EPA's Vessel General Permit and Small Vessel General

include controllable pitch propellers, rudder bearings and wire ropes and cables that have
lubricated (greased) surfaces which are submerged in seawater during use. EPA analyzed the
risk of this discharge in its BE due to the high number of vessels discharging, the large volume
and frequency of discharges, along with the potentially high risk posed by the concentration and
types of pollutant discharged.
Table 20 shows the vessel sizes and the estimated stern tube packing gland discharge rates for
the vessel types requiring detailed analysis. Flows range from as little as 2 gal/day for
commercial fishing vessels to as great as 4,000 gal/day for large cruise ships.
Table 20. Estimated Stern Tube Packing Gland Effluent Discharge Rates used in EPAs
BE.
Vessel Type
Vessel Size
(gross
tons)a
Estimated Stern Tube
Packing Gland Effluent
Discharge Rates
m3/day gallons/day
Barges 705 0e 0e
Cargo/Bulk Carriers 15,939 4.5 1,195
Commercial Fishing 25b 0.008 2
Large Cruise Ships 53,526 15.1 4,014
Medium Cruise Ships 4,584 1.3 343
Large Ferries 1,451 0.4 108
Oil and Gas Tankers 24,908 7.1 1,868
Passenger Vessels (e.g., water taxis, tour
boats) 35c 0.01 2.6
Utility Boats (tugs and tow boats) 80d 0.02 6
a) Vessel size from EPA’s NOI Report (USEPA, 2011e) unless otherwise specified.
b) Vessel gross tons estimated assuming 50% of commercial fishing vessels are 40 feet long
(USEPA, 2010).
c) Vessel gross tons estimated assuming 50% of passenger vessels are 45 feet long (USEPA, 2010).
d) Vessel gross tons estimated assuming 50% of utility vessels are 65 feet long (USEPA, 2010).
e) Barges do not have propeller shafts and associated stern tube packing glands.
EPA estimated concentrations of stern tube packing gland effluent pollutants based on data for
the vessel types examined in the Report to Congress (Table 21). Contaminants identified in stern
tube packing gland effluent include metals and volatile/semivolatile organic chemicals
(sVOCs/VOCs).
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