The Northmen, finding their efforts unavailing, then turned their attention to trying to tow the ships below to the banks.
In some cases they were successful.

A few of the vessels also at the lower end of the mass succeeded in getting up their sails and drawing out from their fellows, for the wind was blowing down stream.

This, however, proved the destruction of the rest of the ships, for the great towers rising amid the lofty pillars of flames acted as sails and bore the fire-ships down upon the helpless crowd of vessels.
Soon they reached those nearest to them, and the flames, borne forward by the wind, sprang from vessel to vessel.

There was no longer any hope of saving a single ship; and the crews, climbing hastily across from one to the other till they reached those nearest to the shore, leaped overboard.

Although now more than half a mile below the city the flames lit up the walls with a bright glare, and the shouts of the exulting Franks rose loud and continuous.
The sudden shouting which had broken out among the Danes had alarmed the watchmen, who, ignorant of the cause, called the citizens to arms, and these on reaching the walls had stood astonished at the spectacle.
The flames were already rising from the three groups of ships which they had regarded with so much anxiety on the previous evening, and by the light they could see the river below covered with a mass of drifting vessels.