Why firms valued retired senior officers

Did shipyards use retired admirals as consultants for their connections or for their design knowledge?

Probably both; they combined relevant expertise with the contacts needed to put a product before the right officials.

Shipyards and arms firms valued retired officers for their knowledge and contacts. A former flag officer understood the service's requirements and could identify the officials or departments that needed to see a proposed product. Those relationships could move an idea into the right development or procurement channel without guaranteeing adoption. Formal retirement therefore did not end an officer's influence on acquisition.