Wondrous item, very rare
This black-lacquered navigational device, chased with silver, can be used to plot a course for a ship through the benighted seas of Shadowfell. A ship equipped with the shadow sextant allows the ship to move 50 miles an hour while on the shadowy seas and then reappear in a location on Material Plane (or another connected plane) effectively moving more rapidly between points. A shadow sextant can be used only at night, and charting the ship’s course takes 1 hour. Once preparations are complete, you must make a DC 20 Intelligence (Arcana) skill check to shift a vessel into the Shadowfell. The DC increases by 5 each time the ship size increases above that of a caravel (for example, the DC for a carrack would be 25, and a galleon would be 30).
If the check fails, no course can be found and the shadow sextant cannot function until the next dusk.
If the check succeeds, the ship and all creatures on it slip into the Shadowfell and can travel through it to other planes or to other locations on the Material Plane. Creatures unwilling to travel into the Shadowfell can elect to remain behind if they succeed on a DC 20 Wisdom saving throw, though if the ship departs they may be stranded at sea. The ship can remain in the Shadowfell until the sun rises in its equivalent location on the Material Plane or for a maximum of 12 hours in any case. After a shadow sextant has been used, a DC 30 Intelligence (Arcana) skill check is required to activate it if at least one night has not passed between uses.
Pirate Campaign Compendium © 2018, Legendary Games; Lead Designer Jason Nelson. Authors: Alex Augunas, Jeff Gomez, Matt Goodall, Jim Groves, Tim Hitchcock, Victoria Jaczko, Jonathan H. Keith, Lyz Liddell, Thomas J. Phillips, Alistair J. Rigg, Alex Riggs, Loren Sieg, Neil Spicer, Todd Stewart, Rachel Ventura, Michael D. Welham, Linda Zayas-Palmer.