Helm of the Scavenger

From Waterdeep: Dungeon of the Mad Mage, page 297.

Description
Wondrous item, legendary (requires attunement by a spellcaster).

This ornate chair is designed to propel and maneuver a ship through space.

Passive Properties. The following properties of the helm come into play even when no creature is attuned to it:
 * When placed aboard a vessel weighing between 1 and 100 tons, the helm generates an envelope of fresh air around the ship while it is in the void of space (but not underwater). This envelope extends out from the edges of the hull in all directions for a distance equal in length to the vessel's beam, so that creatures aboard and near the ship can breathe normally in space. The temperature within the air envelope is 70 degrees Fahrenheit.
 * When placed aboard a vessel weighing between 1 and 100 tons, the helm generates an artificial gravity field while the ship is in the void of space, so that creatures can walk on the ship's decks as they normally would. Creatures and objects that fall overboard bob in a gravity plane that extends out from the main deck for a distance equal in length to the vessel's beam.

Active Properties. The sensation of being attuned to the helm is akin to being immersed in warm water. While attuned to the helm, you gain the following abilities while you sit in it:
 * You can use the helm to propel the vessel across or through water and other liquids at a maximum speed in miles per hour equal to your highest-level unexpended spell slot.
 * You can use the helm to propel the vessel through air or space at a maximum speed in miles per hour equal to your highest-level unexpended spell slot x 10.
 * Provided you have at least one unexpended spell slot, you can steer the vessel, albeit in a somewhat clumsy fashion, in much the same way that oars or a rudder can maneuver a seafaring ship.
 * Whenever you like, you can see what's happening on and around the vessel as though you were standing in a location of your choice aboard it.

Drawback. While attuned to the helm, you cannot expend your own spell slots.