Catapults in the modern (steam) sense are a British invention. Best reference book I've found for general naval aviation is title "Wings over the Sea" British author (can'tremember name,(book packed away) , global coverage Brit and US emphasis but lots of other good stuff.
No catapults in regular use on US carriers until very late/after WW II.
The armed merchantmen CAM aircraft were almost completly Hurricanes and all missions were one way unless a carrier or airfield was within range (in which case why launch the CAM Hurricane). The catapult was rocket powered and produced by the MoD department that employed Nevil Schute and other "inovative" folks.