Some of them were even scientists
To quote:
William Dampier (1652 – March, 1715) was an English buccaneer, sea captain, author and scientific observer. He was the first Englishman to explore or map parts of New Holland (Australia) and New Guinea. He was the first person to circumnavigate the world twice, and went on to complete a third circumnavigation.
Bio here:
http://en.wikipedia.org/wiki/William_Dampier
And this novel looks like jolly good fun:
http://www.amazon.com/gp/product/0375423214/104-0103055-6557573?v=glance&n=283155