“One evening the spies of Önund saw Knut sailing not far off. Önund let a war blast be blown. His men took down their tents, armed themselves, and rowed out of the harbour (at the mouth of the river) and eastwards along the coast; they laid their ships side by side and tied them together, and made ready for battle. Önund sent spies ashore to tell Olaf, who had the dam broken and let the river into its bed. He then went down to his ships in the night. When Knut came off the harbour, he saw the host of the kings ready for battle. It seemed to him it would be too late in the day to begin a battle, as the whole of his host was not ready. His fleet needed much space for sailing, and there was a long way between his foremost and hindmost ship, and the outermost and the one next to the land. There was little wind. When he saw the Swedes and Northmen had left the harbour, he went in with such ships as could get room there, but the greater part of his host lay out on the sea (outside the harbour). Next morning, when it was almost day, many of their men were on land, some talking, others at their games. They suspected nothing until the water rushed down upon them like a torrent; large timbers followed, and were driven against their ships; these were damaged, and the water flowed all over the fields; the men on land, and also many of those on the ships, lost their lives. All who could, cut their anchor-ropes, and the ships drifted in great disorder. The large dragon, on which the king was, floated out with the current; it was not easy to move it with oars, and it drifted out to the fleet of the kings. When they recognized it, they at once surrounded it. As the ship had sides as high as the walls of a burgh, and many chosen and well-armed men were on board, it was not easy to capture it. After a short time Ulf jarl came up with his ships, and the battle began. Thereupon the host of Knut gathered from all sides. Then Olaf and Önund saw that they had gained as much advantage as was then possible; they pulled back and got loose from the host of Knut, and separated the fleets. Because this attack had not been as Knut had ordered, he did not row after them; they began to array the ships and make themselves ready. When they had separated, and each fleet was mustered, the kings counted their men, and found that they had not lost many; they saw also that the odds would be so great if they waited till Knut had made ready all his great host, and attacked them, that there was little hope of victory. They decided to row with all their ships eastward along the coast” (St. Olaf, c. 106).[[157]]

Before the conflict the sides of the ships were strengthened by viggyrdil (war-girdle) or vigfleki (war-hurdle).

“King Sverri was at Bergen (Björgyn) with his host, and all his ships lay ready and war-girdled at the gangways” (Sverri’s Saga, c. 52).

When King Svein of Denmark was pursuing King Harald with an overwhelming force,

“He (Harald) bid the men lighten his (ship) by throwing overboard malt, wheat, and pork, and to cut holes in the ale-barrels: this helped awhile. Then he had viggyrdils, vats, and empty barrels, as well as the prisoners of war, thrown into the sea” (Harald Hardradi’s Saga, c. 35).

“We will carry out on the boards (i.e. the sides of the ship) vigfleki, and defend ourselves as best we can, but not attack them” (Flateyjarbok).

A man with his shields protected the rowers from the missiles of the enemy; but in spite of this, many were often killed. Three men were generally stationed in each half-room, one for rowing, one for protecting the rower, and one for fighting.

Erling Skakki said to King Ingi: “If we now attack them and row against the current, and have three men in every half-room, then one must row, the other protect him, and we shall then have not more than one-third of our host in the fight” (Hakon Herdibreid’s Saga, c. 6).

“When the men on board the jarl’s ships began to fall and get wounded, and the line of men on their gunwales got thin, King Olaf’s men went on board. Their standard was carried on board the ship next to the jarl’s, and followed by the king himself” (St. Olaf’s Saga, ch. 48).

Stones were extensively used in sea fights.