Lesson two Definitions, Principal Dimensions Before studying in detail the various technical branches of naval architecture it is important to define chapters The purpose of this chapter is to explain these terms and to familiarise the reader with them. In the first place the dimensions by which the size of a ship is measured will be considered; they are referred to as ' principal dimensions. The ship, like any solid body, requires three dimensions to define its size, and these are a length, a breadth and a depth. Each of these will be considered in turn Principal dimensions c There are various ways of defining the length of a ship, but first the length between perpendiculars will be nsidered. The length between perpendiculars is the distance measured parallel to the base at the level of the summer load waterline from the after perpendicular to the forward perpendicular. The after perpendicular is taken as the after side of the rudder post where there is such a post, and the forward perpendicular is the vertical line drawn through the intersection of the stem with summer load waterline. In ships where there is no rudder post the after perpendicular is taken as the line passing through the centre line of the rudder pintals. The perpendiculars and the length between perpendiculars are shown in Figure I The length between perpendiculars(LBp)is used for calculation purposes as will be seen later, but it will be obvious from Figure I that this does not represent the greatest length of the ship. For many purposes, such as the docking of a ship, it is necessary to know what the greatest length of the ship is. This length is known as the length of the extreme point at the after end to a similar point at the forward end. This can be clearly seen by referring again to Figure 1. In most ships the length overall will exceed by a considerable amount the length between perpendiculars. The excess will include the overhang of the stern and also that of the stem where the stem is raked forward. In modern ships having large bulbous bows the length overall Loa may have to be measured to the extreme point of the bulb a third length which is often used, particularly when dealing with ship resistance, is the length on the waterl LwL.This is the distance measured on the waterline at which the ship is floating from the intersection of the stern with the waterline to the length is not a fixed quantity for a particular ship, as it will depend upon the waterline at which the ship is floating and upon the trim of the ship. This length is also shown in Figure
Lesson Two Definitions, Principal Dimensions Before studying in detail the various technical branches of naval architecture it is important to define chapters. The purpose of this chapter is to explain these terms and to familiarise the reader with them. In the first place the dimensions by which the size of a ship is measured will be considered; they are referred to as ‘principal dimensions’. The ship, like any solid body, requires three dimensions to define its size, and these are a length, a breadth and a depth. Each of these will be considered in turn. Principal dimensions Length There are various ways of defining the length of a ship, but first the length between perpendiculars will be considered. The length between perpendiculars is the distance measured parallel to the base at the level of the summer load waterline from the after perpendicular to the forward perpendicular. The after perpendicular is taken as the after side of the rudder post where there is such a post, and the forward perpendicular is the vertical line drawn through the intersection of the stem with summer load waterline. In ships where there is no rudder post the after perpendicular is taken as the line passing through the centre line of the rudder pintals. The perpendiculars and the length between perpendiculars are shown in Figure 1. The length between perpendiculars (LBP) is used for calculation purposes as will be seen later, but it will be obvious from Figure 1 that this does not represent the greatest length of the ship. For many purposes, such as the docking of a ship, it is necessary to know what the greatest length of the ship is. This length is known as the length of the extreme point at the after end to a similar point at the forward end. This can be clearly seen by referring again to Figure 1. In most ships the length overall will exceed by a considerable amount the length between perpendiculars. The excess will include the overhang of the stern and also that of the stem where the stem is raked forward. In modern ships having large bulbous bows the length overall LOA may have to be measured to the extreme point of the bulb. A third length which is often used, particularly when dealing with ship resistance, is the length on the waterline LWL. This is the distance measured on the waterline at which the ship is floating from the intersection of the stern with the waterline to the length is not a fixed quantity for a particular ship, as it will depend upon the waterline at which the ship is floating and upon the trim of the ship. This length is also shown in Figure 1
fter shee Upper deck o orward side Summer load waterline of stem After side of rudder post or centre line of rudder pintles bulbous bow length between perpendiculars(L Length on waterline Fig 1 The mid point of the length between perpendiculars is calledamidships'and the ship is usually broadest at this point. The breadth is measured at this position and the breadth most commonly used is called the breadth moulded. It may be defined simply as the distance from the inside of plating on one side to a simi lar point on the other side measured at the broadest part of the ship As is the case in the length between perpendiculars, the breadth moulded dose not represent the greatest breadth the breadth extreme is required(see Figure 2 ) In many ships the breadth extreme is the breadth moulded plus the thickness of the shell plating where the strakes of shell plating were overlapped the breadth extreme was equal to the breadth moulded plus four thicknesses of shell plating, but in the case of modern welded ships the extra breadth consists of two thicknesses of shell plating only The breadth extreme may be much greater than this in some ships, since it is the distance from the extre overhang on one side of the ship to a similar point on the other side. This distance would include the overhang of decks, a feature which is sometimes found in passenger ships in order to provide additional deck area. It would be measured over fenders, which are sometimes fitted to ships such as cross channel vessels which have to operate and out of port under their own power and have fenders provided to protect the sides of the ships when coming ⊥ Breadth extreme Inside of pla ting p
Breadth The mid point of the length between perpendiculars is called ‘amidships’and the ship is usually broadest at this point. The breadth is measured at this position and the breadth most commonly used is called the ‘breadth moulded’. It may be defined simply as the distance from the inside of plating on one side to a similar point on the other side measured at the broadest part of the ship. As is the case in the length between perpendiculars, the breadth moulded dose not represent the greatest breadth the breadth extreme is required (see Figure 2 ). In many ships the breadth extreme is the breadth moulded plus the thickness of the shell plating where the strakes of shell plating were overlapped the breadth extreme was equal to the breadth moulded plus four thicknesses of shell plating, but in the case of modern welded ships the extra breadth consists of two thicknesses of shell plating only. The breadth extreme may be much greater than this in some ships, since it is the distance from the extreme overhang on one side of the ship to a similar point on the other side. This distance would include the overhang of decks, a feature which is sometimes found in passenger ships in order to provide additional deck area. It would be measured over fenders, which are sometimes fitted to ships such as cross channel vessels which have to operate in and out of port under their own power and have fenders provided to protect the sides of the ships when coming alongside quays
Depth The third principal dimension is depth, which varies along the length of the ship but is usually measured ant amidships. This depth is known as the ' depth moulded and is measured from the underside of the plating of the deck at side amidships to the base line. It is shown in Figure 2(a). It is sometimes quoted as a depth moulded to upper deck'or 'depth moulded to second deck,, etc. Where no deck is specified it can be taken the depth is measured to the uppermost continuous deck. In some modern ships there is a rounded gunwale as shown in Figure 2(b). In such cases the depth moulded is measured from the intersection of the deck line continued with the breadth moulded line The three principal dimensions give a general idea of the size of a ship but there are several other features which have to be considered and which could be different in two ships having the same length, breadth and depth The more important of these will now be defined Sheer is the height of the deck at side above a line drawn parallel to the base and tangent to the length of the ship and is usually greatest at the ends. In modern ships the deck line at side often has a variety of shapes: it may be flat with zero sheer over some distance on either side of amidships and then rise as a straight line towards the ends; on the other hand there may be no sheer at all on the deck, which will then be parallel to the base over the entire length. In older ships the deck at side line was parabolic in profile and the sheer was quoted as its value the forward and after perpendiculars as shown in Figure 1. So called'standard sheer was given by the formulae Sheer forward (in)=0.2Lf+20 (in)=0.Ln+10 These two formulae in terms of metric units would give Sheer forward (cm)=1.666Lm+50.8 (cm)=0.833Lm+254 It will be seen that the sheer forward is twice as much as the sheer aft in these standard formulae. It was often the case. however that considerable variation was made from these standard values. sometimes the sheer forward was increased while the sheer after was reduced. Occasionally the lowest point of the upper deck was some distance aft of amidships and sometimes departures were made from the parabolic sheer profile. The value of sheer and particularly the sheer forward was to increase the height of the deck above water (the height of platform'as it was called )and this helped to prevent water being shipped when the vessel was moving through rough sea. The reason for the abolition of sheer in some modern ships is that their depths are so great that additional height of the deck above water at the fore end is unnecessary from a seakeeping point of view Deletion of sheer also tends to make the ship easier to construct, but on the other hand it could be said that the appearance of the ship suffers in consequence Camber or round of beam is beam is defined as the rise of the deck of the ship in going from the side to the centre as shown in Figure 3(a). The camber curve used to be parabolic but here again often nowadays straight line camber curves are used or there may be no camber at all on decks. Camber is useful on the weather deck of a ship from a drainage point of view, but this may not be very important since the ship is very rarely upright and at rest. Often, if the weather deck of a ship is cambered, the lower decks particularly in passenger ships may have no camber at all. as this makes for horizontal decks in accommodation which is an advantage Camber is usually stated as its value on the moulded breadth of the ship and standard camber was taken one-fiftieth of the breadth. The camber on the deck diminishes towards the ends of the ship as the deck breadths ecome smaller Bilge radius An outline of the midship section of a ship is shown in Figure 3(a). In many full'cargo ships the section is virtually a rectangle with the lower corners rounded off. This part of the section is referred to as the bilge and the shape is often circular at this position. The radius of the circular arc foming the bilge is called the 'bilge radius
Depth The third principal dimension is depth, which varies along the length of the ship but is usually measured ant amidships. This depth is known as the ‘depth moulded and is measured from the underside of the plating of the deck at side amidships to the base line. It is shown in Figure 2(a). It is sometimes quoted as a ‘depth moulded to upper deck’ or ‘depth moulded to second deck’, etc. Where no deck is specified it can be taken the depth is measured to the uppermost continuous deck. In some modern ships there is a rounded gunwale as shown in Figure 2(b). In such cases the depth moulded is measured from the intersection of the deck line continued with the breadth moulded line. Other features The three principal dimensions give a general idea of the size of a ship but there are several other features which have to be considered and which could be different in two ships having the same length, breadth and depth. The more important of these will now be defined. Sheer Sheer is the height of the deck at side above a line drawn parallel to the base and tangent to the length of the ship and is usually greatest at the ends. In modern ships the deck line at side often has a variety of shapes: it may be flat with zero sheer over some distance on either side of amidships and then rise as a straight line towards the ends; on the other hand there may be no sheer at all on the deck, which will then be parallel to the base over the entire length. In older ships the deck at side line was parabolic in profile and the sheer was quoted as its value on the forward and after perpendiculars as shown in Figure 1. So called ‘standard’ sheer was given by the formulae: Sheer forward (in) =0.2Lft+20 Sheer aft (in) =0.1Lft+10 These two formulae in terms of metric units would give: Sheer forward (cm) =1.666Lm+50.8 Sheer aft (cm) =0.833Lm+25.4 It will be seen that the sheer forward is twice as much as the sheer aft in these standard formulae. It was often the case, however, that considerable variation was made from these standard values. Sometimes the sheer forward was increased while the sheer after was reduced. Occasionally the lowest point of the upper deck was some distance aft of amidships and sometimes departures were made from the parabolic sheer profile. The value of sheer and particularly the sheer forward was to increase the height of the deck above water (the ‘height of platform’ as it was called ) and this helped to prevent water being shipped when the vessel was moving through rough sea. The reason for the abolition of sheer in some modern ships is that their depths are so great that additional height of the deck above water at the fore end is unnecessary from a seakeeping point of view. Deletion of sheer also tends to make the ship easier to construct, but on the other hand it could be said that the appearance of the ship suffers in consequence. Camber Camber or round of beam is beam is defined as the rise of the deck of the ship in going from the side to the centre as shown in Figure 3(a). The camber curve used to be parabolic but here again often nowadays straight line camber curves are used or there may be no camber at all on decks. Camber is useful on the weather deck of a ship from a drainage point of view, but this may not be very important since the ship is very rarely upright and at rest. Often, if the weather deck of a ship is cambered, the lower decks particularly in passenger ships may have no camber at all, as this makes for horizontal decks in accommodation which is an advantage. Camber is usually stated as its value on the moulded breadth of the ship and standard camber was taken as one-fiftieth of the breadth. The camber on the deck diminishes towards the ends of the ship as the deck breadths become smaller. Bilge radius An outline of the midship section of a ship is shown in Figure 3(a). In many ‘full’ cargo ships the section is virtually a rectangle with the lower corners rounded off. This part of the section is referred to as the ‘bilge’ and the shape is often circular at this position. The radius of the circular arc forming the bilge is called the ‘bilge radius’
Some designers prefer to make the section some curve other than a circle in way of the bilge. The curve would have a radius of curvature which increases as it approaches the straight parts of the section with which it has to link up Rise offle 00r The bottom of a ship at amidships is usually flat but is not necessarily horizontal. If the line of the flat bottom is continued outwards it will intersect the breadth moulded line as shown in Figure 3(a). The height of this intersection above base is called the rise of floor. The rise of floor is very much dependent on the ship form. In ships of full form such as cargo ships the rise of floor may only be a few centimeters or may be eliminated altogether. In fine form ships much bigger rise of floor would be adopted in association with a larger bilge radius o' 5 side Bugle radius Rise of Flat of keel Fig. 3 Flat of keel A feature which was common in the days of riveted ships what was known as 'flat of keel or flat of botton Where there is no rise of floor, of course, the bottom is flat from the centre line to the point where the curve of the bilge starts. If there was a rise of floor it was customary for the line of the bottom to intersect the base line some distance from the centre line so that on either side of the centre line there was a small portion of the bottom which was horizontal, as shown in Figure 3(a). this was known as the flat of bottom'and its value lay in the fact that a rightangle connection could be made between the flat plate keel and the vertical centre girder and this connection could be accomplished without having to bevel the connecting angle bars Tumble home Another feature of the midship section of a ship which was at one time quite common but has now al most completely disappeared is what was called tumble home. This is the amount which the side of the ship falls from the breadth moulded line, as shown in Figure 3(b). Tumble home was a usual feature in sailing ships and often appeared in steel merchant ships before World War Il. Ships of the present day rarely employ this feature since its elimination makes for ease of production and it is of doubtful value Rake of stem In ships which have straight stems formed by a stem bar or a plate the inclination of the stem to the vertical is
Some designers prefer to make the section some curve other than a circle in way of the bilge. The curve would have a radius of curvature which increases as it approaches the straight parts of the section with which it has to link up. Rise of floor The bottom of a ship at amidships is usually flat but is not necessarily horizontal. If the line of the flat bottom is continued outwards it will intersect the breadth moulded line as shown in Figure 3(a). The height of this intersection above base is called the ‘rise of floor ’. The rise of floor is very much dependent on the ship form. In ships of full form such as cargo ships the rise of floor may only be a few centimeters or may be eliminated altogether. In fine form ships much bigger rise of floor would be adopted in association with a larger bilge radius. Flat of keel A feature which was common in the days of riveted ships what was known as ‘flat of keel ’ or ‘flat of bottom ’. Where there is no rise of floor, of course, the bottom is flat from the centre line to the point where the curve of the bilge starts. If there was a rise of floor it was customary for the line of the bottom to intersect the base line some distance from the centre line so that on either side of the centre line there was a small portion of the bottom which was horizontal, as shown in Figure 3(a). this was known as the ‘flat of bottom’ and its value lay in the fact that a rightangle connection could be made between the flat plate keel and the vertical centre girder and this connection could be accomplished without having to bevel the connecting angle bars. Tumble home Another feature of the midship section of a ship which was at one time quite common but has now almost completely disappeared is what was called ‘tumble home’. This is the amount which the side of the ship falls in from the breadth moulded line, as shown in Figure 3(b). Tumble home was a usual feature in sailing ships and often appeared in steel merchant ships before World War II. Ships of the present day rarely employ this feature since its elimination makes for ease of production and it is of doubtful value. Rake of stem In ships which have straight stems formed by a stem bar or a plate the inclination of the stem to the vertical is
called the rake. It may be defined either by the angle to the vertical or the distance between the intersection of the stem produced with the base line and the forward perpendicular. When ships have curved stems in profile, especially where they also have bulbous bows, stem rake cannot be simply defined and it would be necessary define the stem profile by a number of ordinates at different waterlines In the case of a simple straight stem the stem line is usually joined up with the base line by a circular are, but sometimes a curve of some other form is used, in which case several ordinates are required to define its shape Draught and The draught at which a ship floats is simply the distance from the bottom of the ship to the waterline. If the waterline is parallel to the keel the ship is said to be floating on an even keel, but if the waterline is not parallel then the ship is said to be trimmed If the draught at the after end is greater than that at the fore end the ship is trimmed by the stern and if the converse is the case it is trimmed by the bow or by the head. The draught can be measured in two ways, either as a moulded draught which is the distance from the base line to the waterline, or as an extreme draught which is the distance from the bottom of the ship to the waterline. In the modern welded merchant ship to the waterline. In the modern welded merchant ship these two draughts differ only by one thickness of plating but in certain types of ships where, say, a bar keel is fitted the extreme draught would be measured to the underside of the keel and may exceed the moulded draught of by 15-23cm(6-9in). It is important to know the draught of a ship, or how much water the ship is'drawing, and so that the draught may be readily obtained draught marks are cut in the stem and the stern. These are 6 in high with a space of 6in between the top of one figure and the bottom of the next one. When the water level is up to the bottom of a particular figure the draught in feet has the value of that figure. If metric units are used then the figures would probably be 10 cm high with a 10 cm spacing In many large vessels the structure bends in the longitudinal vertical plane even in still water, with the result that the base line or the keel does not remain a straight line. The mean draught at which the vessel is floating is not then simply obtained by taking half the sum of the forward and after draughts. To ascertain how much the vessel is hogging or sagging a set of draught marks is placed amidships so that if da, de and df are the draughts at the after end amidships and the forward end respectively then da +do Hog or sag= 2 When use is made of amidship draughts it is necessary to measure the draught on both sides of the ship and take the mean of the two readings in case the ship should be heeled one side or the other The difference between the forward and after draughts of s ship is called the trim, so that trim T=da- df, and as previously stated the ship will the said to be trimming by the stern or the bow according as the draught aft or the draught forward is in excess. For a given total load on the ship the draught will have its least value when the ship is on an even keel. This is an important point when a ship is navigating in restricted depth of water or when entering a dry dock. Usually a ship should be designed to float on an even keel in the fully loaded condition, and if this is not attainable a small trim by the stern is aimed at. Trim by the bow is not considered desirable and should be avoided as it reduces the height of platform forward and increases the liability to take water on board in rou Freeboard may be defined as the distance which the ship projects above the surface of the water or the distane measured downwards from the deck to the waterline. The freeboard to the weather deck, for example, will vary along the length of the ship because of the sheer of the deck and will also be affected by the trim, if any. Usually the freeboard will be a minimum at amidships and will increase towards the ends Freeboard has an important influence on the seaworthiness of a ship. The greater the freeboard the greater is the above water volume, and this volume provides reserve buoyancy, assisting the ship to rise when it goes through waves. The above water volume can also help the ship to remain afloat in the event of damage. It will be seen later that freeboard has an important influence on the range of stability. Minimum freeboards are laid down
called the ‘rake’. It may be defined either by the angle to the vertical or the distance between the intersection of the stem produced with the base line and the forward perpendicular. When ships have curved stems in profile, and especially where they also have bulbous bows, stem rake cannot be simply defined and it would be necessary to define the stem profile by a number of ordinates at different waterlines. In the case of a simple straight stem the stem line is usually joined up with the base line by a circular are, but sometimes a curve of some other form is used, in which case several ordinates are required to define its shape. Draught and trim The draught at which a ship floats is simply the distance from the bottom of the ship to the waterline. If the waterline is parallel to the keel the ship is said to be floating on an even keel, but if the waterline is not parallel then the ship is said to be trimmed. If the draught at the after end is greater than that at the fore end the ship is trimmed by the stern and if the converse is the case it is trimmed by the bow or by the head. The draught can be measured in two ways, either as a moulded draught which is the distance from the base line to the waterline, or as an extreme draught which is the distance from the bottom of the ship to the waterline. In the modern welded merchant ship to the waterline. In the modern welded merchant ship these two draughts differ only by one thickness of plating, but in certain types of ships where, say, a bar keel is fitted the extreme draught would be measured to the underside of the keel and may exceed the moulded draught of by 15-23cm (6-9in). It is important to know the draught of a ship, or how much water the ship is ‘drawing’, and so that the draught may be readily obtained draught marks are cut in the stem and the stern. These are 6 in high with a space of 6in between the top of one figure and the bottom of the next one. When the water level is up to the bottom of a particular figure the draught in feet has the value of that figure. If metric units are used then the figures would probably be 10 cm high with a 10 cm spacing. In many large vessels the structure bends in the longitudinal vertical plane even in still water, with the result that the base line or the keel does not remain a straight line. The mean draught at which the vessel is floating is not then simply obtained by taking half the sum of the forward and after draughts. To ascertain how much the vessel is hogging or sagging a set of draught marks is placed amidships so that if da, d and df are the draughts at the after end amidships and the forward end respectively then Hog or sag= 2 da + df - d When use is made of amidship draughts it is necessary to measure the draught on both sides of the ship and take the mean of the two readings in case the ship should be heeled one side or the other. The difference between the forward and after draughts of s ship is called the ‘trim’, so that trim T=da- df, and as previously stated the ship will the said to be trimming by the stern or the bow according as the draught aft or the draught forward is in excess. For a given total load on the ship the draught will have its least value when the ship is on an even keel. This is an important point when a ship is navigating in restricted depth of water or when entering a dry dock. Usually a ship should be designed to float on an even keel in the fully loaded condition, and if this is not attainable a small trim by the stern is aimed at. Trim by the bow is not considered desirable and should be avoided as it reduces the ‘height of platform’forward and increases the liability to take water on board in rough seas. Freeboard Freeboard may be defined as the distance which the ship projects above the surface of the water or the distance measured downwards from the deck to the waterline. The freeboard to the weather deck, for example, will vary along the length of the ship because of the sheer of the deck and will also be affected by the trim, if any. Usually the freeboard will be a minimum at amidships and will increase towards the ends. Freeboard has an important influence on the seaworthiness of a ship. The greater the freeboard the greater is the above water volume, and this volume provides reserve buoyancy, assisting the ship to rise when it goes through waves. The above water volume can also help the ship to remain afloat in the event of damage. It will be seen later that freeboard has an important influence on the range of stability. Minimum freeboards are laid down
for ships under International Law in the form of Load Line Regulations (from"Naval Architecture for Marine Engineers"by W Muckle, 1975) Technical terms 1. principal dimension主要尺度 40. platform平台 2. naval architecture造船(工程)学 41. rough se 强浪,汹涛海面 3.造船工程(设计)师 42. seakeeping耐波性 4. length between perpendiculars(LBP)垂线间长 nce外形(观),出现 5. summer load waterline夏季载重水线 44 camber 梁拱 6. forward/after perpendicular首/尾垂线 round of beam梁拱 7. rudder post尾柱 45. weather deck露天甲板 8.stem首柱 46. drainage排水 9. rudder pintle舵销 47. upright正浮,直立 10. length over all(LoA)总长 48 at rest在静水中 11. overhang(水线以上)悬伸部分 49. accommodation居住舱,适应 12. bulbous bow球鼻艏 bilge radius舭(部)半径 13. length on the waterline(LwL)水线长 51 midship section船中剖面 14. amidship船中 ge 舭(部) 15. breath moulded型宽 53 rise of floor船底升高 16. breath extreme最大船宽 54 flat of keel龙骨宽 17. shell plating船壳板 55 at plate keel平板龙骨 18. rivet铆接 56. vertical center girder中桁材 19.weld焊接 57. bevel折射角,将直角钢改为斜角 20. strake(船壳板)列板 58 connecting angle联接角钢 21. fender护舷木 9 tumble home内倾 22. deck area甲板面积(区域) 60. sailing ship帆船 23. cross channel vessel海峡船 61. steel merchant ship钢质商船 24.port港口,船的左舷 62.bar棒,巴(气压单位) 25.sde舷侧(边) 63.rake倾斜 26.quay码头 64. draught吃水,草图,通风 27. depth moulded型深 65. even keel等吃水,正浮 28. plating of deck甲板板 66. trimmed by the stern/bow尾/首倾 29. base line基线 67 moulded draught型吃水 30. upper deck上甲板 68 extreme draught最大吃水 31. second deck第二甲板 69 bar keel棒龙骨 32. the uppermost continuous deck最上层连续甲板70. drawing”“吃水” 33. rounded gunwale圆弧舷边顶部 71 draught marks吃水标志 34. moulded line型线 2. merial unit英制单位 35. sheer舷弧 73 metric unit公制单位 36ends船端 74. spacing间距 37 deck line at side甲板边线 75 hogging中拱 deck at side line甲板边线 76. sagging中垂 deck at side甲板边线 77hel横倾 38 profile纵剖面(图),轮廓 78. dry dock干船坞 39 sheer forward/aft首/尾舷 79. fully loaded condition满载标志
for ships under International Law in the form of Load Line Regulations. (from “Naval Architecture for Marine Engineers” by W.Muckle, 1975) Technical Terms 1. principal dimension 主要尺度 2. naval architecture 造船（工程）学 3. 造船工程（设计）师 4. length between perpendiculars (LBP) 垂线间长 5. summer load waterline 夏季载重水线 6. forward/after perpendicular 首/尾垂线 7. rudder post 尾柱 8. stem 首柱 9. rudder pintle 舵销 10. length over all (LOA) 总长 11. overhang （水线以上）悬伸部分 12. bulbous bow 球鼻艏 13. length on the waterline （LWL）水线长 14. amidship 船中 15. breath moulded 型宽 16. breath extreme 最大船宽 17. shell plating 船壳板 18. rivet 铆接 19. weld 焊接 20. strake （船壳板）列板 21. fender 护舷木 22. deck area 甲板面积（区域） 23. cross channel vessel 海峡船 24. port 港口，船的左舷 25. side 舷侧（边） 26. quay 码头 27. depth moulded 型深 28. plating of deck 甲板板 29. base line 基线 30. upper deck 上甲板 31. second deck 第二甲板 32. the uppermost continuous deck 最上层连续甲板 33. rounded gunwale 圆弧舷边顶部 34. moulded line 型线 35. sheer 舷弧 36 .ends 船端 37 .deck line at side 甲板边线 deck at side line 甲板边线 deck at side 甲板边线 38 .profile 纵剖面（图），轮廓 39 .sheer forward/aft 首/尾舷 40 .platform 平台 41 .rough sea 强浪，汹涛海面 42 .seakeeping 耐波性 43 .appearance 外形（观），出现 44 .camber 梁拱 round of beam 梁拱 45. weather deck 露天甲板 46 .drainage 排水 47 .upright 正浮，直立 48 .at rest 在静水中 49. accommodation 居住舱，适应 50. bilge radius 舭（部）半径 5.1 midship section 船中剖面 52 .bilge 舭（部） 53 .rise of floor 船底升高 54 .flat of keel 龙骨宽 55. flat plate keel 平板龙骨 56 .vertical center girder 中桁材 57 .bevel 折射角，将直角钢改为斜角 58 .connecting angle 联接角钢 59 .tumble home 内倾 60 .sailing ship 帆船 61 .steel merchant ship 钢质商船 62 .bar 棒，巴（气压单位） 63. rake 倾斜 64 .draught 吃水，草图，通风 65. even keel 等吃水，正浮 66 .trimmed by the stern/bow 尾/首倾 67 .moulded draught 型吃水 68 .extreme draught 最大吃水 69. bar keel 棒龙骨 70 .”drawing”“吃水” 71.draught marks 吃水标志 72 .imperial unit 英制单位 73 .metric unit 公制单位 74. spacing 间距 75 .hogging 中拱 76 .sagging 中垂 77 .heel 横倾 78. dry dock 干船坞 79 .fully loaded condition 满载标志
80 freeboard干舷 83 ¨ stability稳性范围 81 seaworthiness适航性 84 Load Line regulations载重线规范 82, reserve buoyancy储备浮力 Additional Terms and Expressions 1l. center plane中线面 1. form coefficients船型系数 12. midstation plane中站面 2. block coefficient方型系数 13. moulded base line基线 3. prismatic coefficient棱型系数 4. length breadth ratio长度比 4. midship area coefficient船中横剖面面积系 15. cruiser stern巡洋舰型尾 16. principal coordinate planes主坐标面 5. waterplane area coefficient水线面面积系 方尾 数 18. soft chine圆舭 6. vertical prismatic coefficient竖向棱型系数 19. hard chine尖舭 7. body section of U- form U形横剖面 20. counter尾伸部 8.V- shaped section V形横剖面 21. forefoot首踵 9. geometrically similar ships几何相似船 22. aftfoot尾踵 10. base plane基平面 3. deadwood尾鳍(呆木) Notes to the text 1. as will be seen later和 as is the case in the length between perpendiculars中as引出的从句为非限制性定 语从句。关系代词as代替整个主句,并在从主语中作主语。as也可在从句中作宾语,表语用 2. A third length序数字前面,一般用定冠词“the”,但当作者心目中对事物总数还不明确,或还不足以 形成一个明确的序列时,序数字前面用不定冠词“a”。例 米, will they have to modify the design a fourth time?(它们的设计究竟要修改多少次,心中无数,但依 次下来已是第四次,所以用不定冠词“a”。) 3. This is the distance measured on the waterline at which the ship is floating from the intersection of the stern with the waterline to the intersection of the stem with the waterline 这是一个符合据。其中 at which the ship is floating为定语从句,修饰 the waterline. from the intersection of the stern( with the waterline为 Intersection所要求的介词短语) to the intersection of the stern( with the waterline为第二个 Intersection所要求的介词短语)都属于介词短语,作状语用,说明测量 的范围 4.参见第一课注3中的第二部分说明 5.quay一般指与海岸平行的码头 pier系指与海岸或呈直角面突出的码头 wharf一般用于的码头 6. the deck line continued和 the stern produced为过去分词作后置定语,分别修饰“ the deck line和the stern.都可译成“延长时”。 considerable variation was made from these standard values N departures were made from the parabolic sheer profile和(when) use is made of amidship draughts这三句都属于主语的成分被位于动词隔离成两部分。这 是英语句子结构平衡的需要中带有这种情况,阅读和翻译时需加以注意 7. considerable variation was made from these standard values Fl departures were made from the parabolic sheer profile和(when) use is made of amidship draughts这三句都属于主语的成分被位于动词隔离成两部 分。这是英语句子结构平衡的需要中带有这种情况,阅读和翻译时需加以注意
80 .freeboard 干舷 81 .seaworthiness 适航性 82 .reserve buoyancy 储备浮力 83 .range of stability 稳性范围 84.Load Line Regulations 载重线规范 Additional Terms and Expressions 1. form coefficients 船型系数 2. block coefficient 方型系数 3. prismatic coefficient 棱型系数 4. midship area coefficient 船中横剖面面积系 数 5. waterplane area coefficient 水线面面积系 数 6. vertical prismatic coefficient 竖向棱型系数 7. body section of U-form U 形横剖面 8. V-shaped section V 形横剖面 9. geometrically similar ships 几何相似船 10. base plane 基平面 11. center plane 中线面 12. midstation plane 中站面 13. moulded base line 基线 14. length breadth ratio 长度比 15. cruiser stern 巡洋舰型尾 16. principal coordinate planes 主坐标面 17. transom 方尾 18. soft chine 圆舭 19. hard chine 尖舭 20. counter 尾伸部 21. forefoot 首踵 22. aftfoot 尾踵 23. deadwood 尾鳍（呆木） Notes to the Text 1. as will be seen later 和 as is the case in the length between perpendiculars 中 as 引出的从句为非限制性定 语从句。关系代词 as 代替整个主句，并在从主语中作主语。as 也可在从句中作宾语，表语用。 2. A third length 序数字前面，一般用定冠词“the”，但当作者心目中对事物总数还不明确，或还不足以 形成一个明确的序列时，序数字前面用不定冠词“a”。例： will they have to modify the design a fourth time? (它们的设计究竟要修改多少次，心中无数，但依 次下来已是第四次，所以用不定冠词“a”。) 3. This is the distance measured on the waterline at which the ship is floating from the intersection of the stern with the waterline to the intersection of the stem with the waterline. 这是一个符合据。其中 at which the ship is floating 为定语从句，修饰 the waterline. from the intersection of the stern (with the waterline 为 intersection 所要求的介词短语)to the intersection of the stern(with the waterline 为第二个 intersection 所要求的介词短语）都属于介词短语，作状语用，说明测量 的范围。 4. 参见第一课注 3.中的第二部分说明 5. quay 一般指与海岸平行的码头 pier 系指与海岸或呈直角面突出的码头 wharf 一般用于的码头 6. the deck line continued 和 the stern produced 为过去分词作后置定语，分别修饰“the deck line 和 the stern .都可译成“延长时”。 considerable variation was made from these standard values 和 departures were made from the parabolic sheer profile 和（when）use is made of amidship draughts 这三句都属于主语的成分被位于动词隔离成两部分。这 是英语句子结构平衡的需要中带有这种情况，阅读和翻译时需加以注意。 7. considerable variation was made from these standard values 和 departures were made from the parabolic sheer profile 和（when）use is made of amidship draughts 这三句都属于主语的成分被位于动词隔离成两部 分。这是英语句子结构平衡的需要中带有这种情况，阅读和翻译时需加以注意