Seamanship Techniques 2011 E Part 2 pps

40 361 0
Seamanship Techniques 2011 E Part 2 pps

Đang tải... (xem toàn văn)

Tài liệu hạn chế xem trước, để xem đầy đủ mời bạn chọn Tải xuống

Thông tin tài liệu

23The Ship years before seeing a bill through Parliament, in 1876, which resulted in the Merchant Shipping Act. The Act gave the Department of Trade and Industry, as we now know it, the right of inspection, to ensure that a vessel should not be overloaded beyond her Plimsoll mark or line. Samuel Plimsoll championed the improvement of conditions for the seafarer, and became the President of the Sailors and Firemens Union in his later years. Assigning a Vessel’s Loadline The assigning of a vessel’s loadline by the Department of Trade or other similarly approved assigning authority is carried out in accordance with the Loadline Rules, which were set and devised by the International Conference on Loadlines. The calculation regarding the freeboard and consequently the position of loadlines will be dependent on the type of vessel and its length, ships being divided into two types, ‘A’ and ‘B’. Type ‘A’ – Vessels designed to carry only liquid, bulk cargoes, e.g. tankers. Type ‘B’ – All other vessels not governed by the Type ‘A’ definition. The assigning of the freeboard will be governed by many factors and it is not within the scope of this text to detail the loadline rules. (Additional information is obtainable from Murray-Smith, ‘The 1966 International Conference on Loadlines’, Trans. R.I.N.A., 1969.) With the exception of pleasure yachts, warships and the like, all British ships and the majority of vessels of other maritime nations over 80 net registered tons are obliged to be marked with statutory loadlines, to ensure that they are not overloaded. Various authorities assign loadlines on behalf of the British Government, e.g. Det Norske Veritas (DNV), Lloyds Register (LR), Department of Trade (DT). A loadline certificate must be displayed in a prominent place aboard the vessel. The certificate is valid for five years, but an annual survey is Figure 1.32 Alternative tonnage marks. Positions and marks, not drawn to scale or 1080 mm if timber loadline assigned Marks may be white or yellow on a dark background as an alternative Diagram showing the relative position of the alternative tonnage mark in relation to the loadline disc. 300 mm All lines 25 mm thick Optional tonnage mark for fresh or tropical waters 300 mm TD 190 mm230 mm 190 mm 25 mm Assigned tonnage draught (TD) 540mm 1 48 th ‘Computer Software’ Many vessels now employ computer loading programmes to establish disposition of cargo, ballast and stores. Such software can be beneficial in producing the ships stability data, together with anticipated stress factors throughout the ships length. 24 Seamanship Techniques TF F T S W W Starboard side 450 mm 300 mm 540 mm 1 48 th LD FWA V N LTF LF Assigned lumber draught (LD) 230 mm 25 mm 230 mm All lines 25 mm LWN LS LT FWA LD LD Figure 1.33 Timber loadlines. held to ensure that the conditions of assignment and the loadline marks remain unchanged. Should the loadline be submerged through the overloading of the vessel, so contravening the regulations then the master or owner is liable to a fine of £1000.00 plus £1000.00 for every cm or part of 1 cm over- loaded. The upper edge of loadline marks are the recognised mark levels. The loadline itself (Figure 1.31) is punched into the shell plate and painted a distinctive colour, usually white or yellow on a dark background. Owners of vessels may make application to the Maritime and Coastguard Agency for a vessel to be assigned an alternative tonnage. Gross and registered tonnages are assigned not only for the upper deck but also for the second deck, excluding the ’tween deck space, so treating the second deck as the upper deck level. Once an alternative tonnage has been assigned the tonnage mark (Figure 1.32) will be carved on each side of the vessel below the second deck and aft of the loadline disc. Should the vessel be so loaded as to submerge the alternative tonnage mark, then the normal gross and registered tonnage will apply. Should the state of loading leave the mark visible, then the modified tonnage values will remain valid. 1 48 th 1 36 th LW 2 ANCHOR WORK With the many different types of vessel employed in the marine industry, it is only to be expected that anchors and their associated equipment have changed considerably over the years. From the forerunners used by the ancient Greeks to the present day, purpose and design have been dictated by the needs of the industry. ANCHORS Admiralty Pattern Anchor Sometimes referred to as a ‘fisherman’s’ anchor, this design is still popular within the fishing industry (Figure 2.1(a)). It has been in use for many years, but because it has difficult stowage characteristics, e.g. it cannot be stowed flat with the stock in position, it has been followed by more manageable designs. Once let go, the stock, lying at right-angles to the direction of the arms/flukes, causes a fluke to dig into the sea bed. This leaves the remaining fluke exposed, and the cable may often foul it when the vessel swings. When the anchor is not in use, the forelock in the stock can be unshipped, permitting the stock to be stowed parallel to the shank. The holding power of this anchor is generally considered to be very good indeed. The design is such that the stock is longer and heavier than the arms. This lends itself to the theory that the stock will be dragged flat along the sea bed, causing one of the flukes to bury itself. The angle of the stock would also be expected to turn the flukes in the direction of the sea bed as the anchor strikes the bottom. It is interesting to note that the longer the shank on these anchors the better it holds. The weight of the stock must be equal to 25 per cent of the weight of the anchor itself. Some stocks are designed straight if the weight of the anchor is over 12 cwt (610 kg), but a bent stock, as indicated in Figure 2.1(a) would be encountered on anchors below this weight. The holding power of this common anchor will be, roughly speaking, three to four times its weight, depending on the nature of the sea Shank Gravity band Forelock Stock Fluke Arm Crown Pea or bill (a) Shank Hollow fluke Knuckle Hinge pin Stops (b) Figure 2.1 Admiralty pattern anchor (above) and (below) Admiralty cast anchor type 14 (AC14). 26 Seamanship Techniques Shank Stock bottom. It is unlikely to be seen on board merchant vessels, except possibly as a lifeboat anchor or as a kedge anchor. The weight in any event would rarely exceed two tonnes. The Stockless Anchor This is by far the most popular anchor in general use today its principal parts are shown in Figure 2.2. The head of the anchor is secured to the shank by a hinged bolt which allows the arms to form an angle of up to 45° with the shank. Further rotation of the arms are prevented by the head meeting the shank, at the built-in stops. The head of the anchor is comprised of the flukes, the arms, and the crown which are manufactured from cast steel, whereas the shank is made of cast steel or forged iron. The hinge bolt and the shackle are made of forged iron. The stockless anchor’s greatest advantage is its close stowing properties and is easily housed in the hawse pipe when not in use. It is easily handled for all anchor operations, and made anchor beds (used with the close stowing anchor) obsolete. The overall size of these anchors will vary between individual ship’s needs but the head must be at least three-fifths of the total weight of the anchor. Holding power again varies depending on the nature of the bottom but, as a rule of thumb, it may be considered to be up to three times its own weight. The mariner should be aware that the rotation action of the moving arm may cause the anchor to become choked when on the sea bed so that the arms/flukes are not angled to the full amount and therefore losing the holding power effect. Admiralty Cast Anchor Used extensively as a bower anchor for warships, this anchor, because of good holding properties, is becoming very popular with the merchant service (Figure 2.1(b)). With the increase in size of ships – the large tankers of today, for example – shipowners required an anchor with greater holding power. The AC Type 14, as it was called, was developed in the United Kingdom and has the required properties. Tests showed that it had more than twice the holding power of a conventional stockless anchor of the same weight. With such an obvious advantage, Lloyds Classification Society granted a 25 per cent reduction in regulation weight. The holding properties of this anchor are directly related to the fluke area, the angle of which operates up to 35° to the shank. The angle of the flukes is made possible by a similar operation as with the stockless anchor, in which a hinge pin passes through the shank in the crown of the anchor. CQR Illustrated in Figure 2.3, the CQR sometimes referred to as a ‘Plough- share’ anchor or, in the United States, just as a plough anchor. It is generally used as a mooring anchor, especially for the smaller type of vessel. Holding power is again dependent on the type of ground that the Head of the anchor Fluke Arm Anchor crown shackle Shank Tripping palm Pea or bill Crown Figure 2.2 Hall stockless anchor. Figure 2.3 CQR anchor (above), Danforth anchor (below). 27Anchor Work anchor is bedding into but has been found to be very good. It also has extremely good resistance to drag. Like the Admiralty Pattern, it is difficult to stow. The design has been modified since its invention to incorporate a stock, and is often used as a mooring anchor (Figure 2.28(b)). The CQR was a British invention by scientist Sir Geoffrey Taylor, who was a man with little boating experience. The invention showed that the application of basic principles can sometimes improve on practical experience. Small-boat owners tend to have the choice of two anchors on the market, namely the Danforth and the CQR. Both anchors have reasonable holding power but the Danforth may have a tendency to drag whereas the CQR will not. For easier handling and stowing the Danforth would be more popular, but if it is decided to use an anchor for the job it was meant for, preference is generally given to the CQR. Danforth Anchor Generally accepted as a small-boat anchor, this anchor dominates the American boat market (Figure 2.3). A stock passes through the head of the anchor, allowing it to be stowed easily in a similar manner to the stockless anchor. Holding power is about 14.2 times its own weight. The anchor is of American design, and the idea of the stock being passed through the crown of the anchor as opposed to the top of the shank demonstrates a practical solution to the stowage problem. The stock in this position prevents the anchor being fouled on its own cable. Holding properties are good but not as good as the CQR’s, and it has a tendency to drag or glide until the flukes bite into the sea bed. The action of this anchor is similar to that of the stockless anchor, where the tripping palms catch and cause the flukes to be angled to the shank. With the Danforth anchor, the tripping palms are generally situated closer to the centre line of the anchor. Once tripped, the spade-shaped flukes will tend to dig into the bottom. TESTS ON ANCHORS All anchors over 168 lb (76 kg) in weight must be tested and issued with a test certificate. The weight of any anchor for the purpose of the rules and regulations governing anchors and cables shall: (a) for stockless anchors include the weight of the anchor together with its shackle if any, and (b) for stocked anchors, the weight of the anchor including its shackle, if any, but excluding the stock. Drop Test (cast anchors) Any part of an anchor over 15 cwt is subjected to a percussion test by being dropped both end on and side on from a height of 12 ft on to an iron or steel slab. After that, the piece must be slung and hammered all over by a 7 lb sledgehammer. A clear ring must be produced to show that no flaw has developed during the percussion test. 28 Seamanship Techniques TABLE 2.1 Proof loads for anchors Weight Proof Weight Proof Weight Proof Weight Proof Weight Proof Weight Proof of load of load of load of load of load of load anchor anchor anchor anchor anchor anchor ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— Kg Tonne Kg Tonne Kg Tonne Kg Tonne Kg Tonne Kg Tonne ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 76 3.33 700 15.20 2300 39.60 4700 65.10 7200 82.60 15000 117.70 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 80 3.46 750 16.10 2400 40.90 4800 65.80 7400 83.80 15500 119.50 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 90 3.70 800 16.90 2500 42.20 4900 66.60 7600 85.00 16000 120.90 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 100 3.99 850 17.80 2600 43.50 5000 67.40 7800 86.10 16500 122.20 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 120 4.52 900 18.60 2700 44.70 5100 68.20 8000 87.00 17000 123.50 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 140 5.00 950 19.50 2800 45.90 5200 69.00 8200 88.10 17500 124.70 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 160 5.43 1000 20.30 2900 47.10 5300 69.80 8400 89.20 18000 125.90 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 180 5.85 1050 21.20 3000 48.30 5400 70.50 8600 90.30 18500 127.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 200 6.25 1100 22.00 3100 49.40 5500 71.30 8800 91.40 19000 128.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 225 6.71 1150 22.80 3200 50.50 5600 72.00 9000 92.40 19500 129.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 250 7.18 1200 23.60 3300 51.60 5700 72.70 9200 93.40 20000 130.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 275 7.64 1250 24.40 3400 52.70 5800 73.50 9400 94.40 21000 131.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 300 8.11 1300 25.20 3500 53.80 5900 74.20 9600 95.30 22000 132.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 325 8.58 1350 26.00 3600 54.80 6000 74.90 9800 96.20 23000 133.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 350 9.05 1400 26.70 3700 55.80 6100 75.50 10000 97.10 24000 134.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 375 9.52 1450 27.50 3800 56.80 6200 76.20 10500 99.30 25000 135.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 400 9.98 1500 28.30 3900 57.80 6300 76.90 11000 101.50 26000 136.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 425 10.50 1600 29.80 4000 58.80 6400 77.50 11500 103.60 27000 137.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 450 10.90 1700 31.30 4100 59.80 6500 78.20 12000 105.70 28000 138.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 475 11.40 1800 32.70 4200 60.70 6600 78.80 12500 107.80 29000 139.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 500 11.80 1900 34.20 4300 61.60 6700 79.40 13000 109.90 30000 140.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 550 12.70 2000 35.60 4400 62.50 6800 80.10 13500 111.90 31000 141.00 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 600 13.50 2100 36.90 4500 63.40 6900 80.70 14000 113.90 ——— ——— ——— ——— ——— ——— ——— ——— ——— ——— 650 14.30 2200 38.30 4600 64.30 7000 81.30 14500 115.90 Proof loads for intermediate weights shall be obtained by linear interpolation. 29Anchor Work The Bending Test (cast anchors) An additional piece of metal, 20 cm long, is cast with the piece to be tested, and is cut away for the purpose of the bending test. This piece will be turned down to 2.5 cm in diameter, and bent cold by hammering through an angle of 90° over a radius of 3.75 cm. The casting will be deemed sufficiently ductile if no fracture appears in the metal. All anchors are subject to the proof strain (Table 2.1), and subsequent proof load, but only cast steel anchors will be subjected to percussion, hammering, and bending tests. Wrought iron, or forged steel anchors are not subjected to these tests as they are forged from red hot slab by hammering. All other anchors will also be annealed. MARKS ON ANCHORS Each anchor must carry on the crown and on the shank the maker’s name or initials, its progressive number, and its weight. The anchor will also bear the number of the certificate, together with letters indicating the certifying authority (Figure 2.4). ANCHOR CERTIFICATE After the test on the anchor is completed, an anchor certificate will be awarded. The certificate will show the following: Type of anchor. Weight (excluding stock) in kilogrammes. Weight of stock in kilogrammes. Length of shank in millimetres. Length of arm in millimetres. Diameter of trend in millimetres. Proof load applied in tonnes. Identification of proving house, official mark and government mark. Number of test certificate. Number of tensile test machine. Year of licence. Weight of the head of the anchor. Number and date of drop test. CHAIN CABLE TESTS Anchor cable over 12.5 mm in diameter is accepted for testing at an approved testing establishment in lengths of 27.5 m. (1 shackle of cable). The manufacturer will provide three additional links for the purpose of the test. These three links will be subjected to a tensile breaking stress, and if this proves to be satisfactory, then the total length of the cable will be subjected to a tensile proof test, the tests being carried out on approved testing machines. If two successive links break, the cable is rejected. Before the test on chain cable is carried out, the supervisor will satisfy Figure 2.4 Marks on cable. X (certificate Number); YYY (certifying Authority). X Y Y Y 30 Seamanship Techniques himself that the quality of the material from which the cable is manufactured meets with the requirements of the anchor and chain cable regulations. After a successful test on chain cable a certificate is awarded, stating: Type of cable. Grade of cable. Diameter in millimetres. Total length in metres. Total weight in kilogrammes. Length of link in millimetres. Breadth of link in millimetres. Tensile breaking load applied in tonnes. Tensile proof load applied in tonnes. Number and types of accessories included. The certificate issued shall also show: A serial number. Name of the certifying authority. Mark of the certifying authority. Name of the testing establishment. Mark of the testing establishment, if any. Name of the supervisor of tests. The certificate is signed on behalf of the certifying authority. NOTES ON CABLE Accessories Anchor shackles, and joining shackles are all ordered together with any additional fittings for the size of cable they are intended to work and be associated with. These accessories must be subjected to similar tensile load and proof load tests as the cable. Material of Manufacture Wrought iron, forged mild steel, cast steel, or special quality forged steel are used. Wrought iron is weaker than the other three materials, and is expensive to produce; consequently it is rarely seen on present-day merchant ships. Types of cable are shown in Tables 2.2 and 2.3. Size of Cable The size is measured by the diameter of the bar from which the link is manfactured. Aboard a vessel the size could be obtained from the chain cable certificate, or callipers could be used to measure the actual cable. KENTER LUGLESS JOINING SHACKLE The Kenter Lugless Joining Shackle, manufactured in nickel steel, is the most popular method of joining shackle lengths of the anchor cable together. The shackle has four main parts, as shown in Figure 2.5. The 31Anchor Work TABLE 2.2 Types of chain cable 27.5 m = 15 fathoms = 1 shackle length Grade Meterial Method of manufacture Tensile range kg/mm 2 1a Wrought iron Fire welded 31–41 1b Mild steel Fire welded 31–41 1c Mild steel Flash butt welded 31–41 1d Mild steel Flash butt welded 41–50 2a Steel Flash butt welded or drop forged 50–65 2b Steel Cast 50 min 3a Steel Flash butt welded or drop forged 70 min 3b Steel Cast 70 min TABLE 2.3 Stud link chain cable Diam. I (U1) II (U2) III (U3) Minimum weight mm Proof Break Proof Break Proof Break per shackle length 12.5 4.7 6.7 6.7 9.4 9.4 13.5 0.105 50.0 70 100 100 140 140 200 1.445 60.0 98.8 141 141 198 198 282 2.075 70 132 188 188 263 263 376 2.85 90 209 298 298 417 417 596 4.705 122 357 510 510 714 714 1019 8.55 152 515 736 736 1030 1030 1471 13.20 Figure 2.5 Kenter lugless joining shackle. Shackle broken Dovetail recess chamber Stud Lead pellet Shackle assembled two main halves interlock with the stud forming the middle of the link. All parts are held together with a tapered spile pin. This spile pin is made of steel and is driven into the shackle on the diagonal. A lead pellet is then forced into the inverted dovetail recess to prevent the pin from accidentally falling from the shackle. The manufacture of the shackle in nickel steel prevents corrosion and the parts becoming frozen together. It allows the shackle to be ‘broken’ with relative ease when either the cable is to be end-for-ended or shackles are to be tested. When breaking the shackle, remove the spile pin by using a punch and drift (Figure 2.15). If the lead pellet has not been prised out first, be careful that it is not forced out by the percussion effect of the drift driving the spile pin, for it may emerge with considerable force. A back stop should be provided to prevent persons being injured by the lead pellet being expelled from the recess. Once the spile pin is removed, the stud can be extracted; the two halves of the shackle can then be separated by means of a top swage obtained from the manufacturer. When the shackle is reassembled, care must be taken to ream out the dovetail recess, so that no residual lead is left inside. Should this not be done, then the next lead pellet inserted will not spread out and obtain a grip inside the recess. The construction of the Kenter shackle is such that it is larger than Spile pin 32 Seamanship Techniques the common links but not by so much that it will not fit into the snug of the gypsy of the windlass or cable holder. However, care should be taken that it does not lie flat on the gypsy and cause jamming. The main advantage of this type of joining shackle is that open end links are not required, as with the ‘D’ lugged joining shackle. In addition, all shackle lengths are the same, which ensures smoother working in the snugs of the gypsy. The shape of the Kenter lends itself to cable working, especially around and over the bow, and the tendency for it to catch is comparatively rare. As with other accessories, these shackles are tested, but because of their type of manufacture in nickel steel, they are not heat-treated. ‘D’ LUGGED JOINING SHACKLE The ‘D’ lugged joining shackle is used extensively for joining the cable to the anchor in more modern vessels. In the past this type of shackle was used, as the Kenter lugless joining shackle is used today, in the joining of the shackle lengths of cable together. If it is to be used for this purpose, the rounded crown part of the shackle should always face forward, so that it does not foul the anchor when letting go. It should be noted that the anchor crown shackle and the ‘D’ joining shackle face the opposite way to all other ‘D’ joining shackles in the cable. The mariner should be aware that the anchor, together with the initial joining shackle, is walked out of the hawse pipe prior to letting go (except in some cases of emergency). Consequently, the anchor crown shackle would not foul, but should other joining shackles be facing in this manner, there would be a distinct possibility of the lugs of the shackle catching on a snag in the letting-go operation. When using these types of shackle between cable length, each cable length must have an open link at the ends. This is necessary to allow the passage of the lugs through the cable. The construction of the ‘D’ lugged joining shackle is illustrated in Figure 2.6, where it may be seen that the bolt, generally oval in shape, is passed through the lugs and across the jaw of the shackle. A tapered spile pin of steel, brass or wood holds the bolt in position, a lead pellet being hammered home into a dovetail recess chamber to keep the spile pin from accidently being expelled. The spile pin should be tapered to a ratio of 1:16, and wooden pins are made of ash or solid bamboo. When breaking the ‘D’ joining shackle, the bolt will be hammered from the unlipped end, causing the wooden spile pin to shear. Should the spile pin be made of steel, then this must be expelled by using a punch and drift in a similar manner to that described for the Kenter shackle. The steel pin is generally found in the ‘D’ shackle joining the anchor cable to the anchor. When assembling these shackles, it is customary to give the bolt a smear of tallow to allow easy ‘breaking’ at a later date. Should the shackle become jammed and difficult to break, then it can be heated about the lugs. This will cause the lugs to expand, allowing the withdrawal of the bolt. Figure 2.6 ‘D’ lugged joining shackle. Crown Clear Lead pellet Tapered spile pin Bolt Dovetail chamber Jaw Lug [...]... cable with this cargo runner wire This turn should be made in the opposite direction to the foul turns in the cables 51 52 Seamanship Techniques 6 7 8 9 10 Pass the end of the wire messenger up through the hawse pipe of the sleeping cable and secure it to the end of the sleeping cable Heave away on the wire messenger, and at the same time ease out on the easing wire, heaving the end of the sleeping... should be removed from the cable, together with any lashings which may have been applied inside the cable locker Past and Present Practice A lashing in the cable locker served to stop the cables banging together when the ship was at sea In bygone days the sailors used to sleep in the fo’c’sle head area, and the banging cables tended to keep them awake Hence they were lashed secure The more up-to-date thinking... cable Figure 2. 24 not impossible.The method indicated in Figure 2. 24 shows an alternative to rigging recovery tackle as described This method eliminates the use of overhauling gear and reduces the time to effect recovery However, the system could only be employed on certain conventional vessels equipped with lifting gear forward Figure 2. 24 shows that the operation is rigged for the topping lift of the... Compressor (Guillotine bar) bow stopper CABLE HOLDERS Cable holders (Figure 2. 16) are often fitted to large merchant vessels as an alternative to the windlass, and, with recent developments, may be seen on passenger vessels They have also been popular with warships for some considerable time because they are compact and lie low on the deck Early models employed a cable drum (gypsy) without the valuable... splay apart Alternative Method A method mainly employed by the Royal Navy was to use two wires, one from each bow, as messengers about the fouled cables This method is effectively the same as the one described, but the use of two wires tends to expedite the work Clearing a Foul Hawse – Procedure (Figure 2. 22) 1 2 3 4 5 Heave up on both cables to bring the foul turns above the water and lash both cables... to detach the anchor from the cable, either for mooring to a buoy or for towing operations, where the bare end of cable is required The method of obtaining the bare end of cable was associated with ‘catting the anchor’, where a vessel was equipped with a ‘clump cathead’ A modern vessel will either be able to detach the cable while leaving the anchor secured in the hawse pipe or it will become necessary... Work SECURING AND STOWAGE OF ANCHORS Alternative methods of securing anchor to cable are illustrated in Figure 2. 7, and the operation of the cable in anchoring in Figure 2. 8 There are many different designs of hawse pipe (Figure 2. 9) in commercial use with the modern merchant vessel and the warship.The general arrangement is such that the axis of the pipe does not exceed 45° from the vertical; however,... together below the turns with a natural fibre lashing This lashing will prevent the turns from working themselves further down the cable Pass a wire preventer around the sleeping cable, down from the turns.This will reduce the weight on the turns, and serve to secure the sleeping cable should the end be lost This preventer should be passed in such a manner that it may be slipped from the deck when the... letting go.The Bridge should be informed that the anchor is on the brake of the windlass, or cable holder, and is ready for the order to ‘let go’ The engines should be operated to give stern way to the vessel The Master should check overside and see the stern wake, about half-way up the vessel’s length, and know that stern way is being made through the water, before giving the order to ‘let go’ The... remainder of cable Forepeak of vessel ‘D’ Hawse pipe (tubular steel) ‘D’ represents the diameter of the hawse pipe and is at least nine times the chain diameter Cable locker Shell plate Figure 2. 9 Arrangement of hawse pipe 34 Seamanship Techniques STEAM WINDLASS OPERATION PORT Bulkhead Bulkhead stiffening Split pin to prevent accidental removal of retaining pin Open link Anchor cable The following is a . ’tween deck space, so treating the second deck as the upper deck level. Once an alternative tonnage has been assigned the tonnage mark (Figure 1. 32) will be carved on each side of the vessel below. be provided to prevent persons being injured by the lead pellet being expelled from the recess. Once the spile pin is removed, the stud can be extracted; the two halves of the shackle can then. ‘broken’ with relative ease when either the cable is to be end-for-ended or shackles are to be tested. When breaking the shackle, remove the spile pin by using a punch and drift (Figure 2. 15). If the lead

Ngày đăng: 11/08/2014, 21:21

Từ khóa liên quan

Tài liệu cùng người dùng

Tài liệu liên quan