CHAPTER 3 SHIP COMPARTMENTATION AND …

1 CHAPTER 3 ship COMPARTMENTATION AND WATERTIGHTINTEGRITYL earning Objectives:Recall the definitions of termsused to define the structure of the hull of a ship and thenumbering systems used for compartment numberdesignations. identify the different types of watertightclosures and recall the inspection procedures for theclosures. Recall the requirements for the three materialconditions of readiness, the purpose and use of theCompartment Checkoff List (CCOL) and damagecontrol closure log, and the procedures for checkingwatertight ship s ability to resist sinking after sustainingdamage depends largely on the ship scompartmentation and watertight integrity.

2 Whenthese features are maintained properly, fires andflooding can be isolated within a limited area. Withoutcompartmentation or watertight integrity, a ship facesalmost certain doom if it is severely damaged and theemergency damage control (DC) teams are notproperly trained or this CHAPTER , you will be introduced tocompartmentation, material conditions of readiness,watertight integrity, and how they relate to each will also learn about compartment checkoff lists,the DC closure log, the proper care of access closuresand fittings, compartment inspections, the ship s draft,and the sounding and security patrol watch.

3 Theinformation in this CHAPTER will assist you incompleting your personnel qualification standards(PQS) for basic damage Objective:Recall the definitions of termsused to define the structure of the hull of a ship and thenumbering systems used to identify the differentcompartments of a COMPARTMENTATION of a ship is a major featureof its watertight integrity. COMPARTMENTATION dividesthe interior area of a ship s hull into smaller spaces bythe use of structural to figure 3-1 while reviewing the informationon structural 3-1. Illustrative hull keel is the backbone of the ship . The keel doesnot extend below the ship s bottom.

4 Its usual shape isthat of an I-beam. All other members used inconstructing the hull are attached, either directly orindirectly, to the athwartship structure consists of transverseframes and floors. The floors run outboard from thekeel to the turn of the bilge (where the bottom turnsupward). This is where they are attached to thetransverse frames that extend upward to the main , running parallel with the keel, are knownas longitudinal frames. From the turn of the bilge upthe sides, they are called stringers. The network offloors and longitudinal members resembles ahoneycomb and is known as cellular construction,which greatly strengthens the bottom.

5 When platingcovers the honeycomb structure, double bottoms areformed. The space between the inner and outerbottoms (known as tanks) is used for liquid forward end of the keel is extended upward in thestem. The after end has a similar extension, called thesternpost. The part of the stem above water is the prow;the forward edge of the stem is the interior of a ship is divided into compartmentsby vertical walls, called bulkheads, which run bothtransversely and longitudinally. Most bulkheads aremerely partitions, but transverse watertight bulkheadsare spaced at appropriate intervals. These structuralbulkheads extend from the keel to the main deck andfrom side to side.

6 They provide extra transversestiffening and partition the hull into independentwatertight sections. Large ships have a series oflongitudinal side bulkheads and tanks that provideprotection against torpedoes. The outer tanks usuallyare filled with oil or water. The inner tanks, which arecalled voids, are empty. The innermost bulkhead iscalled a holding bulkhead. When a torpedo hits, theouter tanks, although ruptured, absorb enough energyfrom the explosion that the holding bulkhead willremain intact. This helps to prevent flooding of thevital hull plating is fastened to the framework inlongitudinal rows, called strakes.

7 The keel forms thecenter strake. The strakes are lettered, beginning withthe A-strake on either side of the keel and extending upto the main deck. Some of the strakes also have A-strake is called the garboard strake; the strakealong the turn of the bilge is the bilge strake; theuppermost strake is the sheer stated, the projecting keel, running along thebottom near the turn of the bilge, is called the bilgekeel. The purpose of the bilge keel is to reduce rollingof the shiprollsfrom side to side. A shippitcheswhen it goes up and down fore and shipyawswhen the bow swings to port andstarboard because of wave upper edges of the sides where the sheerstrakes join the main deck are called the gunwales(rhymes with funnels).

8 The foremost part of the ship ,where the gunwales join the stem, is known as the eyesof the ship (fig. 3-2). Where the gunwales curve inwardto the sternpost are the port and starboard water level along the hull of a ship afloat is thewaterline. The vertical distance from the keel to thewaterline is the ship s draft. Freeboard is the distancefrom the waterline to the main floors of a ship are called decks (fig. 3-3).Decks divide the ship into layers and provideadditional hull strength and protection for internalspaces. The lower surface of each deck forms theoverhead (never the ceiling) of the compartmentbelow.

9 Compartments are the spaces within a DECKBULWARKFORECASTLEEYESOVERHANGRUDDERF REEBOARDWATERLINEDRAFTHAWSEPIPESTEMBOWPR OPELLERSTRUTPROPELLERSHAFTDCf0302 Figure 3-2. Hull DECKSUPPER DECKFORECASTLE DECKMAIN DECKMAIN DECKPOOP DECKFORWARD WELL DECKAFTER WELL DECKDCf0303 Figure 3-3. Weather steel deck is made of strakes running fore andaft. The outboard strake in the deck plating iscomposed of stringer plates, which are welded orriveted to the side plates and are, therefore, importantstrength members. Decks are supported by transverseframes (deck beams) and by longitudinal (deck)girders. Vertical steel pillars that are called stanchionsprovide other means of deck support.

10 These aremounted one above the other or one above a strengthbulkhead. (The short posts used as lifeline supportsalso are called stanchions.) Decks usually are archedfrom the gunwale to the centerline to provide fordrainage of water and to strengthen the deck or part of a deck exposed to the weather iscalled a weather deck (fig. 3-3). Bulwarks are solidfencing along the gunwale of the main (weather) are fitted with freeing ports (scuppers) toallow the water to run off during heavy deck that extends from side to side and stem tostern is a complete deck. In aircraft carriers theuppermost complete deck is the flight deck, from whichaircraft take off and land.