Pioneering container ships

As well as being the first coasters be built post-war in America, the ships unwittingly heralded a new era in cargo transport through their use of containers. Unlike the later standardised shipping container, these ships were designed for rather smaller units – of 8ft 6in and 17ft length. They were designed to interlock together and carried in an unobstructed hold, while the upper deck would be used to transport cars, rather the reverse of later practice. Loading and discharging was carried out entirely on the ro-ro principle via stern doors, with the containers handled by fork lift trucks and special motor trucks, allowing a complete turn-around in port in less than 4.5 hours.

The ship design had to accommodate the loading arrangements, which meant that when half loaded all the cargo was stowed forward of amidships, so ‘trimming’ tanks were employed to maintain a level trim allowing the fork lift trucks to operate. In addition, a forced air system was provided to keep the cargo space free from condensation.

Two propellers were directly driven by a pair of eight-cylinder turbocharged Enterprise diesels each rated 2,100 bhp at 290 rpm. The engines were capable of running on Diesel oil or heavy fuel.