The outriggers offer a particular but not complete protection from these attacks. One outrigger can be built for each completed harbour level, once the prerequisites have been met.
A pirate aggression does not herald itself. After it has passed the outriggers (during which the pirate may has destroyed some), the group of pirates disembark and move directly to your harbour. Only the basic soldiers fight the pirates, for the others need much too long get ready. Unfortunately, it is often the case
that some civilians die, too, because they have not sought shelter in time.
It may also occur that the pirates steal a few merchantmen to transport their booty.
The pirates only attack isles where the following conditions are met: