Diving planes, also known as hydroplanes, are control surfaces found on a

submarine A submarine (often shortened to sub) is a watercraft capable of independent operation underwater. (It differs from a submersible, which has more limited underwater capability.) The term "submarine" is also sometimes used historically or infor ...

which allow the vessel to pitch its bow and stern up or down to assist in the process of submerging or surfacing the boat, as well as controlling depth when submerged.

Bow and stern planes

Diving planes are usually fitted in two pairs, the '' bow planes'' at the front of the submarine and the ''

stern The stern is the back or aft-most part of a ship or boat, technically defined as the area built up over the sternpost, extending upwards from the counter rail to the taffrail. The stern lies opposite the bow, the foremost part of a ship. O ...

planes'' at the rear. The stern planes function in much the same way as an aircraft's

elevator An elevator (American English) or lift (Commonwealth English) is a machine that vertically transports people or freight between levels. They are typically powered by electric motors that drive traction cables and counterweight systems suc ...

. As the planes are a long distance fore-and-aft from the hull's centre of buoyancy, they introduce a pitching moment.

Ballast tank A ballast tank is a Compartment (ship), compartment within a boat, ship or other floating structure that holds water, which is used as ballast to provide hydrostatic stability for a vessel, to reduce or control buoyancy, as in a submarine, to co ...

s within the submarine adjust buoyancy to be neutral, making the boat controllable. The position of the planes controls the pitch of the boat and, with the forward motion of the boat, this controls depth. If not carefully controlled, this could lead to a 'porpoising' motion whereby the planesman continually hunts for a stable combination of depth and pitch. For easier berthing close alongside a jetty, submarines have used folding bow planes that retracted alongside the hull. Earlier submarines (to World War II) used vertical-folding planes perpendicular to their surface. US submarines referred to this stowage as 'rigging' the planes, and 'tilting' for their control movement. Later Soviet submarines have tended to fold backwards, into recesses in the casing. HMS Ocelot 1962 side view of stern

Fairwater planes

Simon Lake Simon Lake (September 4, 1866 – June 23, 1945) was a Quaker American mechanical engineer and naval architect who obtained over two hundred patents for advances in naval design and competed with John Philip Holland to build the first submarines ...

of the Lake Torpedo Boat Company was the first to develop planes that could control depth without introducing a pitching moment. Stern planes and rudder were mounted below the stern akin to a conventional ship. The depth control planes were mounted on the beam, so that they acted vertically, without the lever arm to introduce the usual pitch. Diving planes located on the

sail A sail is a tensile structure, which is made from fabric or other membrane materials, that uses wind power to propel sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and even sail-powered land vehicles. Sails may b ...

(

conning tower A conning tower is a raised platform on a ship or submarine, often armoured, from which an officer in charge can conn (nautical), conn (conduct or control) the vessel, controlling movements of the ship by giving orders to those responsible for t ...

) are called fairwater planes on US Navy submarines. Fairwater planes do not pitch the ship up or down; they cause the boat to rise or sink on a level plane as they are operated. Defense

When operating beneath

polar ice A polar ice cap or polar cap is a high-latitude region of a planet, dwarf planet, or natural satellite that is covered in ice. There are no requirements with respect to size or composition for a body of ice to be termed a polar ice cap, nor a ...

, a submarine with planes on the sail must break them through the ice when surfacing. From the they were arranged to be able to be pointed vertically upwards, rather than being rigged or folded in. Newer boats, starting with the third-flight ''Los Angeles'' class subs (or 688is) have eliminated the sail planes, and operate instead with bow planes.

Controls

From the outset, diving planes were controlled remotely by

telemotor In mechanical and control engineering, a servomechanism (also called servo system, or simply servo) is a control system for the position and its time derivatives, such as velocity, of a mechanical system. It often includes a servomotor, and uses ...

s, early

servomechanism In mechanical and control engineering, a servomechanism (also called servo system, or simply servo) is a control system for the position and its time derivatives, such as velocity, of a mechanical system. It often includes a servomotor, and ...

s operated electrically or by hydraulics. Maintaining depth in a submarine is a sophisticated task. The planesman was provided with a prominent depth gauge to monitor this, usually a circular

Bourdon gauge Pressure measurement is the measurement of an applied force by a fluid (liquid or gas) on a surface. Pressure is typically measured in unit of measurement, units of force per unit of surface area. Many techniques have been developed for the me ...

. For precise maintenance at

periscope depth A periscope is an instrument for observation over, around or through an object, obstacle or condition that prevents direct line-of-sight observation from an observer's current position. In its simplest form, it consists of an outer case with ...

an additional shallow-depth

manometer Pressure measurement is the measurement of an applied force by a fluid (liquid or gas) on a surface. Pressure is typically measured in units of force per unit of surface area. Many techniques have been developed for the measurement of pressu ...

, a transparent vertical pipe, would be provided too. With the development of active sonar, depth control became even more complex. Rather than maintaining a simple depth, the planesman must now keep the boat beneath a

thermocline A thermocline (also known as the thermal layer or the metalimnion in lakes) is a distinct layer based on temperature within a large body of fluid (e.g. water, as in an ocean or lake; or air, e.g. an atmosphere) with a high gradient of distinct te ...

in order to hide from sonar. To this end, the helm position may also show external water thermometers and

salinometer A salinometer is a device designed to measure the salinity, or dissolved salt content, of a solution. Since the salinity affects both the electrical conductivity and the specific gravity of a solution, a salinometer often consist of an ec mete ...

s. Early submarines had separate controls for each pair of planes, bow and stern. Together with the

helmsman A helmsman or helm (sometimes driver or steersman) is a person who steering, steers a ship, sailboat, submarine, other type of maritime vessel, airship, or spacecraft. The rank and seniority of the helmsman may vary: on small vessels such as fis ...

, this required three

rating A rating is an evaluation or assessment of something, in terms of a metric (e.g. quality, quantity, a combination of both,...). Rating or rating system may also refer to: Business and economics * Credit rating, estimating the credit worthiness ...

s in the already-crowded control room. By the 1960s, combined controls were introduced. These incorporated all planes onto a single aircraft-style control wheel.

Cars

In automotive terms, dive planes (which physically resemble submarine diving planes) are

aerodynamic Aerodynamics () is the study of the motion of atmosphere of Earth, air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dynamics and its subfield of gas dynamics, and is an ...

devices fitted on cars just ahead of the front wheels. They are most commonly found on racing cars such as the

Le Mans Prototype A Le Mans Prototype (LMP) is a type of sports prototype race car used in various races and championships, including the 24 Hours of Le Mans, FIA World Endurance Championship, IMSA SportsCar Championship, European Le Mans Series, and Asian Le M ...

Series and are used to create additional downforce and channel airflow to help balance the car. The 2012 Mercedes-Benz C63 AMG Black Series is one of the first road cars to feature these devices.

References

{{reflist, colwidth=35em, refs= {{Cite book , title=Bow and Stern Plane Systems , work=The Fleet Type Submarine Training Manual , date=June 1946 , author=Bureau of Naval Personnel , ref={{harvid, Fleet Submarine , url=http://maritime.org/doc/fleetsub/hydr/chap5.htm#5A , pages=105–130 Submarine design Submarine components