Why building in a dry dock eases launch stresses

How does dry-dock construction affect the practical size of a ship?

It provides a gentler launch by flooding around the hull, avoiding some of the stresses imposed by a slipway launch.

Dry-dock construction allows water to rise around the completed hull until it floats. A slipway launch instead accelerates the ship into the water and changes how the structure is supported during the movement. Flooding the dock therefore avoids many dynamic loads and collision risks. With a sufficiently large dock, that gentler process makes a larger or heavier hull more manageable.