I suppose the cold war mentality had something to do with the secrecy, but is there any practical reason to keep the search secret from the soviets? I can only think that it would give them a clue to where the subs were, but, so what?
Would it have been a security breach if the soviets had found the subs? What would the soviets have gained? BTW, I don't think I ever learned how much they found. Were hulls or portions of hulls found?
Details of U.S. submarine construction would be very valuable to anyone planning to fight U.S. submarines (find the vulnerable spot). More than this, the Soviets could easily have picked up quite a bit of technology they didn't have, giving them a serious advantage — especially since the U.S. did not have a clear picture of Soviet technical capabilities. And, of course, both subs were loaded down with nuclear warheads, & U.S. warheads were (still are) significantly better in terms of yield per unit mass & per unit volume. A part of the secrecy, though, was undoubtedly just "on general principles" paranoia.
To be frank, they're pretty vulnerable to any sort of attack - if you can find them in the first place. The most valuable information about a submarine is its sound and vibration signature and how it displaces the water. Information such as the size and shape of the propellor, design of the shaft, material covering the hull, size of engines, type of sound insulation would all be invaluable in this regard.
I like the Hughes Glomar Explorer story better. I remember my geology professor in college going on and on about the importance of mining undersea manganese nodules while the whole time it was all just a front for an attempt to find a Russian sub.
You must not have seen the recent re-make of the Andromeda Strain where the future us sent back a message via a worm hole saying that those vent and nodules contain the only antidote to this virus
This makes it sound as if finding TITANIC was just a "bonus" or something, not the case, Ballard truly wanted to find TITANIC and his love for it was genuine. I have read his book Discovery of the TITANIC 3 times and that passion is palpable in those pages.