An anchor is a device that is used to stop a ship or boat from drifting away. Anchors are made from heavy metal, and are hooked so they catch onto the seabed. They are attached to the ship by a long chain or rope, and are let down when the ship needs to be still, and lifted up when the ship needs to move again.
A barge is a low boat with a flat bottom that was originally designed to move by being towed or pushed along. Barges were once propelled by pushing them along using a bargepole, or were pulled by a horse walking along the shore. Modern barges are propelled by motors.
A catamaran is a type of boat that has two hulls. The hulls are connected somehow, ranging from a simple connection with thin rods to the bulk of the boat forming the bridge.
Catamarans may be either sail or motor powered, and can be any size from tiny sailboats to quite large ships.