While I can see how it's fairly easy for PC's to avoid death by Rum by tipping it out with a DC 10 Stealth check, I don't like how meanwhile everyone else is having a great time, getting drunk off Rum without them. We're PIRATES, darn it! I remade the Rum rules to better suit these concerns, while still keeping a un-ignorable penalty, especially for binge drinking. Please let me know if this works for what I'm going for (Even mighty Pirate lords can drink themselves to death if they're not careful!). Also, I completely ignored the normal rules for addicting drugs.
Abstaining - The penalty for selling or spilling Rum Rations is 6 lashes with the Whip, or 6 with the Cat for a second offense. Deliberately tipping away Rum on board a crowded ship without being seen requires a DC 10 Stealth check.
Ingesting - DC 5 Fort save or gain a minor addiction. Regardless, gain a +1d4 Alchemical bonus to Cha, and become Fatigued for 1d8 hours, and take 1d4+HD nonlethal damage (being addicted reduces this to 1d3 nonlethal damage).
Addiction - An addicted creature doesn't suffer from the Fatigued condition from drinking Rum for 1d8 hours. After the 1d8 hours, though, he must take another dose of Rum, or take 1 Con damage per hour for 1d4 hours. At this time, the creature must make a DC 5 Fort save. Success means their withdrawl is over, and the addiction is over. Failure means they continue to take 1 Con damage per hour for another 1d4 hours, before getting another Fort save. Each new Fort save after the first receives a +4 bonus, which increases by 4 each time.
Blacking Out - When a creature receives enough nonlethal damage from drinking Rum to become unconscious, they can make a Fort save (DC 10+HD) to remain conscious. They must make this save again after each hour, or fall unconscious. Each new save's DC is 5 higher than the last. A creature can always choose to fail this save. When they do fall unconscious, they must make a new Fort save (DC 10 + [amount of negative nonlethal damage]). Failing this save means the creature takes 1 Con damage for every 5 nonlethal damage they are below 0.