How do I sneak into a port if the water is so shallow?

[Tom]

Originally Posted by kasperl

the water is only about 10 meters deep, not even enough to let me dive to periscope depth.

How did you check the depth? By asking the navigator for depth under keel? If so, then there is enough water for diving. When you're on the surface, your keel is already at 5 meters or so. With 10 meters of water under the keel, that makes a total of 15 meters. Periscope depth puts your keel at 13 meters, leaving a safety margin of 2 meters.

As this wasn't historically done (except once, at Scapa Flow), I haven't done much harbor raiding, but the few times I did try it out of curiosity, I was always able to sneak in at periscope depth. Getting out proved to be the difficult part.