Abstract: A retractable towing pin unit is provided for use on marine vessels as a guide for tow lines which extend overboard. The unit is designed to be installed in pairs on the deck of a marine vessel for centering the lines therebetween. The unit includes a pin mounted on a platform which is pivotable between a lower, inoperative position and an upper, operative position. An inflatable actuator device operable by pressurized air is mounted underneath the platform to raise and lower the pin between extended and retracted positions relative to the deck of the vessel. When not in use, the pin is safely retracted out of the way and flush with the deck.