	:: The Vikings of Bjornstad :: Viking Ship Museum Roskilde, Denmark - Spring, 2008
The text that follows is from a sign in the Viking Ship Museum in Roskilde. It is reproduced here for informational purposes, although it contains elements (e.g., catapults??) that raise issues about its accuracy. The museum's web site is here.

Weaponry

According to mid-11th century Norwegian law, the standard weaponry on a warship had to consist of 1 bow and 24 arrows per thwart and a shield, broad-axe, a sword and a spear per man. Neither helmet nor ring mail are mentioned in the law although leather helmets and leather armour could most probably be considered as "ordinary". The weaponry onboard the ships of the nobility was more valuable and sophisticated than that on smaller warships.

Probable weaponry on a 30-sessa like Skuldelev 2:

Offensive weaponry
34 bows, 48 arrows per bow
34 quivers
80 swords
60 light axes
30 battle axes
160 throwing spears
Catapults and ammunition

Defensive weaponry
20 coats of ring mail
20 metal helmets
60 leather sets of armor
60 leather helmets
80 large, round shields
40-80 reserve shields
Leg and lower arm guards

The bow
The Vikings introduced the bow and the axe to the weaponry of several countries, among others Ireland. As a fast and accurate weapon, the bow was terrifying. It was especially effective when many archers shot a continuous rain of arrows at the enemy. A skilled archer could have five to seven arrows in the air simultaneously.
The bow was in use as a weapon of war until as recently as the end of the 18th century. At the time, rapid fire with a bow was four times faster than with a musket. It could also shoot as accurately and over the same distance. What is more, the target was never obscured by gunpowder smoke.

2,246 bows
The ships sent against Roskilde from Norway had a total of 2,246 thwarts and consequently a "firepower" of 2,246 bows. All these bows were presumably not shot at the same time, but imagine the firepower of just one 30-sessa with men shooting arrows in series of five.