SHIP TERMINOLOGY

• LENGTH OVERALL (LOA): DISTANCE FROM EXTREME FORE PART OF SHIP TO SIMILAR POINT AFT. GREATEST LENGTH OF SHIP.
• AFT PERPENDICULAR(AP): PERPENDICULAR AT A POINT WHERE THE AFT SIDE OF THE RUDDER POST MEETS THE SUMMER LOAD LINES OR THE CENTER OF RUDDER STOCK IF NO RUDDER POST.
• FORWARD PERPENDICULAR: PERPENDICULAR AT A POINT WHERE SUMMER LOAD LINE CUTS STEM
• LENGTH BETWEEN PERPENDICULAR: DISTANCE BETWEEN FORWARD PERPENDICULAR AND AFT PERPENDICULAR.
• LENGTH ON WATER LINE: LARGEST LENGTH ON WATER LINE.
• MIDSHIP: POINT MIDWAY BETWEEN AFT PERPENDICULAR AND FORWARD PERPENDICULAR.
• BREADTH(EXTREME): GREATEST BREADTH OF SHIP (MEASURED OUTSIDE THE SHELL PLATING).
• BREADTH(MOULDED): GREATEST LENGTH OF SHIP AS MEASURED TO INSIDE STRAKES OF SHELL PLATING
• DEPTH(EXTREME): DEPTH OF SHIP FROM UNDERSIDE OF KEEL TO TOP OF THE DECK BEAM AT THE SIDE OF UPPERMOST CONTINUOUS DECK AMIDSHIP.
• DEPTH(MOULDED): DEPTH MEASURED FROM TOP OF KEEL TO UNDERSIDE OF DECK AT SHIP SIDE.
• DRAUGHT(EXTREME): DISTANCE FROM BOTTOM OF KEEL TO WATERLINE (LOADED DRAUGHT IS MAXIMUM DRAUGHT TO WHICH A VESSEL CAN BE LOADED).
• DRAUGHT (MOULDED): DISTANCE FROM TOP OF KEEL TO WATERLINE.
• FREE BOARD:  DISTANCE FROM WATERLINE TO TOP OF DECK PLATING AT THE SIDE OF DECK AMIDSHIP.
• CAMBER/ROUND OF BEAM:TRANSVERSE CURVATURE OF DECK FROM CENTER LINE DOWN TO SIDE. HEIGHT OF DECK AT CENTER LINE ABOVE HEIGHT OF DECK SIDE. HELPS OF SHED WATER FROM DECK AND ADDS TO ITS LONG STRENGTH
• SHEER: RISE OF DECK FORWARD AND AFT (CURVATURE OF DECK FORE AND AFT RISING FROM MIDSHIP TO MAXIMUM AT ENDS). FORWARD SHEER IS TWICE THAT AT AFT. MAKE SHIP MORE SEA WORTHY BY RAISING THE DECK AT FORE AND AFT END FURTHER FROM WATER AND BY REDUCING VOLUME OF WATER COMING ON DECK)
• RISE OF FLOOR: RISE OF BOTTOM SHELL PLATING ABOVE HORIZONTAL BASE LINE MEASURED AT SHIP SIDE. FACILITATE DRAINAGE OF LIQUID TO SHIP CENTER LINE
• BILGE RADIUS : RADIUS OF ARC CONNECTING THE SIDE OF SHIP TO BOTTOM AT MIDSHIP. THE OUTSIDE OF THE MIDSHIP SECTION OF EVERY SHIP IS VERY NEARLY  A RECTANGLE WITH ITS LOWER CORNER ROUNDED. THE LOWER CORNER IS CALLED BILGES.
• TUMBLE HOME: INWARD CURVATURE OF SIDE PLATING FROM VERTICAL  AS IT EXTEND UPWARD TOWARD DECK EDGE.
• FLARE : OUTWARD CURVATURE OF SIDE SHELL PLATING ABOVE THE WATER LINE AT FORWARD END OF SHIP.
• CUT UP : CURVATURE AT FWD AND AFT PART OF SHIP.
• BUTTOCK LINE: REGULARLY SPACED REFERENCE PLANE CUTTING THE SHIP HULL PARALLEL TO THE CENTER LINE. GENERALLY SPACED ONE, TWO, FOUR FEET APART.
• MARGIN LINE: AN IMAGINARY LINE 16 MM BELOW THE BULKHEAD DECK AT SIDE . IT IS ASSUMED IF ANY SINKAGE, HEEL OR TRIM CAUSES THE MARGIN LINE TO BE IMMERSED, THE VESSEL HAS FOUNDERED.
• DISPLACEMENT: MASS OF SHIP AND EVERYTHING IT CONTAINS. A SHIP HAS DIFFERENT VALUE OF DISPLACEMENT AT DIFFERENT DRAUGHTS.
• LIGHT WEIGHT: MASS OF EMPTY SHIP WITHOUT STORES ,FUEL, WATER, CREW OR THEIR EFFECTS.
• DEADWEIGHT: MASS OF CARGO , STORES, BALLAST, FRESH WATER, FUEL OIL, CREW, PASSENGER, AND THEIR EFFECT ON BOARD.                                                               (DEADWEIGHT= DISPLACEMENT- LIGHTSHIP WEIGHT)
• TONNAGE: MEASURE OF ENCLOSE VOLUME OF VESSEL. ONE REGISTERED TON IS 100 CUBIC FEET VOLUME
• GROSS TONNAGE: MEASURE OF VOLUME INSIDE A VESSEL WHICH INCLUDE ALL AREA FROM KELL TO FUNNEL AND BOW TO STERN. GRT IS THE VOLUME OF SPACE ABOVE THE DECK OF A MERCHANT SHIP WHICH IS AVAILABLE FOR CARGO, STORES, FUEL, PASSANGER,AND CREW                                                                      1 GRT = 100 CUBIC FEET OF CAPACITY.
• NET TONNAGE: GROSS TONNAGE- TONNAGE OF SPACES WHICH ARE REQUIRED FOR THE SAFE WORKING OF SHIP THAT IS ACCOMODATION , NAVIGATION, MACHINERY SPACES , FUEL ETC.