15 August 2002
Receiving Hose Connections. Space the receiving hose connections
approximately 45.8 m (150 ft) on centers. The 45.8 m (150 ft) spacing may be varied to
suit docking conditions in a specific drydock. Locate the hose connections between the
edge (coping) of the graving dock and the crane track to eliminate any interference with
the operation of the cranes. Make each connection 101.6 mm (4 in) diameter and install
an in-line check valve to prevent backflow.
Laterals. Laterals between the receiving hose connections and the main
sewer must have a diameter of 101.6 mm (4 in.) Where possible, the laterals should be
located in the drydock service and pipe galleries to minimize installation costs and to
facilitate maintenance. Pitch laterals to drain to the main sewer. Consider local
conditions for the optimum location of the laterals.
Main Sewers. Size main sewers to receive ship discharges plus any
other flow entering into the collection system. Main sewers should be located in the
pipe galleries or beyond the structural concrete of the graving dock. Consider local
conditions for the optimum location of the main sewers. Main sewers should be gravity
sewers and slope toward the inboard end of the dock and connect to the station sewer
system or to a pump lift station. Use a force main where it is impracticable to install a
gravity sewer. Locate sewer cleanouts in the main sewers at a maximum spacing of
91.44 m (300 ft.)
Ship-to-Dock Transfer System. Ships outfitted with Collection, Holding,
and Transfer (CHT) systems discharge sewage under pressure on the lowest weather
deck. Ships not outfitted with CHT systems will discharge through existing outlets in the
hull. For ships not outfitted with CHT systems, a temporary system for collecting
sewage from multiple outlets must be installed.
8-18.104.22.168.1 Auxiliary Pumping. Gravity drydock sewer systems may require auxiliary
pumping when the ship's discharge point is below the level of the top of drydock wall.
The facilities required for auxiliary pumping include hose, portable wet well, and pump.
Use a 101.6-mm (4-in) sewage hose to transfer sewage from the ship or portable
pumping unit to the drydock sewer system. Refer to Figure 8-2.
8-22.214.171.124.2 Collection System and Components. The temporary collection system
for ships not outfitted with CHT system, and the auxiliary pumping system components,
are collateral equipment to be furnished by the shipyard.
Industrial Wastewater Collection. Collect and treat industrial
wastewater, including runoff and hydrostatic leakage that come in contact with industrial
waste, such as sand blasting grit and organotin paint chips, as necessary, prior to
discharge. Refer to MIL-HDBK-1005/9A, Industrial and Oily Waste Control. See
section 7-1.1.3, for additional requirements.