NS100 Fundamentals of Naval Science
Ship Characteristics
Objectives: 1. Be familiar with basic ship structure definitions. 2. Understand shipboard compartmentation, terminology, and watertight integrity. 3. Demonstrate an understanding of the different material conditions of readiness.
Ship Structure Definitions Hull - The main body of the ship. Shell Plating - The sides of the hull. Main Deck - Uppermost deck running continuously from bow to stern. Bilge - Intersection of side plating and bottom plating. Keel - Backbone of the ship.
Ship Structure Definitions (cont’d)
Frames - Fastened to the keel, running athwartships. Support the skin and divide ship into vertical rows of compartments. Decks - “Floors” aboard ship. Divide ship into horizontal rows of of compartments. Levels - Similar to decks, located above the main deck.
Ship Structure Definitions (cont’d)
Weatherdecks - The portion of the main deck and the upper levels exposed to the weather. Bulkheads - “Walls” aboard ship. Overheads - “Ceilings” aboard ship. Compartments - “Rooms” aboard ship. Bounded by overheads, bulkheads and decks.
Hull Reference Terms Ballast - Weight added to lower part of ship to help keep her in balance. Either permanent or controllable (ballast tanks). Bilge keel - Long narrow fins fitted to both sides of hull to minimize rolling. Bulwarks - Vertical extensions above the deck edge. High enough to keep sailors and equipment from going overboard.
Hull Reference Terms (cont’d) Draft - Vertical distance from waterline to keel. Indicates depth of water needed for ship to float. Freeboard - Vertical distance from waterline to main deck. Lifelines - Light wire ropes supported by stanchions. Serve the same purpose as bulwarks.
Hull Reference Terms (cont’d) Propeller guards- Steel braces protruding from the hull directly above the propellers. protect props from striking pier, dock or other ship. Stem - The point of the hull and the bow. Stern - The area on the aft end of the ship where both sides meet.
Hull Reference Terms (cont’d) Trim- The relationship between fore and aft draft. “In trim” “down by the bow” or “down by the stern.” List - The athwartships balance of the ship.
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Compartment and Deck Numbering Every compartment aboard a ship is given an identifying alphanumeric symbol which is marked on a label plate on or near the entrance. For example:
1 - 123 - 1 - L
Compartment and Deck Numbering (cont’d) Deck number : The first component of the compartment number indicates the deck. The main deck is numbered “1”, with decks below numbered 2, 3, 4, 5… Decks above the main deck are called levels and are numbered 01, 02, 03… as they go up.
1 - 123 - 1 - L
Compartment and Deck Numbering (cont’d) Frame number : The second part of the compartment number indicates forward and aft location by using the forwardmost frame of the compartment as a reference.
1 - 123 - 1 - L
Compartment and Deck Numbering (cont’d) Relation to the centerline: The third part of the compartment number. Zero (0) indicates a compartment on the centerline of the ship, with compartments to port labeled with even numbers, and odd numbers identifying compartments to starboard.
1 - 123 - 1 - L
Compartment and Deck Numbering (cont’d) Description of the compartment: Indicates the use of the compartment. E - engineering C - ship control (bridge,CIC) L - living spaces M - ammunition spaces Q - spaces not otherwise designated V - voids
1 - 213 - 1 - L
Shipboard Compartmenation and Watertight Integrity A ship’s structure is divided into many watertight compartments in order to maximize damage control readiness.
Material Conditions of Readiness X-ray - Least protective condition. Only X fittings are secured. Yoke - Moderate protection. X and Y fittings secured. Set at sea and inport after working hours. Zebra - Highest degree of readiness. All X, Y, and Z fittings are secured. Set during General Quarters.
Material Conditions of Readiness (cont’d)
Circle X-ray, Circle Yoke, Circle Zebra These fittings may be opened for short periods of time while that condition is set, but must be closed when not in use. Dog Zebra - Fittings secured during condition Zebra, also secured during “darken ship” condition.
Material Conditions of Readiness (cont’d)
William - Applies to fittings normally kept open. Used for maintenance and system isolation. Circle William - Normally kept open, secured for protection against Chemical, Biological, and Radiological (CBR) attack.
Review Questions 1. What is the difference between a deck and a level? 2. What is the number of the main deck? 3. When is material condition Yoke set throughout the ship? 4. Besides general quarters, when is material condition Zebra set throughout the ship? 5. What do Circle William fittings protect against?
Review Questions 6. What are Dog Zebra fittings designed to do? 7. What is the difference between list and trim? 8. If you were told, “Ensign, go to compartment 6-132-0-F to get a HT punch,” where would you go?
