Not sure I understand the question... Wasserstahl is not listed as special equipment on any of the ships (that I'm aware of). In fact, it's only mentioned once in the rulebook: "Late in 1901, Graf Ferdinand von Zeppelin unveiled his latest rigid airship design, encased not in cloth or aluminum, but Wasserstahl. The manufacturing process of 'hydro-steel', as it came to be known in the English speaking world, was a jealously guarded secret, one which the other Powers had great difficulty in penetrating."

On the ship builder v 2.0 it lists a Wasserstahl Hull .

"The Wasserstahl hull option has not been included in any print source yet... it's a placeholder for future expansion."
To quote Dan from years past.   Perhaps an expansion that never came to be.
Could it be that this became "Soviet Armor"?

I know that I started to put Wasserstahl in my Iron Shipyard and then changed it to Soviet Armor sometime before I posted it.

Paul