Naval treaties contracted the shipbuilding workload

Did the Washington and London naval treaties contribute to the decline of shipbuilding?

Yes; by limiting construction, the treaties directly reduced the volume of naval shipbuilding work.

The Washington and London treaty systems contributed to shipbuilding contraction by sharply reducing the number of ships ordered. Arms limitation affected fleet totals, the continuity of shipyard work, and industrial demand. Treaty policy therefore shaped the later condition of the naval industrial base.