Main Question: How would a pirate ship that is able to submerge down to the deck work?

Additional information: The ship would ideally be made of wood, but it would be fine to make it out of metal. The idea behind this submersion is to dodge enemy cannon fire while still being able to fire on them. The ship already has a series of "harpoon cannons" inspired by Sea of Thieves that allow it to bank around enemy ships quickly. It also has ten cannons, two on each side below deck and three on each side above deck. The cannons are placed on tracks that have locking mechanisms to keep them from shifting. Any help or commentary on all aspects of the ship would also be appreciated.

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    $\begingroup$ "Submerge down to the deck work": Which means that it is standing still. What good is a pirate ship which cannot move? Do they hope that the officers on the prey ship are all drunk blind and will collide with them? (Remember that in the age of sail naval cannon were basically ineffective beyond a hundred meters or yards or so, both because they were woefully imprecise and because nobody had developed the theory and practice of calculating a firing solution at sea. Most engagements were fought at distances of a few tens of meters or yards, quite often even closer.) $\endgroup$
    – AlexP
    Jan 7 at 20:48
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    $\begingroup$ If it submerges "down to the deck" but it has cannons below the deck, it needs to seal its own gunports (really well!) or sink. Also, the sea has this tendency not to remain where you left it, but to have big waves. $\endgroup$
    – Cadence
    Jan 7 at 21:07
  • $\begingroup$ The closest thing I can think of is the USS Monitor which sat extremely low in the water (low freeboard) but that was a specialty steam-driven ship for use in coastal waters. It seems unlikely it would work for a wooden sail powered seagoing vessel though. When semi-submerged, hull drag rises considerably because all of the hull surface area in contact with water, the masts, sails, and rigging protrude up considerably and therefore remain vulnerable, and the heavier waves in the ocean run the risk of swamping the vessel, as Cadence points out. $\endgroup$ Jan 7 at 21:29
  • $\begingroup$ Could this work like a dry dock, submerging below the waves, then reemerging all around the prey? Being surrounded and out of the water may unnerve the preyed-upon crew. Keeping your powder dry and you men alive might pose some challenges, though... $\endgroup$
    – bukwyrm
    Jan 7 at 23:14

2 Answers 2


It would work just like like downtown - - - Melbourne

Let's take a look at the HMVS Cerberus. She's exactly what you're looking for! A wood/iron composite ironclad with heavy armour plating and the ability to non-terminally sink and pop back up again. Your pirates will just need to fit their ships with tanks and pumps sufficient to empty said tanks.

For added protection, Cerberus could take water into ballast tanks, decreasing her already low freeboard until only the turrets and breastwork were visible.

She was already so low in the water that they had to build up around the deck in order to make her capable of sailing upon the open ocean.


Submerging a ship does not pose a problem: it is the reverse process that may require some finesse.

I propose large tanks that can be blown out by adding, say, sodium into the water (they are pirates after all, they chose a life of danger), this might be done by pushing out sodium rods from oil filled vessels that are mounted in the tanks. After the ship has reemerged, the tanks are closed to the water, and very gingerly vented.

  • $\begingroup$ I like the idea (+1), but I think you can elaborate on the sodium part. IIRC sodium + water = explosion + fire? $\endgroup$ Jan 8 at 2:41

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