structural:summarization
English navy

Alfred also tried his hand at naval design. In 896 he ordered the construction of a small fleet, perhaps a dozen or so longships that, at 60 oars, were twice the size of Viking warships. This was not, as the Victorians asserted, the birth of the English Navy. Wessex had possessed a royal fleet before this. Alfred's older brother sub-king Æthelstan of Kent and Ealdorman Ealhhere had defeated a Viking fleet in 851 capturing nine ships and Alfred had conducted naval actions in 882. The year 897 marked an important development in the naval power of Wessex. The author of the Anglo-Saxon Chronicle related that Alfred's ships were larger, swifter, steadier and rode higher in the water than either Danish or Frisian ships. It is probable that, under the classical tutelage of Asser, Alfred used the design of Greek and Roman warships, with high sides, designed for fighting rather than for navigation.

Alfred had seapower in mind; if he could intercept raiding fleets before they landed, he could spare his kingdom from being ravaged. Alfred's ships may have been superior in conception, but in practice they proved to be too large to manoeuvre well in the close waters of estuaries and rivers, the only places in which a naval battle could be fought. The warships of the time were not designed to be ship killers but rather troop carriers. It has been suggested that, like sea battles in late Viking age Scandinavia, these battles may have entailed a ship coming alongside an opposing vessel, lashing the two ships together and then boarding the craft. The result was a land battle involving hand-to-hand fighting on board the two lashed vessels.

In the one recorded naval engagement in 896, Alfred's new fleet of nine ships intercepted six Viking ships at the mouth of an unidentified river in the south of England. The Danes had beached half their ships and gone inland. Alfred's ships immediately moved to block their escape. The three Viking ships afloat attempted to break through the English lines. Only one made it; Alfred's ships intercepted the other two. Lashing the Viking boats to their own, the English crew boarded and proceeded to kill the Vikings. One ship escaped because Alfred's heavy ships became grounded when the tide went out. A land battle ensued between the crews. The Danes were heavily outnumbered, but as the tide rose, they returned to their boats which, with shallower drafts, were freed first. The English watched as the Vikings rowed past them but they suffered so many casualties (120 dead against 62 Frisians and English) that they had difficulty putting out to sea. All were too damaged to row around Sussex, and two were driven against the Sussex coast (possibly at Selsey Bill). The shipwrecked crew were brought before Alfred at Winchester and hanged.