Ships Ballast

1
Ships Ballast

• Why the zebra mussel is in Minnesota

2
The Need for Ballast

• Ballast is used in boats to provide stability
• Ballast can be people, weights in the bottom of
  the boat and keels.

3
Human ballast

• The people on their sailboats provide ballast to
  prevent their sailboat from tipping over.
• The farther out they can hang the faster the
  sailboat can go without tipping over.

4
Cargo Ships

• On cargo vessels water ballast is added to tanks
  in the ship.
• This helps the ship travel at the proper depth.
• This improves propeller immersion, steering and
  helps to control trim and draft.

5
Ballast Tanks

• The tanks are located near the bottom of the
  ship.
• Because water is not very heavy a large ship may
  need to pump in a large amount of water to be
  stable

6
Without Ballast a ship can be in trouble

• This ships ballast tank and pump malfunctioned.
• Too much water was pumped out of a nearly empty
  ship in fresh water.

7
How it works
8
A Ship discharging ballast in Duluth
9
All kinds of organisms can stay alive in ballast
water and be discharged in a new place.
10
The Caspian shrimp is one of over 20 foreign
species that have thrived in Lake Superior.
11
Eurasian Ruffe - first discovered in 1980. Tends
to crowd out more desirable fish species.
12
Efforts are being made to inspect and sterilize
the ballast water.
13
In the Ballast free ship water is constantly
streaming through the ship, so no invader can
make it to the destination port.