First, we are talking about the prehospital environment, not a hospital. At my level of care there are few really meaningful things that the law allows me to do. Oxygen is a comfort measure if nothing else and one of the few things I could do in this case that could make a differnce. I give O2 (even if is is 2lpm via canula) to almost everybody for those reasons.
Seconds, remeber what the intial question was. "Bearing in mind that a fishing vessel would not be carrying more than a required basic medical kit what would your actions be, the response time for the helicopter would be 15 mins to lift off and the at least 40 mins til on scene." these are fishermen without any real medical gear or capabilities (probably). If you were the medic on the helo, would you want them doseing the pateint with god knows what before you got there? It would probably be something like oral vicodin. If I were there I would want to give something, even if it would probably only take affect in abouot 45 minutes, just as the helo arrived and they wanted to give something like ms. Is a USCG Medic really gonna be familiar with drug interactions adn be willing to give anyhting on top of that? In hind sight, I would say no to all pain meds, except for the "feel good" measures that oxygen provides (probably not available on a fishing boat". Hall butt towards the helo!!!