An assembly for towing a boat (10) includes a pair of channel members (16, 18) mounted on the transom (14) of the boat and a towing socket (50) formed as part of an upstanding hitch (54) carried on a tow vehicle. A pair of leaf spring supports (20, 22) each carry wheels (44, 46) and stub axles (40, 42) and are pinned to the channel members by means of pivot pins (24, 26) and other removable pins (36, 38) which hold the supports firmly in the channels when the removable pins are in place, which holds the wheels firmly in the lowered position for towing and which permit the supports and wheels to be rotated around the pivot pins to store the wheels when the removable pins are removed. Each of the stub axles includes a hollow extension (40, 42) which supports at its outboard end a rod or shaft (48) serving as a stabilizing bar and the stabilizing bars are held in axial alignment by means of a stabilizing retaining tube (62) supporting the stabilizing bars at their inboard ends.