You might be interested in "The Mutiny of the Bounty" by Sir John Barrow for what went on between sailing ships and indigenous peoples of the islands they visited. I.e. quite a lot of sexual congress went on. In fact, one of the reasons for the mutiny was the sailors' unhappiness at being separated from their partners. When the mutineers returned, many of the indigenous women chose to accompany them on their trip to exile on Pitcairn Island.