The boats range from a couple of metres long and fitted with complex miniature steam engines, to dinky little numbers propelled by nothing more than an enthusiastic child. There are even xray scans of the interior of many of the boats so you can see the ingenious propulsion systems used.
My personal favourite was the mechanical dolphin which spouts water.
Unfortunately you can't see any of the boats in action, but they do have a video of a number they brought back to life. That they still work after so many years is a testament to the craftsmanship of the artisans who created these little aquatic masterpieces.
While you are at the Maritime Museum make sure you also tour the Submarine and talk to the guides who served in the navy. It's fascinating to hear about life under the ocean from those who lived it.