Bubble System Designed to Push Bow Wave

bow wave

By The Maritime Executive 2017-11-06 01:35:39

Inventor Chris Kinman has designed a bubble system that he claims can reduce fuel consumption on large cargo ships by 35 percent, at the same time boosting speed by 30 percent. Unlike hull lubrication systems already developed, Kinman's system focuses on the bow of the ship.

“A ship spends a lot of energy making a bow wave and then trying to climb it,” says Kinman. “And then spends even more energy pushing its own weight of seawater aside every minute of a voyage to make way for the hull.”

On a very large, fully loaded ship traveling at 16 knots, the mass of water pushed aside every 60 seconds is something in the order of 200,000 tons, he says, calculated as displacement loaded multiplied by the number of hull lengths traversed in 60 seconds. 

“It is not difficult to see that a lot of power produced by the propulsion engines is used to push seawater aside to make way for the ship. This happens over and over, every 60 seconds for the entire duration of a ships voyage. A lot of fuel is wasted pushing some eight billion tons of seawater aside over a 31 day voyage.”

While a bulbous bow neutralizes the “hill climb” effect, the ship must still push huge masses of seawater to each side.

Kinman's system involves the installation of a semi-guided bubble system comprised of a stack of horizontal plates, like a deck of playing cards, arranged with spaces between them. These spaces form a stack of open sided ducts which guide bubbles horizontally and push water along in the same direction.  
The forward movement of the ship puts pressure on the bubble front, confining it within the ducts. The bubbles blown out of tubes expand three times in volume as they rise to the surface and continually and increasingly push seawater to the sides as they rise, instead of the ship doing it. 

The air is pushed towards the stern where it accelerates the flow of seawater in a laminar flow which is exhausted at the trailing end. Like a jet engine, this contributing to propulsion effort. The spent bubbles cloak as much as 60 percent of the side of the hull.

“This is not about bubble lubrication,” says Kinman. “The primary objective is to reduce the density of seawater that lies ahead of the ship by foaming the sea with a bubble field. This provides a low density hole ahead of the ship which it glides into with reduced propulsion effort. A lot of used bubbles also cloak the sides of the ship and provide collateral bubble lubrication, which is a secondary benefit.”