Biennial rate contract for carrying out the various underwater works and desilting of dock gate housing pit in connection with docking and undocking of vessels in CSL

Underwater desilting work including removal of silt, mud, payal, other foreign matters etc from the repair dock gate housing pit to the required depth for lowering the dock gate using departmentally supplied airlift pump, pontoon, compressd air, water jet machine, air hoses etc. The mud shall be removed from the areas like bottom of buoyancy tank area of gate upto hinges [L=47.60m, bottom concrete level= -9.80m (from chart datum)], sloped area between hinges & pit [L=47.60m, B=5.40m, bottom concrete level= -9.80 to -11.30m (from chart datum)], pit sill [L=47.60m, B=1.10m, bottom concrete level= -11.30m (from chart datum)]& pit [L=47.60m, B=9.0m, bottom concrete level= -12.85m (from chart datum)] based on the draft required for the docking/undocking vessels. The materials pumped out from the pit are to be discharged well away from the entrance and quay wall. The rate quoted shall include charges for diver, hire charges for diving equipment, insurance for divers etc. The work shall be carried out as directed by the Engineer-in-Charge.(Payment shall be made based on initial & final soundings for the respective depths/ depth of gate lowering whichever is lower. Rate shall be quoted per metre depth of desilting)

desilting from the existing bed level to a level of 11.30m for lowering the dock gate to a depth of 7m (top width of gate is 4.30m. All levels are from chart datum)

desilting from a depth of 11.30m to 12.30m for lowering the dock gate to a depth greater than 7m upto 8m (All levels are from chart datum)

desilting and pumping out of fresh mud accumulated inside the gate housing pit i.e; from the existing level to the required level. (This Item will be operated if the previous desilting is done within 15 days)

Underwater operation for removing bolts & pins of props for lifting the No.II dock gate and props & putting back the above pins and bolts in the respective positions for refixing the props & gates in the original position including clearing the sill off any foreign materials obstructing the proper seating of gate etc. complete all as directed by the Engineer-in-charge. (Due to unavoidable reasons, the refixing of the gate may get delayed by 2 or 3 days after undocking/docking of vessels. In such cases also the contractor should be prepared to arrange the work without any extra claim).

Deployment of divers for arresting of leaks during flooding on one side of dock using intermediate gate. The divers shall inspect the gate prior to dock flooding and conceal the gap between gate and rubber beading using cotton wastes. They shall be available at site during the flooding activity to arrest any sudden/ unusual leakage during flooding. Only after the completion of flooding and ensuring that the leakages are minimized, they shall leave the site. The rate shall be inclusive of cost of diving, collection of cotton waste from departmental store and other incidentals etc. complete all as per the direction of Engineer-in-Charge.

Deployment of one diver along with an additional diver (for diving assistance/leadline) at a time.

Deployment of one diver along with an additional diver (for diving assistance/leadline) at a time.

Fixing the departmentally supplied sacrificial anodes at depths varying from 1.00m to 5.00m from chart datum fixed on sheet piles using SS bolts & washers at Quay-1, Quay-2, Quay-3 and dock entrances along the Quay side of CSL. The rate quoted should be inclusive of cost of all labour, Cost of bolts & washers, hire for tools, plants & equipments, transporattaion of anode from store to site, all other incidentals etc. complete. all as instructed by the Enginer- in- charge. (Sacrificial anodes will be issued by department free of cost.)