Which Island Packet?
I think this is a good example of trying to prove that pastachio ice cream is unversally better than strawberry. Like most things in sailing, there is no one size fits all answer that will please everyone and that even extreme differences between very experienced sailors (in this case two sailors ho have sailed for over 40 years) can be extremely divergent, even when the basis for a particular point of view is the same.
For example, when BillPjr says,"Very experienced are generally sailing traditional full keel, moderate to heavy cruising boats." I would say that used to be very true but no longer seems to be the case as many (and frankly most that I come in contact with) of us experienced sailors have tried owning,"traditional full keel, moderate to heavy cruising boats" and moved on to better performing, more easily handled, less tiring, lower drag designs.
Similarly, the right amount of draft is best chosen on based on the venue. If you are predominantly going to be spending time in Florida or the Bahamas then there is a practical draft limit of 5'' to 5''-6" that certainly makes life a lot easier. You can cruise these venues in a deeper draft boat but it means greater viglience and less convenience. On the other hand if you are predominantly going to be cruising offshore, or in a venue like New England, the Pacific Coast, Europe, or the Carribean, greater draft is a real asset and far less of a liability.
Then there are matters of nuance.... "Compared to full keels, most fin keels are nervous nellies sailing or at anchor." I think that I would agree with that. There are a lot of really badly designed fin keeled boats out there, and frankly there probably are more poorly designed fin keelers than there are well designed fin keelers. Nothing is more twitchy than a poorly designed fin keeler, especially one with an attached rudder as was popular in the CCA era.
I would also say that there are a lot of very poorly designed long and full keeled boats out there and that these tend to be nearly equally as twitchy as a poorly designed fin keel boat, and because of the higher helm loads they require much more physical energy to keep on track than a more lightly loaded spade rudder.
On the other hand, a properly designed fin keel boat will track with any full keel boat and will be easier on the crew as well. In my
experience owning, delivering and sailing full keel boats, sailing even a well designed full keel boat downwind in big following seas is a workout compared to the ligher more responsive helm of a well designed fin keel boat. Some of this is clearly preference, some of this is the boats we have experienced (it does not sound like Bill has experienced a well designed fin keeler).
When you talk about comparatively small boats, (by which I mean boats under 50 or so feet) by an large the foils (keel and rudder) play a pretty small role in tracking. Generally staying on course is a matter of the dynamic balance of the rig, hull form and underwater foils. In most of the tank studies that I have read on this matter, and in my own experience, full keel boats do not seem to offer a real advantage in heavy following or quartering seas. Their larger keel area means that there is more area for a wave to act on and twist the boat off its course. Like most things in sailing, full keels both giveth and full keels also take it away.
Then there are the collateral issues that cloud the merits of the discussion. Many, if not most, of the fin keel boats that are out there were produced in a the IOR era and carry with them issues related to the choice of hull form and rig. The twitchness of these boats come from transient changes in immersed hull shape and rigs that are proportioned such that the rig is less conducive to assisting with longitudinal stability. Fin keeled boats are generally lighter (but not always) than a similar length full keeled boat, and also typically carry a greater amount of sail area for their displacement than full keels. The combination of these items have greatly contributed to the popular misconceptions about fin keel boats within the more conservative members of the cruising community.
And lastly there are simply opinions that may or may not have real basis. "Windvanes don''t like following seas and that problem is greatly magnified with fin keels." I strongly agree that windvanes do not work well down wind and in following seas, but equally strongly disagee that the problem is magnafied with a fin keel boat. In fact my experience with vanes is just the opposite finding that vanes have a much harder time with the higher helm loads and large helm angle changes required to keep a long keeled boat on course vs a fin keeler.
Similarly, I would also disagree that fin keeled boats, "like to snag anchor lines when using two rodes in a current". You hear that from people who favor long keeled boat, I have never had an anchor rode foul a fin keel (even when using a Bahamian moor when I frequently anchored in the strong shifting currents of Georgia) or even heard of that actually happening. The closest thing that I encountered to that was with one of my full keeled boats where the anchor rode slid along the bottom of the keel and wedged between the rudder and its bearing jambing its rudder. In fairness, had the boat been a fin keeler the results might have been a line between the keel and the rudder. All of that said, with the current trend in using all chain rodes, or with the precaution of weighting the rode below the depth of the keel to prevent snagging that makes sense no matter what kind of keel you have, that should not be an issue.
Lastly, as to the opinion of the "resident expert around here", I would love to hear his opinion on this but unfortunately, Jack on Whoosh is off cruising around Europe on his fin keel/skeg hung rudder boat.
I also want to touch on the PHRF rating discussion. PHRF ratings are generated at the average prevailing wind that a race might be held in a given region. In most venues that is a wind speed around 10 to 12 knots. That range of windspeeds tends to minimize the differences in speed between boats and so it masks the issue to some extent. Lower drag boats tend to have their greatest speed advantage over higher drag boats at the lighter end of the wind range and at the upper ends of the wind range. On a long passage this can make a huge difference in the duration of the passage and amount of fuel required. While I generally avoid annecdotal evidence in these discussions, I will mention two good items for comparison on this issue. The first, and probably the less valid was a story that was told by a fellow who single-handed a 38 foot sistership to my boat from South Africa to the Caribbean. He left South Africa in company with a heavy and traditional 50 plus footer that rated something pretty close to his boat. It was a trip sailed initially in very high winds and high seas, and then in the light air of the Duldrums and then more moderate conditions in the Caribbean. The 38 footer made it to the Carribean over a week ahead of the heavier boat having burned something less than 17 gallons of diesel. The heavier boat was low on fuel having motored through the Duldrums. I think a better indictor is the Caribean 1500 results. I find these interesting in terms of the kinds of boats people tend to use and the passage times. As a general rule, the faster boats for their length do better than their ratings, but there is always a few heavier, traditional boats that do better than their rating would suggest, and a few lower drag boats that really do terribly.