A bottle of rum : a Spider John mystery / Steve Goble.

Enhanced descriptions from Syndetics:

August, 1723 - Spider John Rush believes he has escaped piracy forever. Enjoying rum and chess in a dark Lymington tavern, he dreams of finding passage to Nantucket to reunite with his beloved Em and to finally get to know the son he remembers only as a babe in arms, though the lad must be dreaming of going to sea himself by now. But when a lazy taverner is stabbed to death, one glance at the victim tells Spider the pirate life has followed him ashore and he cannot possibly ignore this bloody crime. The wise maneuver would be to run before authorities arrive, but Spider is denied that choice because he's already deeply, connected to the crime - he fashioned the murder weapon with his own hands. The knife was a gift to a young man, one who ran off with the notorious Anne Bonny before Spider could drag him into a respectable life. Soon, Spider John and his ancient shipmate Odin are dodging accusations and battling smugglers on a trail that leads to a madhouse where patients are dying on