indentations,sea chest anchor and chain etc

1             a)   Describe possible faults which may be found during a dry dock inspection of the following and the remedial action taken.

1. Hull indentations                   
2. Anchor and chain                   
3. sea chest                              

hull indentations-

the primary factors to be considered in assessing the effect of indents are as follows

• measure the area and depth od the indentation and record in shell expansion drawing check Whether internal structural members in way.

• Whether internals in way are significantly affected i.e. tripped or adrift from bottom plating. Smooth sccttered indent with small depth with the internals remain intact can be left after the recording. If the depath is large renewal of the section with the similar plate having minimum 300x300mm  should be done any damaged or detached internals must be renewed.

 Anchor and chain

Identification of repairs are done after laying in dock bottom. Washing ,removal of any rust makes it easier for the inspection and caliberation

If the wear down is exceeded the recommended value those chain length are to be renewed with similar chain lengths with classification certificates .

Any missing lugs are to be replaced and loose lugs are to be re welded  joining shakeles securing arrangement and the pin and their end sealing arrangement with lead is checked

Anchor is checked for worn out fluke pin worn out shank pin and hole weight measurement is requirement in some classification societies

A           Steam outlet pipe section inside the sea chest corroded and wasted

B.             Pipe connecting the sea chests are thinned down or erroded (stub pieces are thinned down )

C.               Usually vent pipe is find chocked due to the small pipe diameter  the pipe get chocked

D.             In high sea sucion  upper area corrosion due to the accumulated air in the sea chest may find if the vent               holes are not provided on the top

E.           Sea chest top plates from the engine room side may get thin down due to the water leakages of glands and        accumulated water.

F.            Fouling

G.            Mgps sytem not funtioning

lll          locking arrangements of the gratings   wasted anodes   

 thhic  thickness measurement of sea chest plats and stub pieces should be done overhauling all opening mounted on the sea chest is done steam discharge line should be check anodes fitted are renewed. securing arrangements of the gratings are checked and ensure anodes are uncovered before fitting back the gratings.

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hull plate renewal

1     As a chief officer write a dry dock specification for the repair for the repair of following damage that has occurred, stating what factors must be considered when costing the repairs.” approx. 2 meters of damage to Forepeak tank shell plating must be removed and replaced along with relevant damaged stiffeners. In your specification, include the services required, accessory work required and final tests required to ensure satisfactory completion of the repair. 

Steel renewal in no fore peak  ballast tank

Please quote for following scope of work to be carried out during the period of dry docking 

tank capacity 5000 m³(sea water)

open manhole covers 02 nos on deck size 680mmX480mm for the inspection and to be boxed back after the repair with new jointings indicate repair cost for replacement of studs.

provide ventilation blowers for the tank during repair indicate cost per day

provide lighting to the tank

provide man entry certificate and hot work permit during the period of repair

clean the ballast tank and hose down prior to commencement of the repair

erect staging from frame no 46 to 51 at second stringer level to required height and to remove on completion

erect staging from frame no 46 to 51 for the outside shell on port side to 8meter height from ships baseline and to remove on completion

crop and renew the damage section of approx.; 02 square meters side shell plating with damaged frames in way of the plating area with classification approved materials. the material specification andthickness is clealy marked on the shell expansion drawing provided and details of the frames are included in the drawing for preparation.

Marerials certificates welding procedure and qualified welders are to be provided during the repair

work to be completed to the satisfaction of the classification society surveyor

on completion of the plate renewl vaccum test or hose test to be done on the plates.

Apply paint scheme   with inside the tank as per the attached specification

Paint supplied by ship

Outside the hull apply the yard supplied paint two coats of anticorrosive and anti-fouling paint coating thickness 300 microns are to applied paint supplied should have anti fouling approval certificate

Clean all debris generated during repair from the tank 

Tank will be pressure tested by ship staff on completion of the repairs by filling with sea water

Al above wok to be carried out to the satisfaction of the classification society surveyor