I am trying to work out why so many people put 'long keel' as a really desirable aspect of a blue water boat? I am going to suggest that it doesn't make much sense any more when you compare it with lots of more modern fin keeled designs - and it might be argued that fin keels actually make a lot more sense.
I am not claiming some great insight, but I have owned long keeled boats, and I have sailed across oceans in fin and long keeled boats so I suppose I have some experience and first hand knowledge. The key aspect as far as I can see is the overall shape of the hull - NOT whether the thing has a long keel or not.
Long keeled boats are often slower and I suggest in the whole sailing experience their ability to track and sail themselves is as much a hindrance as a help. I have this deep feeling that in the days before reliable autopilots and self steering, a long keel and the ability to stay on course was what sold the thing to the long distance sailor, but self steering (mechanical or electric) is very much more reliable nowadays and perhaps the the small occasional gain in directional stability is completely outweighed by the disadvantages of less then sparkling performance and the difficulties of maeuvering under power. Some people will say that the auto-pilot will be working harder, but I am not advocating a radical fin keeled racing machine - rather a more staid fin keeled boat that behaves itself in a seaway, in the same way that a long keeled boat sometimes can.
Futhermore, people setting off on blue water sailing seem to forget that the vast majority of their time will be at anchor and they will only spend a relatively short period of time in the overall scheme of things actually sailing across the oceans. Of course being safe and sensible when sailing the ocean is a good thing, but if the design of the boat takes much of the pleasure out of sailing around the area when you get somewhere, then what's the point? I have known people who through planning and care have sailed round the world and have never been in much above a force 6. The long keeled boat might heave to very comfortably, but I will suggest that a decent fin keeled boat can be just as comfortable if its well sorted and balanced. It also shortens passage time, and as the tedious part of the long distance passage is the days and days at sea, so anything that reduces that by a day or two gets my vote.
I have this suspicion that some of the people who advocate long keels are more armchair sailors than actual sailors. The wisdom is regurgitated because its what Slocum said when he sailed Spray etc etc. But times have moved on and so long as your fin keeled boat is not too radical and flighty downwind, then why not enjoy the extra volume inside, the predictable handling under power and sail, and the increased performance that come from a modern fin keeled boat?
Sadly some people's opinion of fin keeled boats is based on the fat bottomed horrors that are produced for occasional light wind sailing, and whose performnce under sail is an (predictably) unpredictable nightmare of broaches and rounding up in the smallest of gusts.
So there's my two pennyworth - and you can shoot me down at will. I'll take comments more seriously from those who have owned/sailed boats with both sorts of keel though!