The Living must have a vessel to cross the Sea of the Dead. Any craft intended for our waters will do, from a simple coracle, a flat-bottomed river boat, or a sailing ship. The trick is getting the vessel to the Dark Sea.
Some find wind to fill sails on the dark sea, but this wind is rare and fickle.
The easiest way to move a vessel across the dark sea is to hold a light aloft at the bow. The hands of the sea will slowly pass the craft from one to the other. Light may draw eyes from out of the darkness however.
Holding aloft the holy symbol of the god of the underworld will similarly move able craft through the sea, but it is said He will seek payment for this favor.