Free City of Tenriver
In ages past, the enigmatic blue giants known as the Arcane came forward and offered a seafaring tribe of elves an odd item: a large metal throne to be bolted onto a ship. The Arcane claimed it would allow them to make the ship fly. More than that, though, they claimed it would allow them to fly their ship through the heavens, from their own world to the other worlds in the night sky. The called it a helm, and they called using it to fly through the stars “spelljamming.”
A spelljamming helm is typically a chair that is bolted onto the ship it is to propel. They are quite sturdily built, and while they are not adorned with gems or rare metals, they look quite throne-like. They are typically well cushioned and comfortable. A standard helm is designed to fit any medium-size humanoid, and anything smaller can sit in it as well. The arcane build helms to suit other races, though, including up to huge size humanoids.