GFC.
My first paragraph was the liability. I'm all for basic first aid. Apply presser, use a bag of quick clot, basic splinting, low flow 02, CPR, and the basic stuff. I also carry IV supplies and some more advanced life saving supplies.
In the second paragraph I was trying to say that not everyone is savable and you need to know the limits of what you have, how long till you get real help, and what if there is more than one accident.
The Good Samaritan Act cuts off at first aid and CPR with AED. You go past that your working off your certificate or your license and if your in that situation you should have your own professional insurance to cover your own ass.
My background was a paramedic, RN / Masters, Certified Hyperbaric Technologist, and a bunch of diver certifications. I made a ton of money on large dive boats. I don't know how many people I have lost inside a chamber that would have had a fighting chance at a half way normal life if I would have been able to grab the right stuff on the way into the chamber. I think my longest decompression was 20 hours and I worked on him most of that time.
I quiz all my passengers about there medical history's if were going to be more than 60 minutes from shore at any time.
NSAID are blood thinners not something that I would want to give anyone.
We subscribe to a service that allows us to reach ER doctors, trauma experts, and share information and get advice from them.
As to liability, we did assume some when we took our medical person in charge course as part of captain's training and we are insured both for things that happen on the boat and for our acting in those roles.
We don't profess to be doctors, but people with a little training who would make the best effort they could in situations. I'd rather accept the liability for trying than not to try.
There are situations in which the odds are against even a doctor when out to sea. However, there is also the ability with training and equipment to prevent some situations turning very much more serious. Cuts, infection, bleeding. IV's.
We carry equipment we hope to never have to use.
I say that everything we've encountered on board has been very minor, but then perhaps it's been minor because of what we carried. Washing out an eye and applying ointment to protect against infection, treatment of diarrhea, treating a cut from someone hitting their leg on a sharp edge of a dock and preventing infection.
We have been surprised at the number of people we've encountered at marinas who didn't even have bandaids or sunburn lotion or anything to sterilize a wounded area. Base what training you pursue and what equipment you carry on your cruising habits and needs. However, every boat needs something and we all need some training. I had never had a first aid class even when we started cruising. I lived in the city, never more than five minutes from help. My wife had it because of her profession as a teacher.
As to medical information, we basically have computerized forms for guests to fill out much like a doctor's office. One piece of information might be invaluable.