it's like this: bring it out onto knee-deep water, climb inside and paddle laterally.
in fact, most Korean beach activity happens 50 m from the shoreline. one occasionally sees one of those nutty swimmers a couple hundred meters in, but not without frenzied whistlings-down from the lifeguards. go back! it's above the torso!
this could be interpreted as a legitimate need for some safe activity, due to all the other extremely unsafe goings-on (e.g. annual mountain-burning; weeknight drinking parties).