ships ballast why the zebra mussel is in minnesota

Ships BallastShips Ballast

Why the zebra mussel is in MinnesotaWhy the zebra mussel is in Minnesota

The Need for BallastThe Need for Ballast

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

keels.

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

keels.

Human ballastHuman 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.

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.

Cargo ShipsCargo 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.

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.

Ballast TanksBallast 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

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

Without Ballast a ship can be in troubleWithout 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.

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

ship in fresh water.

How it worksHow it works

A Ship discharging ballast in Duluth

A Ship discharging ballast in Duluth

All kinds of organisms can stay alive in ballast water and be discharged in a new place.

All kinds of organisms can stay alive in ballast water and be discharged in a new place.

The Caspian shrimp is one of over 20 foreign species that have thrived in Lake Superior.

The Caspian shrimp is one of over 20 foreign species that have thrived in Lake Superior.

Eurasian Ruffe - first discovered in 1980. Tends to crowd out more desirable fish species.

Eurasian Ruffe - first discovered in 1980. Tends to crowd out more desirable fish species.

Efforts are being made to inspect and sterilize the ballast water.

Efforts are being made to inspect and sterilize the ballast water.

In the Ballast free ship water is constantly streaming through the ship, so no invader can make it to the

destination port.

In the Ballast free ship water is constantly streaming through the ship, so no invader can make it to the

destination port.