I used to know this fellow that was on subs from the 60's through the 90's. He hinted that there was some sort of lubricating system that would exude a substance that would dramatically enhance a sub's ability to slip through the water on an emergency basis. I wonder if y'all had heard of it, and if it had ever been used on a surface vessel.
The Navy experimented with double hulled ships in the late 1970's and early '80's; the space between the hulls was hollow and high-pressure air was pumped into the space. Small holes in the outer hull would allow bubbles to escape and flow around the hull, thus "lubricating" the hull/water interface and reducing friction. This had a two-fold effect - increasing speed and/or reducing fuel consumption.
The big drawback was increased hull noise as the bubbles surfaced and the compressor noise was detectable.
