How sectional floating dry docks joined at sea

How did US floating-dry-dock sections connect, and how calm did the weather need to be?

They had to be maneuvered by tugs so their interfaces meshed within carefully chosen tolerances, and the operation required stable, calm water.

Floating-dock sections needed controlled positioning so their connections could mesh. The proposed explanation depends on engineering tolerances: enough clearance to accommodate movement, with a close enough fit to secure the assembled structure. The sections had no propulsion of their own, so tugs supplied the movement. Calm water was essential for that positioning. This general engineering explanation does not establish the details of the particular US dock fittings.