Single pull macgregor type hatch cover.pdf - Cochin University of ...

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in previous arrangement. Thus the number of heavy components to be lifted every time the hatch was opened and closed would have been reduced from eleven to four. Figure 1.1 Simplified arrangement of a traditional hatch Source: Cargo Access Equipment for Merchant Ships. This arrangement also had the advantage of being safer than the earlier one. As hatches became longer it becomes increasingly necessary to fit force and afters in several actions. These were more difficult to ship when battening down that those modes in one piece, since at least one end of each section had to be positioned on a seat attached to a traverse web before the hatch board could be put on. This meant that the man had to sit astride the web, over the open hold, to guide into place a very dangerous practice. Atharwdship hatch boards and fore and afters continued to be used well into 20 th century although the longitudinal arrangement gradually replaced them. After the implantation of the 1930 international load line conventions fore and after were only found in ships with very small hatches. 4
All types of wooden hatch were made watertight by means of tarpaulins and this method is still employed in those ships with traditional hatches that remain in service. The use of wooden hatch cover has declined throughout much of this century to the extent that it is now almost unthinkable that they should be fitted in modern vessel of any size. It is interesting therefore, to consider the reason for their demise. These fall into three broad categories, namely safety and security, cargo working and maintenance. 1.3 FAILINGS OF WOODEN HATCHES 1.3.1 Safety and Security It is impossible to exaggerate the importance and secure hatch covers; there can be no question that a ship’s survival may depend upon having them. But how efficient are wooden hatch covers? Tarpaulins are the most vulnerable component of traditional hatch covers. There are several common reasons for tarpaulin failure. Slackening of wedges is one of the most important factor. Chaffing is another serious source of weakness, especially at the coamings. Tarpaulins are also liable to suffer damage every time that they are removed for working cargo. Security of the wooden hatches also arose as a result of the comparatively large size of the hatchways of many of the ships, especially colliers, then entering service. Not only were the hatchways longer and wider than had been the customs up to that time, but the ratio of hatch width to overall beam was often greater too. This was particularly apparent in ships employed in the carriage of bulk cargoes and some of the most extreme examples were to be amongst self-trimming colliers where hatch width/ship beam ratios often exceed 0.6. Individual hatch boards were laid loosely on top of the beams in a normal hatchway and they could easily be shipped accidently. In order to prevent this, interlocking boards were developed. These could be handled manually in the usual manner but once landed on the beams; they were retained in place by a simple locking device which was claimed by its manufacturer to enhance the safety of a ship, should it lose its tarpaulins, by preventing the boards from being washed away by the sea. 5
Page 1 and 2: SINGLE PULL MACGREGOR TYPE HATCH CO
Page 3 and 4: ACKNOWLEDGEMENT First of all we hel
Page 5 and 6: TABLE OF CONTENTS v Page no. CERTIF
Page 7 and 8: 5.1.4 Hatch Covers Design. 58 5.1.5
Page 9 and 10: LIST OF FIGURES Figure no: Title Pa
Page 11 and 12: Figure7.10 Bulwark 84 Figure7.11 Bu
Page 13 and 14: CHAPTER 1 - INTRODUCTION The classi
Page 15: leakage can cause cargo damage and,
Page 19 and 20: The first horizontal rolling built
Page 21 and 22: CHAPTER 2 - TYPES OF HATCH COVERS M
Page 23 and 24: 2.1 SINGLE PULL 2.1.1 Description F
Page 25 and 26: 2.3 FOLDING & MULTI-TYPE 2.3.1 Desc
Page 27 and 28: 2.5 PIGGY BACK 2.5.1 Description Fi
Page 29 and 30: 2.7 REEFERS HATCH COVERS Figure 2.7
Page 31 and 32: CHAPTER 3 - GENERAL REQUIREMENTS 3.
Page 33 and 34: secured by tarpaulins and battening
Page 35 and 36: force by the 1967 Merchant shipping
Page 37 and 38: 3.2.2 Cover Stowage Where a designe
Page 39 and 40: It is also necessary to provide dra
Page 41 and 42: Other steel hatch cover secured wea
Page 43 and 44: Table 3.4 Access equipment strength
Page 45 and 46: Longitudinal deformation of the top
Page 47 and 48: (vii) It should retain all the abov
Page 49 and 50: easier to handle without power assi
Page 51 and 52: � Keep wheels, cleats, hinge pins
Page 53 and 54: 4.2.2 Drive Chains; Check their Len
Page 55 and 56: Figure 4.2 Vessel in rough weather
Page 57 and 58: Figure 4.5 Never smoke in a hold. S
Page 59 and 60: Figure 4.9 Always wear protective h
Page 61 and 62: e taken when opening hatch covers e
Page 63 and 64: Remember to carry out a chalk test
Page 65 and 66: 4.6.13 Painting Corrosion occurs ma
Page 67 and 68:
11. Coaming. 12. Sheave. 13. Cross
Page 69 and 70:
Breadth: 44.5cm 5.1.3 Hatch Coaming
Page 71 and 72:
Slope: 1cm Total number of panels:
Page 73 and 74:
Height of jack while normal conditi
Page 75 and 76:
Pulley for rope Diameter: 2cm Width
Page 77 and 78:
Height from the deck: 7.2cm Height
Page 79 and 80:
CHAPTER 6 - FABRICATION The design
Page 81 and 82:
6.3 HATCH COAMING FABRICATION Broug
Page 83 and 84:
Using wood cutter length of 320 cm
Page 85 and 86:
Plastic wheels (16 pieces), metalli
Page 87 and 88:
At the top of the iron plate, rail
Page 89 and 90:
Figure 6.12: Crane space Source: Te
Page 91 and 92:
CHAPTER 7-ASSEMBLY OF FABRICATED PA
Page 93 and 94:
Source: Team 7.3 ASSEMBLY OF SIDE D
Page 95 and 96:
7.6 ASSEMBLY OF HATCH COVER All the
Page 97 and 98:
The whole bulwark is placed over th
Page 99 and 100:
Through the middle top eye bolt rop
Page 101 and 102:
The test involves placing (with hat
Page 103 and 104:
CHAPTER 9 - CONCLUSION Right from t
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