Richard Quest, a CNN business commentator and aviation analyst, asked me, “What is the difference between a floatplane and a seaplane?”
Richard explained that on a newscast, he called an airplane on floats a seaplane, and the know-it-alls bombarded him with comments saying he got it wrong. My answer is an attempt to explain the difference and prove that the aviation analyst was, in this instance, correct.
Let’s first get the boring shit out of the way and work through the technical definitions. Since dictionaries often get this wrong, I will get an actual know-it-all (me) to handle the definitions. We must also include the term “flying boat” if I am to answer Richard’s question fully.
My Definitions:
Landings: This happens when a pilot returns an airplane to Earth on land or water. Landing is an essential part of flying. For a pilot, it is equally important that the total number of PIC and SIC landings equal the number of take-offs. If they don’t, that means you are airborne. To balance the books, you must land. A pilot once ran out of gas and jumped out of his airplane into Lake Ontario while airborne. The plane proceeded to land safely at the Billy Bishop airport without him. The authorities charged the culprit, and he went to jail. True story.
Alighting: Although most landings happen on land, some landings happen on water. To take the “land” out of “landing on water,” the Aussies better described the procedure of landing on water as alighting. Record “alighting” in the seaplane column of your logbook only if the airplane is designed to land on water. Sully’s landing on the Hudson doesn’t count, but at least he didn’t jump.
Gear: This is the undercarriage structure, including the wheels for landing on land or the pontoons for landing on water, allowing you to land safely. Without landing gear, the pilot might consider staying up there for a while, or at least until they remember they are not allowed to jump.
When landing on runways, the standard is to use fixed gear with wheels (Cessna C208 Caravan) or retractable gear with wheels (Pilatus PC12). For landing on water, the standard is floats with or without retractable gear or a hull with or without retractable gear.
Floatplane: A floatplane is a converted fixed-wing airplane that can float. It would have two pontoons (together known as floats) fixed as an undercarriage for taking off and landing (or alighting) on water. The pontoon design, much the same as a speedboat, has a watertight planing hull capable of creating buoyancy (displacement) when resting on water and hydrodynamic lift when taking off and landing on water. Examples include the Piper Cub, Citabria, Husky, Cessna C208, Norseman, Beaver, Otter, Beech 18 and the Viking Twin Otter.
Norseman Noorduyn Floatplane taking off from a lake in Canada.
Flying Boat: A fixed-wing airplane with a waterproof fuselage built into the shape of a hull capable of creating buoyancy when resting on water and hydrodynamic lift when taking off and landing on water. Examples of flying boats are the Consolidated Commodore, Sikorsky S-40, Short Empire, Martin M-130, Boeing B-314 and the Spruce Goose H-2. Flying boats have no landing gear and thus can only alight on water.
(Flying boats with landing gear are true Amphibians, but more about those later.)
Pan American Airways began international air travel in the 1920s using the Martin M-130 to connect the world’s oceans without airways or airports.
So, what is the fundamental difference between a floatplane and a flying boat? A floatplane can have the pontoons (the floats) removed and replaced with fixed landing gear, but afterwards, the airplane can only take off or land on land. You cannot reconfigure a flying boat as a landplane only; it is built to fly and float.
If it flies like a duck and waddles on water like a duck on land, it is a floatplane. If it flies like a duck and swims like a duck, it is a flying boat. If it flies like a duck, swims like a duck, walks like a duck, and quacks like a duck, then, fuck it, it’s a duck.
So, what, then, is a seaplane?
Seaplane: By the general definition, and to prove Richard Quest correct, a seaplane is any fixed-wing aircraft that can take off and land on water. The definition of a seaplane is the same as the French for Hydravion. There is no difference between a floatplane and a seaplane for the practical purposes of alighting. By the same token, there is no practical distinction between using the term flying boat or seaplane.
No flying boat is a floatplane. No floatplane is a flying boat. All floatplanes can be seaplanes. All flying boats can be seaplanes. Not all seaplanes are floatplanes, as not all seaplanes are flying boats. I suck at syllogisms, but I am awesome at alliteration.
Therefore, you can interchange the term seaplane for a floatplane or a flying boat. You can safely refer to a Martin Mars, Short Sunderland, PBY Catalina, Beaver, Cessna 185, Twin Otter, Cessna Caravan, Daher Kodiak, or a Douglas DC-3 as a seaplane as long as they are configured to take off and land on water. The US Airways Airbus A320, which landed on the Hudson River, cannot meet the criteria to be considered a seaplane as it lacked the design and capabilities for water landings and takeoffs.
DHC6-300 Series Twin Otter on Wipline Floats in the Maldives
Having said all that, Textron, Daher, and DeHavilland do not manufacture the Caravan, Kodiak, and Twin Otter as seaplanes. Take it from someone who has flown all these aircraft in both configurations; they are much better landplanes than seaplanes. Flying boats are (or damn well should be) designed as seaplanes. Remember the duck?
By my definition of a seaplane, however, there is a distinction beyond the technical configuration of a floatplane or flying boat. A seaplane also has to operate safely and efficiently on the sea. According to international law, all the ocean is a sea. The overall definition of the term sea, however, not only defines a large body of salty water, such as the Adriatic Sea or the Atlantic Ocean but, as an adjective, it also describes the surface condition of the sea or what is called the sea state. Whether the surface is calm, rough, heaving or confused is relevant to a seaplane operator. To operate safely, it is crucial to have a basic understanding of how to determine sea states.
Now, enough about the damn duck.
Next: Seaplanes and Seastates – Why When the World’s My Oyster
