Probably where they got the idea to launch there vipers by catapult from the side.Infact this was done on USS-Essex(CV-9) in 1943 having a catapult from the hanger deck on her port side.It was also installed on most of her sister ships, but only Essex retained the catapult untill the end of the war.
For the pilots this was not an easy take-off as they often faced a 35 Knot side wind!





Regards Duggy.