When operating in open sea areas, it was not practical to use small-scale hydrographic features tactically. Only harbors, bays, and shorelines were charted with sufficient accuracy to show features smaller than a km or so. Even inshore, the problem was knowing your own position precisely enough, especially when submerged. You could, and can, distinguish trends - head toward the river mouth, then turn seaward. And you could distinguish the 10- and 30-fathom curves and use them constructively. But you couldn't drop the sub into a "deep hole" to hide. Not only were you unlikely to know the existence of the hole (except in shallow water) but you were even less likely to know where your boat was in relation to the hole.
One difficulty was that a submerged sub moves so slowly. At 5 kt, pretty good submerged speed, the sub will cover 1 km in about 11 minutes. That's time for two depth change runs by a DD that has you located, more if there are more DDs. That doesn't give you a lot of opportunity to use hydrographic features for evasion. All you can do is use the bottom contours as shown on the nav chart, and try to make use of the trends. From what I have read, that was pretty much all they actually did, and you can do the same thing in the game.
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