Vikings loved to brawl, with both their enemies and with each other. Viking sagas are filled with tales of even longstanding friends happy to settle disagreements with steel. But as they piled onto their longships to go pillaging, their boarding process was a good deal more civilized than the melee that is modern air travel. For one thing, their storage was one-to-one; when 30 Vikings got onto a ship, there were 30 places to store things.
That's because they carried their seating on board with them, and their seating doubled as their storage. Prior to boarding, the decks of a ship were bare. Each Viking plunked his chest down at his own rowing position.
Enough Viking chests have been found, and replicas made, that we can take a look at their design. It's both intelligent and purposeful. The first thing you notice is that the tops were rounded to shed water, and perhaps to provide a modicum of comfort.
The sides double as the legs, and they're angled to provide stability on the deck of a rolling ship. And unlike a typical storage chest, the bottom is raised several inches off of the ground to keep the contents dry as the ship takes on water in high seas.