Ship Handling 101 – Basic Seamanship Terms
Basic seamanship is something that is often taken for granted. Anyone who has sailed a vessel on the waters of the United States, whether inland or coastal, has probably made the basic error of assuming the other vessels they encounter will be driven by competent mariners. For the most part, this assumption would be correct. But there are many Sailors on the water who understand very little of what goes into maneuvering their vessel, let alone the factors involved in maneuvering the exceptionally large vessels often encountered on approaches to shipping ports. With some of these vessels weighing over 100,000 gross tons, their crew can do very little to avoid destroying the small pleasure craft who erroneously crosses their path.
My past experience running the deck of an aircraft carrier provides a unique perspective on the capabilities of other mariners. It also has given me an inside look at how the personnel responsible for safely navigating these monster ships think – and it’s not always in line with good seamanship. Running the deck of any ship means you are responsible for where the ship is going and how it gets there. No maneuver is executed without the implicit consent of whoever holds the deck no matter who might be conning, or driving, the ship.
Although the law of gross tonnage should always apply since the 30 foot fishing boat will lose in a collision with a ship over 1,000 feet long coming in at approximately 95,000 tons, that will be small consolation for the boaters turned swimmers and those in charge of safely maneuvering the carrier. Careers will end, ship’s will be damaged or destroyed, and people may be injured or lives lost if those responsible for safe navigation do not understand the basic Rules of the Road, characteristics of their vessel, and the basic terms one might hear from other Sailors.
Although I began posting these Ship Handling 101 hubs with a basic primer on propeller forces, writing that article made me realize I should have started with basic seamanship terms. There are way too many terms to be listed in a basic glossary, so I’ll try to hit the highpoints so anyone following this series will understand what is being discussed.
-Abaft. Any part of a ship aft of amidships.
-Accommodation Ladder. An upper and lower platform connected by a ladder. Used as a means for boarding a ship while underway or moored if a brow is not available.
-Advance. The distance travelled ahead from the time a rudder is turned, or put over, to the time a ship is on a new course.
-Aft. The after end of a boat. Also called the stern.
-Amidships. Center of a vessel. A point approximately halfway between the bow and stern and the ship’s sides.
-Athwartships. Something that crosses from side to side on a ship. For example, an athwartships passageway is a corridor that runs from side to side.
-Brow. A gangplank, brows are ramps used to traverse ship to ship or ship to pier.
-Centerline. A line dividing a ship in half from bow to stern.
-Current. The horizontal motion of water over the Earth’s surface.
-Deck fittings. Those items used to secure mooring and working lines aboard ship including bits, cleats, and pad eyes.
-Drift. Velocity, in knots, of current.
-Ebb Current. The movement of water away from land corresponding with a falling tide.
-Flood Current. The movement of water toward land corresponding with a rising tide.
-Fore. The forward end of the ship or the bow.
-Ground tackle. The equipment used in anchoring or mooring utilizing a ship’s anchors including anchors, anchor cables/chains, anchor windlasses, chain stoppers, and all associated equipment.
-Inboard. Usually describes an inside area of a ship or an object near the ship’s centerline.
-Marlinspike Seamanship. Care and use of line including tying knots, making splices, and fashioning useful and decorative articles from small stuff and twine.
-Outboard. An object away from the centerline of the ship or an area outside the side of the ship.
-Port. When facing the bow, the side of the ship to your left.
-Seamanship. The art of handling ships.
-Set. The direction a ship is moved as a result of the influence of current.
-Slack Water. A brief period of time between Flood Current and Ebb Current when no horizontal movement of water can be detected.
-Small Stuff. Line less than 1.75 inches in diameter is referred to as small stuff.
-Squatting. As a ship’s speed increases, the hull will sink. At a specific speed, peculiar to the type of ship, the bow will rise and the stern will sink creating squatting. This effect is amplified in shallow water providing impressive wakes. Often harbor and channel speeds will be designated to prevent squatting and the generation of destructive wakes.
-Starboard. When facing the bow, the side of the boat to your right.
-Transfer. The distance travelled laterally from the time a rudder is put over to the time a ship is on a new course.
While not all inclusive, the terms above will help the reader understand the ship handling hubs. With enough practice, you would even understand what was meant if a Sailor directed you to head forward to the athwartships passageway then inboard until you reach centerline where you’ll go aft until you reach your destination. It’s always fun to play with these terms whenever a new Sailor arrives aboard a ship! In all seriousness, ship handling and proper seamanship separates good ships from bad and will often be known up and down the waterfront. ADM Chester Nimitz once admonished Sailors that “to ensure safety at sea, the best that science can devise and that naval organization can provide must be regarded only as an aid, and never as a substitute for good seamanship, self-reliance, and sense of ultimate responsibility which are the first requisites in a seaman.”
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