The Sundered Sea - A 5th edition Dungeons & Dragons campaign
Aside from thaumium, the arcane engine is one of the most significant cornerstones of trade, exploration, and commerce. The system generally consists of a main engine which is linked to two or three long, thaumium-infused rails running along the keel and waterline of a ship’s hull. When powered with refined thaumium, the rails are energized – inducing a gentle, forward-driving current around the ship, and also seemingly mitigating whatever energies conspire throughout the Trackless Seas to send ships adrift, never to be seen again.
Construction and design
The principles and basic functioning of the arcane engine is largely reverse engineered from existing contraptions and thaumaturgical machines scattered throughout the city of Sunderhold, but have seen marked improvements and refinements through the combined efforts of scholars, dwarven smiths, and even gnomish tinkerers over the past hundred years.
Because of the extreme difficulty in sourcing materials, the artistry and skill in forging and assembling them, and the maintenance and upkeep in keeping them functioning, arcane engines are highly prized pieces of equipment and often as valuable (if not more so) than the ships they are fitted to. No arcane engine and corresponding drive rails are alike – most likely due to the fact that designs are constantly being refined, and each system is often designed around the particular ship to which the engine will be fitted.
The methods of production and maintenance of these engines are prized trade secrets, and there are currently only three shipwrights in the city of Sunderhold who is able to produce and service these machines. Across the Trackless Sea in the settlement of Runner’s Rest, only one shipwright is available to work with the complicated thaumium engineering.
Operation and function
Again, while designs from engine to engine often vary, the basic operation of an arcane engine involves placing refined thaumium into the “burner” of the engine, which is typically located in it’s own chamber near a ship’s stern. Long, thaumium-infused rails branch out from the engine to the outside of the ship’s hull, typically running along the keel and/or waterlines.
When powered, the rails tend to produce a faint, greenish glow which radiates around the ship. A gentle but steady current is induced in the water immediately surrounding the ship, generally driving the vessel forward at a speed of approximately 2.5 knots, or 3 miles per hour. This forward speed is valuable when there is no wind to drive the sails, or can be used in conjunction with the standard array of mast and sails present on the ship. Additionally, a powered arcane engine exhibits a little-understood but invaluable protective aura commonly referred to as “the Thaumium Veil.”
The Thaumium Veil
Deeprunners making the treacherous journey between Ur’duryn and the Waning Isle make their journeys in constant fear of the Trackless Sea’s bizarre and dangerous properties. In the roughly eighty years since the founding of the Deeprunner’s Alliance, more than twenty-five ships have vanished – sometimes entirely, or often the missing ships would be encountered years later by other runners, dilapidated and vacant.
The only consistent link found in the ships that have succumbed to the forces of the Trackless Sea is that recovered captain’s logs always show the arcane engines of the ship were disabled before the entries stop – either because they lacked the thaumium to power the engine, or they were trying to conserve their reserve.
Researchers and scholars cannot determine how the arcane engines prevent the forces of the Trackless Sea from claiming ships, but Deeprunners don’t particularly care so long as their journeys back and forth to Sunderhold are successful. As a result, the protective effect of an energized arcane engine is commonly referred to among Deeprunners as the “Thaumium Veil.”