Here is an interesting addition to the topic of foreign seamen in Nelson's Navy: Captain John Perkins was not only black, but achieved the rank of post-captain, a superb achievement. There is a short (and expensive) biography available on Amazon:
http://www.amazon.co.uk/John-Perkins-Ro ... 6136990865There is also an entry on wiki but each time I try to post it here it goes wrong. Use Captain John Perkins RN as a search term and see if it works then.
Digression: Tony - I know you don't like the term 'Nelson's Navy' and I understand why. It's very useful shorthand,though, for 'the Royal Navy of the late eighteenth century' or 'The Royal Navy during the period of the Napoleonic Wars.' I suppose 'Georgian Navy' is equally fitting. Perhaps we should encourage the use of that term?