【正文】 (C=13 177。 pinion drive▼Installation of pression bars▼Installation of drain valves cleats etc.▼Installation of rolling stoppers and locking fittings▼Welding▼Operation and hose test▼Commissioning Checking of Coamings Before taking the hatch cover on board ,check and record the hatch coaming accuracy .Allowable tolerances are shown below .In case the required tolerances are not plied with corrective steps to be taken prior to taking the covers on the coaming. General tolerance of hatch coamingsThe center point is defined as the point of 1/2 of the hatch opening dimensions ,and the lines to connect the center points are defined as the center lines .see drawing as followIn case the longitudinal center line and transversal center line are not perpendicular,the longitudinal center line should be adjusted .Difference of the diajonal lines according drawing as follow Coaming with adjustable pression bar . L (m) t1（Standardmm） t2(MAX Limitmm) ≤ 3 3 5 (3)7 4 5 (7)13 5 10 (13)25 5 10 Tolerance of coaming plateAll the following tolerance are valid for a pleted coaming, which theoretically should be straight .the coaming shall be at uniform temperature when being measured .. Marking the Position of wheel Rails Mark the position of the rails on the coaming top using the actual dimensions taken from the wheels on the covers .Middle line of the hatch cover to be used as reference line . The longitudinal center line of the hatch to be used as reference line for all athwartships measurements .2. 6. Installation of Rails Installation the rails accurately on the fixing lines produced as per coaming .When installing the rails ,watch for the possible deformations in the rail bars .Start the installation at one end and tack weld it on the correct location .Provide an adjusting allowance at the ends of the rails for cutting the final slopes the wheels so that the specified clearance wheel/rail in closed position can be maintained This means that the last section of the rail shall be installed after having the covers on the coaming .l Do not weld the rails pletely before the first operational tests of the cover ! ! ! 2. 7. Taking Covers on board and Aligning on Coaming2. 7. 1 The hatch cover panels shall be lifted on the hatch coaming by using the eye plates on the top place any loose items or stand on the hungup cover .The pair of panels can be positioned by using a portable jack and chain block Place suitable steel liners under side and end plates before lifting the panels on coaming .The theoretical distance between coaming top and the side plate is 15 mm .2. 7. 2 .There are reference lines punched on the hatch covers during the fabrication procedure .Similar reference marks are to be punched on top of the hatch coaming before positioning of the hatch cover . The hatch cover is positioned so that reference marks on the panels are aligned with the marks on the coaming .the rubber packing pression at meeting joint is 13mm+5/3,whenthe distance between the punch marks is 200mm. 2. 8. Installation of the wedge Guides 2．8. 1 The wedge guides are to be installed after the hatch cover panels have been positioned correctly on the coaming . 2．8. 2 The wedges are used to push the panel to a position,where pression at packing between panels is 13mm(the distance between the punch marks on the cover top plate is 200mm) and to hold the panels in this position . 2．8. 3 Check the below items after installation of the wedges (wedges in contact with their counter pieces) 2．8. 3. 1 The distance between the punch marks on the cover top plate is . the packing of the meeting part is pressed by 13mm,when panels are resting on their supports. 2．8. 3. 2 The hatch cover center line is in correct position in relation to the coaming center .2