Power Design Features of Viking Warships
The oars were made in one piece mainly from spruce which gave them their properties of flexibility along with lightness. Oars were designed in various lengths being between 15 and 25 feet long. The handles were carved into round or square section with the flat blades curving upwards at the tips. Most oar designs incorporated a leather strip wound around the oar handle where it was located into the rowlock.
The rowers sat on wooden boxes that held their clothes, swords, armor, and personal possessions, and from here they rowed with perfect synchronization.
There were several designs of rowlocks. In one design the rowlocks were carved out of the fork joint of a tree branch, with the fork providing a backstop for the oar. A rope, which passed through a hole made in the rowlock, was tied around the oar keeping it tight against the backstop.
Another design, utilized mainly on Viking warships, used iron hooks fastened to the gunwales, with the oars being lashed onto the hooks by ropes.
The most popular rowlock design appears to have been one where holes were made into the longship's hull below the gunwale. The strake board that the holes were made in was designed to be stronger than a normal strake as it had to withstand the torque and thrust produced by the lever action of the oars against the sea. The oar holes had a slot cut into them to allow the wide blade to pass through. The apertures could be lined around the inside with leather acting as a bearing which reduced friction against the leather protective strip around the oar. When the oars were stowed in port, or when rough seas were encountered and the oars withdrawn, the oar holes could be covered over with circular wooden discs.
Sail and Mast Design
The single sail was designed to add to the longships propulsion and was located amidships on a single mast. The mast was held securely in position by a block of oak fixed to the bottom of the hull between two stems and supported by various wooden slats.
The sail was made from spun wool, being up to 40' across and could be lowered and raised as required; a later design used a wooden spar attached to the bottom edge of the sail to facilitate sailing close to the wind.
The longboat was steered by a large rudder situated aft on the starboard side of the hull. Its design resembled an elongated broomstick, starting off at the top in a round section handle, flaring from about from about the middle section ending in a flat fan-tail blade.
The rudder appears to be the only chink in the longships design as it seems to be a bit over designed, having numerous ropes, slings, supports, and levers, as well as being mounted on the aft starboard side of the hull. However the captain was able to maneuver the ship using the rowers or the sail along with the rudder.