many max were impressed (the navy actually sought them out as many manx were well used to boats) - the death rate was it seems quite high - look at the will summaries on Manx notebook -- the Manx could also be 'impressed' if they were caught smuggling - one option the court often gave was for them to 'volunteer' for the navy (apparently being a volunteer gave some perks over being forcibly impressed).

There may be some documentation in UK Nat Archives but it would appear (and I have a few examples in wills which included letters from their shipmates) that those pressed often gave false names (eg their mothers maiden name or eg richardson when father was richard) as that way if they deserted and then caught again they would not be immediately recognised as a deserter