Suppose a West African kingdom on developed seafaring technology capable of traversing the Maghreb and into Western Europe in the early 10th century AD. The ships in question resemble large trimarans with a large, long Carthaginian-style hull that has multiple oars and sails for propulsion.
Due to the invention of these ships, the West African pirates set sail to search for power, glory and wealth other than going fishing with these ships - they venture northwards in search for it. Arriving at a small fishing village in southern Ireland, they raid the village for loot and spoils.
The following years, these Cartagines (term for West African pirates) continued their raids on Western Europe, devastating Iberia, France, Britain, Ireland, Italy and Germany.
What would be the effects of West African pirate raids on Europe?