First Mentioned: WB2014 Duke Forecastle - Part 3
Beam weapons are the standard weapon of a ship. They are stored in the masts and fire a form of Shockmancy. Their damage output is calculated by some number summed up from every crew member and divided by another number related to the ship's quality and condition. Seafarers give a decently sized boost, while a theoretical landlubber crewmember would only give a tiny one.
Beam weapons cannot penetrate the water's surface, and they are thus useless against submarine units.