But after that, you get to wander the fort. The fort itself is interesting. Part of the time you're outside, and you can go through an oddly shaped connecting tunnel. There's also an aquarium in the fort, which was so-so. Overall, I was happy with everything but the Greenpeace exhibit. I would have paid extra if that wasn't there - it obscured some of the features in the rooms in the fort.
Getting there. From the train station, catch the #34 bus, which takes you directly to the fort. The bus terminal is just outside the train station. Alas, the bus only runs once an hour, and if you miss it you might do what I did: walk north to the dike, and follow the dike west (and then south) to Fort Kijkduin. Along the way, you get a view of Texel Island, and of Fort Erfprins, which is surrounded by giant earthworks. It's clearly a modern, manned military base, so I didn't even try to go in.
Going further north, there were several other boats you could go on, including a light-boat (f2.50), which looks like a boat with a light house on it. Going up to the musuem, you see a HUGE submarine. This is the one connected to the museum. The Maritime Museum takes museum cards, so I went in and briefly strolled through the museum. All the descriptions were in Dutch, so I quickly passed on to the submarine. This one is much bigger than the Russian sub.
Still in the museum is a military vessel that you can walk around on. Although space seems tight on this ship, it's far roomier than the two submarines.
Getting there. The marina is on the north-east edge of Den Helder, a short walk from the train station, and right next to the Ferry terminal.