Definition of sponson in English:



  • 1A projection on the side of a boat, ship, or seaplane.

    • ‘The battery door is on the aft end of the sponson that houses the port main landing gear.’
    • ‘A 15-man life raft is installed either side in the forward section of each sponson.’
    • ‘The main units retract into the rear of the sponsons.’
    • ‘BAE Systems at Scotstoun, the shipbuilders, were subcontracted to build new bridge wings and sponsons, which were delivered to Portsmouth by road on the Friday before Christmas.’
    • ‘She struck the frigate, buckling the port 30 mm gun deck, crushing the sea-boat sponsons and damaging the bridge wing.’
    • ‘Wreckage was littered over a wide area of the lake surface and included Bluebird's twin sponsons, which had been torn away from the main hull.’
    • ‘The helicopter can be fitted with gun pods, rocket launchers and air-to-air missiles attached to two removable weapons sponsons.’
    • ‘He said: ‘The starboard sponson had lifted a foot out of the water and the craft was rolling heavily.’’
    • ‘At one critical point in the match, a streaker emerged from the hangar, running across the flight deck (in just shorts and hat), disappearing down onto one of the aft sponsons.’
    • ‘The main fuel tanks, with a capacity of 2,539 litres, are installed under the floor of the cabin and in the lateral sponsons.’
    • ‘The crew chief was underneath the starboard sponson, trying to unseat the landing-gear pin, when my copilot released the brakes.’
    • ‘The cartridge-activated device did not fire immediately, but by the time it did, the hoist cable was under tension from the parachute, making the cable hit the right sponson as the cable separated.’
    • ‘Indeed, lockers in the bow-deck and the sponsons themselves are possible, as is any arrangement of seating.’
    • ‘He said: ‘You can see the sponsons rock in and out of the water.’’
    • ‘The three davits for the deployment of landing craft and the patrol boat are relocated to a sponson installed on the port side of the ship instead of on the flight deck.’
    • ‘The enlarged sponsons provide additional stowage for carrying extra fuel, life rafts, floats or other equipment.’
    • ‘A key issue is the cleanliness of the hangar bay, sponson and door light-locker.’
    1. 1.1 A gun platform standing out from a warship's side.
      • ‘By Christmas the new bridge wing, gun deck and other sponsons had been replaced, and shortly after all the wiring and ship's fittings were replaced and set to work.’
    2. 1.2 A short subsidiary wing that serves to stabilize a seaplane.
    3. 1.3 A buoyancy chamber fitted to a boat's hull, especially on a canoe.
    4. 1.4 A triangular platform supporting the wheel on a paddle steamer.


Mid 19th century: of unknown origin.