Seven Days At Sea: Smugglers' Oars, A System-Agnostic Magic Item

Smugglers' Oars

Description:  One or more pairs on oars suitable for use on a ship's boat, made of a smooth, dark wood of unknown origin.  They are strangely difficult to look directly at and always feel cool to the touch, even under a blazing tropical sun.  Mystical senses reveals a subtle aura of deceptive magic.  More advanced auguries reveal a strong bond between the oars in a given set (which could be as many as twelve, although a single pair is most common) which could be used to trace the location of any that are missing.

Powers:  When an appropriate number of Smugglers' Oars are used to row a small watercraft of any kind, the boat, its contents and crew are undetectable to outside observers.  It leaves no wake and causes no disturbance in the water, counts as invisible and inaudible, and even water-dwelling creatures that might track by scent or sound cannot perceive them.  Creatures that are directly affected by the boat or its crew (for ex, in the case of a collision, attacks, or spellcasting) are exempt from this stealth effect for ten combat rounds afterward, although any initial attacks would be treated as coming from an invisible enemy.  The boat takes 1d6 rounds to become invisible after rowing starts, and the effect lasts only as long as rowing continues.

This magic only functions if the boat is being rowed entirely by a single set of Smugglers' Oars, with small rowboats needing only a single pair while the largest launches or longboats might require as many as a dozen oars.  When found randomly, 75% of the time a set of two oars will be encountered.  The remainder of the time, a set of 1d6 pairs of oars (so 2-12 total) will be found.  GMs may wish to complicate things further by having some oars from a larger set missing, which will require effort to track down.  A larger set can be "broken down" to row multiple smaller craft, but sets cannot be combined to row a larger craft. 

Possible Origins:  Smugglers' Oars are generally crafted on commission from scoundrels, spies, assassins and (unsurprisingly) smugglers.  The magic required is relatively straightforward, but the rare extraplanar wood required to make even a single pair of oars is very expensive.  Enchanting larger sets to equip bigger craft is prohibitively costly, although these costs can be ameliorated by questing to acquire the ingredients for the project.   

Complications:  The primary danger in using Smugglers' Oars is the risk of collision with other water traffic due to being unseen and unheard.  This is rarely an issue when (say) landing illegal cargo on a lonely seashore, but presents difficulties in a busy harbor or canal network.  The sudden appearance or disappearance of a boatload of people and cargo in front of witnesses is also likely to evoke comment.  Many customs agents and naval crew are familiar with the existence of Smugglers' Oars and will treat anyone owning them as criminals by default.  

Design Commentary:  Light sources carried by the boat will be invisible to outside observers as long as the stealth effect is operating.  This not only helps with landings during the dark of the moon, it offers possibilities for exploring the waters of the Underdark in relative safety.