What Is Prop-Wash (Blower)?

Prop-Wash is a tool employed to remove large amounts of bottom sediment that is believed to be covering artifacts. The top part of a blower is a device that is placed over the propeller of a salvage vessel.

While the boat is completely stabilized by anchors, its engines are turned on creating a downward whirlpool action that is then directed to the ocean floor via large diameter tubes. This results in blowing away large amounts of sediment.

A prop-wash is effective only in fairly shallow water and its effect is greatly diminished beyond the distance exceeding 50 feet. The principle is as follows.

A prop -wash is a device that throws out a jet of water of higher pressure than that the surrounding water. Up to the size of the impellor the jet is smaller or larger. The pressure is directly a result of the size of the prop and the size of engine used to drive the prop.

The jet has a large pressure at the center and this pressure drops off at the edge until it finally is no more. That is why a prop-wash will dig a cone shaped hole in the sand. Deep in the center and shallow at the edges. The sand is deposited outside this high-pressure area. So there will be a large area where the sand is removed.

Although scuba-equipment can be used with all of the equipment it is not recommended.