Davit
Encyclopedia
A davit is a structure, usually made of steel, which is used to lower things over an edge of a long drop off such as lowering a maintenance trapeze
down a building or launching a lifeboat
over the side of a ship.
The development of the davit from its original "goose neck form" to the current devices advanced greatly when A.P. Schat patented a number of systems in 1926 that allowed the lifeboat to glide over obstructions on a ships hull known as the "Schat Skate". This was followed by a self-braking winch
system that allowed the lifeboat to be lowered evenly and then the modern davit was invented.
Davits have always been designed to fit into deck spaces that the naval architects deemed necessary and a variety of designs emerged:
The standard became so common that shipyard specifications call for Schat type davits from whatever source.
Davits can also refer to single mechanical arms with a winch for lowering life rafts and raising spare parts onto a vessel.
Recent developments are based on aft-launched ramps where the lifeboat is allowed to free fall, as opposed to being lowered by a winch, into the ocean. Thus its name, free fall lifeboat, is apparent. Similar systems developed by Schat companies are used on offshore oil/gas rigs placed around the structure.
Trapeze
A trapeze is a short horizontal bar hung by ropes or metal straps from a support. It is an aerial apparatus commonly found in circus performances...
down a building or launching a lifeboat
Lifeboat (shipboard)
A lifeboat is a small, rigid or inflatable watercraft carried for emergency evacuation in the event of a disaster aboard ship. In the military, a lifeboat may be referred to as a whaleboat, dinghy, or gig. The ship's tenders of cruise ships often double as lifeboats. Recreational sailors sometimes...
over the side of a ship.
The development of the davit from its original "goose neck form" to the current devices advanced greatly when A.P. Schat patented a number of systems in 1926 that allowed the lifeboat to glide over obstructions on a ships hull known as the "Schat Skate". This was followed by a self-braking winch
Winch
A winch is a mechanical device that is used to pull in or let out or otherwise adjust the "tension" of a rope or wire rope . In its simplest form it consists of a spool and attached hand crank. In larger forms, winches stand at the heart of machines as diverse as tow trucks, steam shovels and...
system that allowed the lifeboat to be lowered evenly and then the modern davit was invented.
Davits have always been designed to fit into deck spaces that the naval architects deemed necessary and a variety of designs emerged:
- GRA - Gravity roller track davit (Miranda) – usually above promenade decks.
- SPG - Single pivot gravity davit (Radial) – for many different deck spaces.
- FFD - Free fall davit – For free fall lifeboats on stern
- QD - Quadrantal davit – Old mechanical style, often hand cranked into outboard position
The standard became so common that shipyard specifications call for Schat type davits from whatever source.
Davits can also refer to single mechanical arms with a winch for lowering life rafts and raising spare parts onto a vessel.
Recent developments are based on aft-launched ramps where the lifeboat is allowed to free fall, as opposed to being lowered by a winch, into the ocean. Thus its name, free fall lifeboat, is apparent. Similar systems developed by Schat companies are used on offshore oil/gas rigs placed around the structure.