How William the Conqueror assembled an invasion fleet quickly

How did William the Conqueror build the fleet for the invasion of England in such a short time?

Matilda organized much of the effort, Norman access to Viking-derived shipbuilding helped, and the vessels were built to make the Channel crossing rather than to serve for decades.

William's wife Matilda organized much of the fleet and secured a capable shipbuilder. Norman familiarity with Scandinavian seafaring traditions also made a rapid program more plausible. These ships did not need the durability expected of a standing navy; they primarily had to carry the invasion force across the Channel. That limited design purpose accelerated construction, although it also made the expedition more dependent on suitable weather. Medieval amphibious logistics depended as much on administration and acceptable service life as on ship count.