Bradner and Bascom were not overly interested in profiting from their design and were unable to successfully market a version to the public. They attempted to patent their neoprene wetsuit design, but their application was rejected because the design was viewed as too similar to a flight suit. The United States Navy also turned down Bradner's and Bascom's offer to supply its swimmers and frogmen with the new wetsuits due to concerns that the gas in the neoprene component of the suits might make it easier for naval divers to be detected by underwater sonar. The first written documentation of Bradner's invention was in a letter to Marshall, dated June 21, 1951.