7 1. General – Units of measurement In engineering 3 types of METRIC UNITS are used:1. BASIC METRIC UNITS refer to LINEAR DIMENSIONS, i.e. those which can be measured in a straight line and are:a) LENGTHb) HEIGHTc) WIDTH or BREADTHd) THICKNESSe) DEPTHOther basic units as KILOGRAMME, SECOND, RADIAN are used to describe physical quantities as MASS, TIME, ANGLE
8 1. General – Units of measurement 2. DERIVED METRIC UNITSDERIVED METRIC UNITS are the products of the BASIC units and are:AREAVOLUMECAPACITYAREA is obtained by multiplying the basic units of LENGHT and BREADTH (WIDTH) and is measured in SQUARE METRES
9 1. General – Units of measurement VOLUME and CAPACITY are measured in CUBED LINEAR UNITS as CUBIC METRESThe volume & capacity of liquids can be measured in LITRES.VOLUME is the “ space occupied by an object or substance “CAPACITY is the “ ability of a container or tank to hold something”.
10 1. General – Units of measurement 3. COMPOUND METRIC UNITSCOMPOUND UNITS are made up of BASIC and DERIVED UNITS OF MEASUREMENT such as :STRESSPOWERENERGYACCELERATIONWORK
11 1.1 Basic metric units- exercises The bar is three metres ( GB ) / meters ( US ) long.The bar is three meters in lenght.The bar has a lenght of three meters.The lenght of the bar is three meters.The driving belt is sixty millimeters broad / wide.The driving belt is sixty millimeters in breadth / width.The driving belt has a breadth / width of sixty millimeters.The breadth / width of the driving belt is sixty millimeters.The support tower is one / a hundred meters high.The support tower is one hundred meters in height.The support tower has a height of one hundred meters.The height of the support tower is one hundred meters.
12 1.1 Basic metric units- exercises The sheet is three millimeters thick.The sheet has a thickness of three millimeters.The thickness of the sheet is three millimeters.The trench is two meters deep.The trench is two meters in depth.The trench has a depth of two meters.The depth of the trench is two meters.The block has a mass of 50 kilogrammes ( GB ) / kilograms ( US ).The block is of 50 kg. mass.The mass of the block is fifty kilogrammes.
13 1.2 Derived metric units - exercises The plate has an area of six square meters.The plate is six square meters in area.The area of the plate is six square meters.The brick has a volume of one thousand six hundred cubic centimeters.The brick is one thousand six hundred cubic centimeters in volume.The volume of the brick is one thousand six hundred cubic centimeters.The tank has a capacity of twenty - four cubic meters.The tank is twenty - four cubic meters in capacity.The capacity of the tank is twenty - four cubic meters.
21 4.1 Bale spacethe volume of the cargo holds that can be used to carry general cargo
22 4.2 Grain spacethe volume of the cargo holds that can be used to carry dry bulk cargo
23 4.3 Oil space98 % of the total volume of wet bulk tanks
24 4.4 Ullageempty space on top of the liquid level that will prevent a tank from overflowing when oil expands due to heat
25 5. Displacementthe amount of water that the ship displaces while floatingthe weight of the displaced fluid is directly proportional to the volume of the displaced fluid (if the surrounding fluid is of uniform density).
26 5. DisplacementArchimedes’ principls (Archimede’s principle) states that the buoyant force on an object is going to be equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational constant, e.g. among completely submerged objects with equal masses, objects with greater volume have greater buoyancy.
27 6. Dimensions Length Over All (L.O.A.) Length between Perpendiculars Breadth / WidthMoulded breadthMoulded depthBeam
30 6.1 Length Over All (L.O.A.) the length from the extreme point of stern to the extreme point of stem (bow)
31 6.2 Breadth / Widththe breadth (width) measured to the outside surface of plating
32 6.3 Moulded breadththe horizontal distance between the insides of the mouldsbreadth at the widest point measured to the outside surface of the frames
33 6.4 Moulded depthvertical distance between the insides of the moulds (including the double bottom)the vertical distance amidships from the top of keel to the top of deck beam at the underside of the deck plating at ship's side
34 6.5 Beam the extreme breadth of the vessel important for obtaining clearance to proceed in restricted, narrow fairways
35 6.6 Length Between Perpendiculars is measured between the fore perpendicular and aft-perpendicular
36 6.7 Construction waterline line to which the ship may be loaded in summer
37 6.8 Draught (draft)the vertical distance from the surface of the water (waterline) to the vessel's bottomloaded draft, light draft, salt-water draft, fresh- water draft
38 6.9 Freeboardthe vertical distance from the water to the weather deck edge at any point in the lenght of the ship distance between the deckline and waterline
39 6.10 Height or Air draughtdistance from the waterline to the highest point of the vesselvertical clearance
40 6.11 Underkeel Clearancethe distance between keel and seabed