stikpusher
The “disruptive” & “dazzle” schemes were more effective against optical rangefinders and other such devices such as submarine periscopes. The overall dark schemes were more effective against aircraft. There is one of the new LCS ships in a camo pattern.
A couple of points of clarification/correction. Disruptive schemes were used in the US Navy until 1945 as German and Japanese submarines were considered more of a threat (it was harder to guard against them than aircraft that could be picked up on radar) until the Kamikaze was used starting in late 1944.
"The overall dark scheme" were more effective against aircraft" while technically true in many cases is missing a bunch of information. The most effective scheme for hiding a ship is one that matches the background. If the plane is high and looking down on the ship and the ocean, a dark tone is going to best hide the ship.
If, however, the attacker is low and searching against a light sky, a dark paint is going to stand out. The US Navy stopped using black paint on the masts of ships and as shadows in the hull numbers in the late 1980s/early 1990s because optically-guided surface skimming cruise missiles were able to use the high contrast of that paint to target the ship.
stikpusher
I was looking at photos of current USN Special Warfare Craft, to get an idea of the green camos worn today by some for their riverine ops. Interestingly, some also wear gray camo schemes of a similar type as seen on that particular LCS. I do not think that it is a ”one off” for covering exhaust stains. If so, why also apply a lighter color that is more likely to show any stains?
It's technically a "two-off" scheme as two of the LCSs are painted in a dazzle scheme. And yes, it is primarily to hide the soot stains from the diesel generators aboard - while both ships have different patterns, you can see that the black sections are in nearly the same location on both and extend aft from the exhaust ports. LCS-1 Freedom's captain sold it as a maintenance and crew moral effort and during an interview stated that he and the ship's XO looked at some old photos of ships or design sheets for inspiration when they laid it out. If you look at them, they do a bad job at breaking up the ships' outlines or obfuscating direction and speed.
As far as the colors being green and/or gray, the Navy learned in WWII that it wasn't the color that mattered in camouflage as much as *tone*. If you think about how many modelers discuss "Scale effect" and how the colors mute out with distance, this is essentially the same thing. Close up, color can matter, but as you put more air and moisture between a subject and the viewer, the vibrancy fades and you merely need to match against a light sky or a dark ocean. Gray can also be good at taking on hues from surrounding sources and can adapt somewhat.