My understanding was that 737-400 and A320 do not require slide-rafts as per certification specification.
Different on -800 and A321. Indeed though, the Hudson A320 actually A/C had rafts, unlike most ours.
The "overwater" seems to relate to carriage of life vest as opposed to seatcushions only as flotation devices. IIRC Cactus had no life vests for PAX.
Last edited by FlightDetent; 4th December 2016 at 23:26.