U.S. ships in World War II had ‘phantom decks’

While the U.S. was lucky to fight World War II away from its shores, that meant it had to move massive amounts of supplies across the ocean. That meant some serious logistics came into play. It also meant that we had to constantly plan for contingencies. With German submarines sinking American vessels and shipyards busy rebuilding the fleet after the Pearl Harbor attacks, America needed a creative way to pack as much gear on each ship as it could. So we made up the idea of creating "phantom decks." 

Well, these ingenious decks just might've helped America win the way. The "phantom deck," also known as a "skeleton" or "Meccano" deck was developed by West Side Iron Works. Deck frames were built on top of normal decks so vessels could carry up to 10% more cargo. The decks were normally about 8 feet above the original top deck. In some cases, they could be as high as 15 feet. Separate platforms were bolted to holders to make the deck, and pad eyes were welded on so that cargo could be tied down.

West Side Iron Works knew these platforms had to be out of harms' reach. Buit they also knew a thing or two about physics. The heavier the vessel, the lower it will ride. So WSIW decided to build the platforms really high. This meant that if waves crashed across the top deck, the secret cargo wouldn't get damaged. 

The ingenious modifications were originally introduced on normal cargo ships. But WSIW and the world quickly realized they had practical applications for everyone. Soon, they eventually were fitted onto tankers and any other large vessels making the trip across the ocean. The platforms and pad eyes could be quickly removed if the ship needed to be reconfigured or the platforms were needed on another vessel.

Tankers were generally kept in the center of a convoy so that they were better protected. So, additional cargo space on those ships was especially valuable.

More than 600 tankers received these false top decks and shipped over 20,000 aircraft to Britain in the final years of the war.

Because of the saltwater, vehicles and planes on these false decks had to be coated with heavy lubricants. These thick materials and chemicals helped prevent corrosion. But before the Army learned this lesson, many of the tanks that arrived in the theater needed extensive work to remove rust before they were fit for service. When the war ended, the need for phantom decks subsided and the temporary innovations were removed.

Related: Check out this list of 7 things you probably don't know about the D-Day invasion.