Smith, you are probably correct that drowning or near drowning are major or the major concerns on board overall but out cruising away from immediate medical care burns, sprains/fractures and stomach/intestinal upset are probably more of an issue.
Of course you're right, and my post was essentially didactic. We've strayed a long way from the OP, which was a shotgun full of "I'm gonna blue water cruise, what do I need?"
I was addressing one point with which I disagreed.
I find it difficult to tell someone what they need in their "first aid kit" without knowing their capabilities and what they're going to be doing. I did, in fact, recommend a first aid kit via private message a few days ago to a man who's a pharmacist with several other qualifications, and who's going to be the medical officer on an offshore race. In that case, I know what he's capable of doing and what he may be called upon to do, and I know what he'll need to do this. In a case like that, I can make specific recommendations. In his situation, this really isn't first aid, but may become definitive treatment.
There have been a lot of subsequent posts addressing CPR, cauterizing wounds, treating shock, and a lot of suggestions that are just plain nonsense.
The best thing the OP can do is learn some first aid, decide what he's capable of handling and is likely to be treating, and prepare a kit accordingly.