Ships and Submarines: The Viking Longship

Understanding Ships and Submarines: The Viking Longship

A longship hull worked because water pressure increased with depth. The lower parts of the hull experienced more pressure than the upper parts. This difference created an upward push.

As crew, cargo, weapons, and supplies were loaded, the vessel sank farther until it displaced enough water to support the added weight. This gave crews a practical limit.

Loading too much made the ship sit lower, reduced its clearance above waves, and made water more likely to enter. A longship could carry useful loads, but its best speed and safety depended on not overloading it.

Its narrow form helped it move efficiently, though it came with a tradeoff. A narrow hull has less area pushing through water, so it produces less drag at many speeds. It can be quick under oars because each stroke helps drive a relatively light vessel forward.

Yet a narrow boat can roll more easily than a wide one. Viking crews managed this through skill, careful loading, and the shape of the hull. Heavy items were kept low.

People had to shift their weight carefully. In rough seas, the flexible wooden structure could bend slightly with waves instead of resisting every movement like a rigid box.

The sail turned wind energy into forward motion, but it did not work like a modern triangular sail. A square sail was especially effective when the wind came from behind or from an angle behind the ship. The crew could adjust the sail and use a steering oar at the stern to hold a chosen course.

Sailing directly into the wind was difficult, so crews often changed direction, waited for better weather, or used oars. Rowing gave reliable control in narrow channels, near coasts, and during landings.

It required food, rest, timing, and teamwork. A ship could only maintain rowing speed while its crew had enough energy.

Longships show that seaworthiness is more than simply staying afloat. A seaworthy vessel must remain controllable when waves, wind, cargo weight, and crew movement all change. The overlapping planks in clinker construction spread forces across the hull.

Iron rivets and wooden parts held the planks together while allowing some movement. This made repairs possible with available materials, an important advantage far from home. Students studying this ship should pay attention to tradeoffs.

A feature that improves speed may reduce stability. A shallow hull improves access to rivers but can limit cargo space. Good engineering is often about balancing competing needs for a particular journey.