People often use "float plane" and "seaplane" as if they mean the same thing. They are related, but not identical. Here is the difference, explained simply.

Float plane vs. flying boat: what's the difference?

Either type can be an amphibian if it also has wheels for runways. Float planes become amphibious with special floats that hold retractable wheels. Floats without wheels are called straight floats, and those aircraft can only operate from water.

Float plane characteristics

A float plane, also called a pontoon plane, sits on separate floats instead of wheels. Its fuselage is not meant to touch the water. Most float planes are land planes that have been converted, usually with two floats, sometimes with one large central float. This is the most common kind of seaplane, especially among smaller aircraft.

Floats share a few clever design features. Each float has a step, a break in the bottom profile. During take-off, the aircraft rises "onto the step" so less of the float is in the water, which cuts drag and lets it accelerate to flying speed. The top of the float is called the deck, and small water rudders at the back of the floats help the pilot steer on the water.

The shape of the float bottom matters too. A shallow V gets onto the step easily in calm water but gives a harder ride in waves. A deep V handles rough water better but needs more effort to break free in calm conditions.

Float plane pros and cons

• Simpler and cheaper: because the fuselage stays dry, it does not need to be watertight or built like a boat, and floats can be fitted to proven land aircraft.
• Easy docking: on most float planes the wings sit high above the water, clearing docks and making boarding easy.
• Quick take-off on smooth water: a skilled pilot can lift one float out of the water first to reduce drag.
• Trade-off in the air: floats add weight and drag, so a float plane flies a little slower and climbs more slowly than the same aircraft on wheels.

Flying boat characteristics

In a flying boat, the fuselage itself provides buoyancy. Its underside is shaped like a ship's hull, so water flows around it, and small floats under the wings keep it level. Most large seaplanes in history were flying boats, because a hull can support a great deal of weight.

Flying boat pros and cons

• Better in rough water: a strong hull and lower centre of gravity make flying boats more stable in waves.
• Size: the hull design works well for large aircraft.
• More demanding take-off: the whole hull must break free of the water, and poor technique can cause "porpoising", a dangerous bouncing motion.
• Complex to build: the fuselage must be watertight and strong enough for water landings.

Which is better, a float plane or a flying boat?

It depends on the job. Large flying boats suit rough open water and heavy loads. For connecting islands, resorts and lagoons with small groups of passengers, a float plane is hard to beat: it is simple, rugged and easy to board from a beach or dock.

One of the most famous float planes ever built is the de Havilland Canada DHC-2 Beaver, the aircraft Horizon Sun Charters flies from its base in Puerto Princesa, Palawan.

The de Havilland Canada DHC-2 Beaver float plane

Built in Canada as a rugged bush plane, the Beaver can operate from the sea, lakes and rivers with a water run of around 300 metres (1,000 feet). Flying under Visual Flight Rules, it carries up to around half a tonne across the islands of Palawan, ideal for a country of more than 7,000 islands where roads and ferries can take many hours.

• Seats: up to 6 passengers + 1 pilot (with luggage, we usually fly up to 4 guests per flight)
• Wingspan: 48 feet (14.6 m)
• Height on floats: about 10.4 feet
• Length on floats: about 32.9 feet
• Cruising speed: about 180 km/h

Questions people ask