The 4 x 100m Swim and Tow is a traditional lifesaving event. The idea is that the competitors each swim 50m and pick up their team member from the wall. They then tow them, typically using an extended arm tow, 50m. Once they have touched the wall the person who was being towed then sets off and swims 5om to the next person and tows them. The team of 4 that completes the event in the quickest time wins.
The rules for this event can be found in the BULSCA Competition Manual.