TABLE 2-1 Typical Vessel Types, Ballast Needs, and Pumping Rates

Ballast Needsa

Vessel Types

Typical Pumping Rates (m3/h)

Ballast replaces cargo

Dry bulk carriers

5,000–10,000

Ballast required in large quantities, primarily for return voyage.

Ore carriers

10,000

 

Tankers

5,000–20,000

 

Liquefied-gas carriers

5,000–10,000

 

Oil bulk ore carriers

10,000–15,000

Ballast for vessel control

Container ships

1,000–2,000

Ballast required in almost all loading conditions to control stability, trim, and heel.

Ferries

200–500

 

General cargo vessels

1,000–2,000

 

Passenger vessels

200–500

 

Roll-on, roll-off vessels

1,000–2,000

 

Fishing vessels

50

 

Fish factory vessels

500

 

Military vessels

50–100

Ballast for loading and unloading operations

Float-on, float-off vessels

10,000–15,000

Ballast taken on locally in large volumes and discharged in same location.

Heavy lift vessels

5,000

 

Military amphibious assault vessels

5,000

 

Barge-carrying cargo vessels

1,000–2,000

a The three categories of ballast needs are not mutually exclusive. For example, a vessel in which ballast replaces cargo may also require ballast to control stability.

displacement, ship owners tend to use as little ballast as is necessary for the ship's safe, efficient passage when operating either with ballast or in ballast.

SAFETY

Ballast water is taken on board vessels to achieve the required safe operating conditions during a specific voyage or portion of a voyage. Proper ballasting (in terms of the amount of water taken aboard and its distribution) fulfills the following functions:

  • reduces stresses on the hull of the ship

  • provides for transverse stability

  • aids propulsion by controlling the submergence of the propeller

  • aids maneuverability by submerging the rudder and reducing the amount of exposed hull surface (freeboard or windage)

  • compensates for weight lost from fuel and water consumption

Ballast condition, including when and how much water is loaded, is determined by ships' officers, based on the specific vessel's operating needs and the



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