There is no such theory. You can clearly see from construction pictures that those ships have displacement hulls. A displacement hull won't plane no matter how much power you put into the shafts.
Well it's more of a conspiracy theory really. Along with the Aurora aircraft, Area 51 aliens and the like. Just slightly more believable than the rest.
> A displacement hull won't plane no matter how much power you put into the shafts.
I wouldn't be so sure, the main difference between the two is that a planing hull has an angle of attack in regards to the water, so it can generate lift. You can achieve the same by increasing stern trim on a displacement hull.
As for it being flat on the bottom, there are also less stable flat planning hulls that work so that doesn't disqualify it either.
http://www.navweaps.com/index_tech/tech-028.php