding direction is changed for each tube layer)
wrapping into a shroud (avoiding any shell side by-pass flow)
tube to tube-sheet welding
assembly of the tube sheets with the pre-fabricated bonnets
insertion of the tube bundle into the pre-fabricated shell
completion of the shell with dished ends, nozzles, etc.
final testing & third party approval