In the 1950's, PBI contracted with the US Navy to build MSB's, the first of what would become a long line of minesweepers built in Sturgeon Bay, Wisconsin. It was with the construction of these primarily wooden minesweepers that PBI got its first experience with aluminum construction. Many present day welding techniques were developed building aluminum fabrications for wooden ships. Working with Kaiser, Alcoa and Reynolds aluminum companies and major welding equipment firms of the time, PBI played an important role in the refinement of aluminum welding technology.

With the advent of the Korean War, the need arose for mine warfare craft - ships that were well suited to PBI's wood hull construction experience. During the 50's, PBI built many such craft for the US and foreign navies, including nine ocean going minesweepers (MSO's) ranging from 165' to 192' and five 57' MSB's. PBI also built a number of smaller craft including work boats, rescue craft and crew boats of both wood and steel construction.