The mini digger he was driving toppled into Crown Wharf in Castletown at low-tide on Saturday afternoon leaving the half-submerged machine resting on its side on the seabed.
Emergency services had to race against an incoming tide to free the trapped operator before a coastguard helicopter winched him to safety and airlifted him to a hospital in Southampton.
Eye-witnesses said the man was lucky not to have been crushed in the fall.
He suffered from serious but not life threatening injuries including a broken leg.