INTRODUCTION
More than half the tonnage handled in the military is petroleum. To do your job as a supervisor, you must
know the responsibilities and procedures for loading and unloading petroleum tankers and barges.
PART A - TANKERS
The Military Sealift Command-controlled tanker fleet provides worldwide transportation for the delivery of
petroleum products from refineries to Department of Defense (DOD) storage facilities. The tanker fleet
consists of approximately 30 tankers, which vary in size from 27,000 to 38,000 tons. The various types of
lease contracts are as follows:
Bareboat Charter - The tanker is leased to MSC, and MSC personnel crew the ship and are responsible
for all expenses.
Time Charter - From a few weeks to a number of years, the owner provides the crew and pays all
expenses.
Single Voyage Charter - The ship is leased for a single voyage, and the owner is responsible for the
crew and all expenses.
Dirty Service - For heating oils and crude service.
Clean Service - For finished products only. Ships cannot carry split cargoes without prior approval from
the Defense Energy Support Center (DESC).
When referring to various locations on a ship, or when describing certain conditions of the ship, the following
terms are used:
Bow - Front end of vessel
Stern - Rear end of the vessel, also called the "aft section"
Midships - Center of the vessel
Port - The left side of the ship when standing midships and facing the bow.
Starboard - The right side of the ship when standing midships and facing the bow.
Bunkering - The fuel that is used to power the ship.
Gross Tonnage - The total internal cubic capacity of a vessel less exempted spaces, such as tanks for
ballast water. This weight is expressed in units of 100 cubic feet per ton.
Net Tonnage - The registered tonnage of a ship after deductions have been made from the gross
tonnage. Examples of deductions are crew and navigation spaces.
Light Displacement - The weight of the vessel. This does not include the weight of cargo, passengers,
fuel, water, stores, and other items that are needed on a voyage.
Loaded Displacement - The total weight of the vessel. This includes the weight of cargo, passengers,
fuel, water, stores, and other items that are needed on a voyage.
Deadweight Tonnage - The carrying capacity of a vessel in long tons (2,240 pounds). It is the
difference between light and loaded displacement.
PART B - BARGES, PUMPS, TANKS, AND MANIFOLDS
Barges.
Self-propelled. These barges move under their own power and are used in inland and coastal
waterways. They must maintain a crew at all times.
Non-self-propelled. They must be moved by tugboats and can be used for temporary storage. They are
equipped with their own pumping systems.
Pumps. Most tankers have two pumping systems.
Centrifugal pumps for off loading the cargo.
Gear or piston pumps for stripping the cargo tanks dry.
Ship's Tanks and Manifolds. Most tankers have the capability to carry up to five different products.
Ships' tanks are arranged abreast and numbered from bow to stern.
5-2
QM 5098
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