SRB are simple steel tubes, filled with rubber to burn out a hole in the back.
These are true rocket engines (very, very high-speed, super-small clearance turbo-pumps at many tens of thousands of rpm pump cryogenic fuels and liquids, gyro’s, radio, controls, hydraulics .... You CAN’T land that in salt water.
Better fire up that 3-D printer. We’re gonna need another one.