In the seemingly endless war between the De Madden Company and the Kraken States, the scientists of the Company ceaselessly work on new ways to defeat the fearsome Krakens and the human navies that most of them command. The latest ship they have come up with is the galley Maelstrom, the pride and joy of the Company fleet. At thirty feet in height plus a further five feet below the waterline, and three hundred feet long from bow to stern, the Maelstrom is low enough in the water to bring her guns to bear at short range.
Experiments were made with the oars to see how fast the ship could go. First they brought in slaves, convicted criminals and prisoners of war, but they would only row fast when whipped and could not do so for very long. Then they brought in well-paid and patriotic free men who were happy to row for their country. The ship increased in speed for longer, but only up to a point as even the most willing rowers were only human and would sooner or later tire.
So it was decided to experiment with the new sciences of clockwork, thaumatech and steam, and three methods of propulsion were developed. The first was a short term clockwork engine that when wound up (which took several hours even with the strongest of men and soft leather on the handles to protect the hands) that could row the oars for fifteen minutes-long enough to stoke up the boilers and have the oars rowed by a complicated system of piping, which was the second system. The third was a short term spell that again, could last only fifteen minutes as to make it last longer would cost too much in amethyst, so even if the pipes were broken and there was no time to wind up the clockwork engine, would hopefully last long enough to get the ship out of danger, or if that was clearly impossible, to launch a last attack.
Runes in silver were placed on the deck, sides and hull. The ones on the deck and sides acted as force-fields against purely magical attacks, although they could not protect against solid attacks as that would both block the oars from working and make it hard to walk around the decks. The runes on the hull made the copper bottom that protected against woodworm as tough as iron.
All along the sides were placed weapons meant to tear sails, bring down masts and decimate an opposing ships crew, or cause great bodily harm to Krakens. There were steam cannons, slow to load and somewhat hard to aim, but capable of firing either cannonballs or deadly grapeshot. The first could snap a mainmast with a direct hit; the second could kill anybody in close range by ripping their bodies apart. There were lighter lightning-guns, a larger and deadlier version of the C-47 thaumatech rifle. Whilst they could not do anywhere near as much damage, they were quicker to load with balls of amethyst and could fire for three minutes continuously.
There were other steam-cannons that fired barbed harpoons tipped with explosive, grappling irons for boarding larger ships, and fireballs for setting fire to other ships.
All of the cannons had mantlets, wooden shields with eyeslits for the gunners to see where to aim, capable of protecting the crew from arrows, shrapnel and weak magical spells. At the front of the vessel just below the bridge, so as not to block vision, were two huge steam cannons. Although it took quite a while to load them, once fired tests proved that at close range, they could hole a ship below to waterline or smash through an unarmoured deck of even a large vessel.
All this extra weight made the wooden oars break in testing, so they were replaced with oars of Dracorex Steel. The crew consisted of two Sea Wizards, half a dozen technicians to fix any small glitches, twenty sailors to raise and lower the mainsail and the anchors, and two companies of heavily armed and well trained Company Marines who had served several years in the Marines with good conduct records, as well as the Captain and his officers.
Heave Ho, Me Hearties
The PCs are either members of the crew, or have been press-ganged to serve on the vessel after a recent battle or a bout of disease killed some of the crew members.
Working for the Kraken States, the PCs must sneak into the harbour, past the guards, and plant high-explosive mines below the waterline.
Sink the Maelstrom
The PCs are in charge of a squadron of ships sent by Big Red to find and sink the Maelstrom before it can attack his home island and him personally.
I thank Scrasamax for giving me the idea with his Captain Blight submission from 30 Villains and Fiends.