Seamanship
Seamanship is the art, competence, and knowledge of operating a ship, boat or other craft on water. The Oxford Dictionary states that seamanship is "The skill, techniques, or practice of handling a ship or boat at sea."
It involves topics and development of specialised skills, including navigation and international maritime law and regulatory knowledge; weather, meteorology and forecasting; watchkeeping; ship-handling and small boat handling; operation of deck equipment, anchors and cables; ropework and line handling; communications; sailing; engines; execution of evolutions such as towing; cargo handling equipment, dangerous cargoes and cargo storage; dealing with emergencies; survival at sea and search and rescue; and fire fighting.
The degree of knowledge needed within these areas is dependent upon the nature of the work and the type of vessel employed by a seafarer.
History
Before the 1600s, Seamanship skills were taught by hands-on instruction, after the 1600s, and 1700s, seamanship started being taught by literature.Ship knowledge, ship stability and cargo operations
Seamanship on a commercial level involves a knowledge of all the different ship types, including a basic knowledge of ship recognition, a basic understanding of nautical terms, ship structure and naval architecture and cargo operations, specific to the vessel the seafarer is working on. Some ship types will have specialist cargo equipment and tools; for example, a bulk carrier may have gantry cranes or grabs for cargo or a container ship may have container lashings. Cargoes should be properly stowed and secured to prevent shifting while at sea. Oil tankers and gas carriers can be somewhat complex due to the hazardous nature of their cargoes, and therefore a greater degree of seamanship may be necessary for some vessel types compared to others.Seamanship involves paying close attention to the stability of the vessel at all times. This involves calculation of the vessel and the effects of its cargo at various stages of the voyage to allow for safe passage and prevent capsizing. This includes familiarity and application of the Load Line Convention, where a vessel can only be safely loaded to its markings to ensure residual stability for the likely weather conditions. Seafarers should regularly inspect their vessel and ensure the hull is in good condition for navigation.
Seamanship skills apply to the safe use of different types of lifting gear, whether for cargo operations or for bringing on stores, supplies and provisions. These example Derricks, Union purchase arrangements, midship or aft cranes, heavy lifting gear, rigging other sheer legs etc. This should include knowledge of calculations of stresses and effects on stability.
Navigation
Navigation is the art and science of safely and efficiently directing the movements of a vessel from one point to another. Piloting uses water depth and visible references, while dead reckoning uses courses and distances from the last known position. More than just finding a vessel's present location, safe navigation includes predicting future location, route planning and collision avoidance. Nautical navigation in western nations, like air navigation, is based on the nautical mile. Navigation also includes electronics such as GPS and Loran. Celestial navigation involves taking sights by sextant on the planets, moon, stars, sun and using the data with a nautical almanac and sight reduction tables to determine positions. Accurate time information is also needed. After nautical dusk, navigation at sea referencing the horizon is no longer possible, and after nautical dawn such navigation again becomes possible. Ice navigation involves navigating and operating a ship within sea ice conditions.Along with general navigation, seamanship involves being able to respond to weather at sea. For example, the onset of heavy or rough weather may require an alternative passage plan for the ship, as well as the use of an alternative heading to keep the vessel from rolling. Additionally, heavy weather precautions onboard such as lashing furniture in the accommodation or keeping crew off the deck is considered good seamanship when navigating in heavy weather.
Navigation and seamanship also involves a working knowledge of correct marine communications and the Global Maritime Distress and Safety System.
Seamanship also involves recognition of and navigation with Buoys including IALA maritime buoyage such as Lateral marks, Cardinal marks, Safe water marks, Special marks and Isolated danger marks.
Ship-handling and pilotage
A fundamental skill of professional seamanship is being able to manoeuvre a vessel safely with accuracy and precision both at sea and also in port and during pilotage. Unlike land based vehicles, a ship afloat is subject to the forces of the water in which it floats, as well as the resistance and effects of marine weather. A complicating factor is that the mass of a ship that has to be accounted for when stopping and starting, as the inertia of large vessels may take large distances to stop and therefore ship-handlers must be aware of basic Hydrodynamics and the charted area, including the depth of water in which their ship is navigating.Ship-handling in coastal areas may involve arriving and departing a berth, anchorage or buoy, maneuvering in confined channels and harbours and in proximity to other ships, whilst at all times navigating safely. Seamanship also involves safe navigation in restricted waterways, for example in river and canal transits eg along the Suez canal. Crew should be able to keep the vessel from collisions, moor the vessel during canal lockgate operations and also respond to local currents and river conditions while on passage. Two other types of operations, berthing alongside another ship. These must also be combined with an understanding of a specific vessel's performance, including its propulsion and stopping distance to allow safe handling. Fundamental to low-speed maneuvering of most vessel types is an understanding of the configuration and handedness of the propeller. An effect known as propeller walk will kick the stern of the vessel to port or starboard depending on the configuration and the type of propeller, when large variations on propeller rotation speed or changes of propeller rotation direction take place. (In single-screw vessels where the rotation of the propeller is reversed on an astern bell, a standard was established that the propeller would turn clockwise when viewed from astern. This would mean that the propeller would turn counterclockwise when going astern and the stern would walk to port. This aided in docking operations, where "port side to" was the preferred situation and the vessel would be brought to the dock with a small bow-in angle and backing would flatten the angle, slow or stop the vessel and walk it alongside. An exception to this is vessels which use a controllable-pitch propeller, where the pitch and not the direction of rotation was reversed to go astern. These propellers rotate counterclockwise at all times and so the "walk" is "normal".
Other variations on propulsion include what are known as bucket rudders and Kort Nozzles where instead of a conventional rudder a pair of dish-shaped rudders, one either side of the propeller can be swivelled vertically to direct the propeller thrust through 360 degrees. Thus to put the vessel into astern mode the rudder can be rotated through 180 degrees without altering the speed and direction of the engine. Since with the conventional propeller or rudder configuration the propeller is designed to operate at maximum efficiency when going ahead, it produces far less thrust when going astern. But with the Kort Nozzle, the ahead and astern thrust is the same. Other advantages of the nozzle are the ship can be steered astern which a conventional rudder cannot, and the ship can be steered fully under control to a standstill switching between ahead and astern mode to give complete control over speed.
Mooring and anchoring
Seamanship applies to general Mooring practices and anchoring and established marine procedures for anchoring. This also includes the use of drogues as applicable.Anchor work includes an understanding and awareness of types of anchors, marks on anchors and cable and shackles. It includes learning established procedures for securing anchors and cable, use of windlasses, how to prepare the anchors/clearing away anchors for letting go, letting-go the anchor, keeping an anchor watch, clearing a foul Hawse, weighing anchor and securing anchors for sea.