Amphibious boats are watercraft fitted with retractable wheel or track systems that allow them to transit from water to land and back without a trailer, slipway crane, or launch ramp. They operate as conventional motorboats on water and as slow-moving wheeled vehicles on land, with the propulsion systems for each medium typically separate and independent.
The practical application is access to beaches, tidal zones, and remote shorelines where dock infrastructure does not exist and a conventional boat would ground before reaching dry land. Rescue services, tour operators, and superyacht owners operating in remote island or coastal environments use amphibious designs for this reason. On water, wheel assemblies retract or lift clear of the hull to reduce drag, and the boat operates via outboard, inboard, or waterjet propulsion. On land, motorised wheels — sometimes with four-wheel drive — move the hull at low speed across sand, rock, or gentle terrain. Suspension systems vary from basic rigid mounts to full independent suspension on higher-specification builds.
Hulls are aluminium or GRP, kept as light as possible given the additional weight of the wheel or track systems. The mechanical complexity of maintaining two independent propulsion systems — marine and terrestrial — results in higher purchase prices and greater maintenance requirements than conventional tenders of equivalent size. Regulatory classification is not straightforward in all jurisdictions, as the vehicle straddles maritime and road-vehicle certification categories.
