To Jeff H
I am flattered by your addressing your question to me personally but I am not sure that I am the right guy for this. By preference I am pretty much a coastal cruiser. While I have spent time offshore, it''s just not my preference. I have never had any desire to do a circumnavigation but hope someday to cruise at leisure the Mediterranean, Caribbean and the Baltic as well as the U.S East Coast. I also have a very strong bias toward performance over interior comfort and comfort underway vs. comfort at the dock or anchor. This pushes me toward a point of view that is anything but mainstream when it comes to offshore boats.
There really is no such thing as "the ultimate offshore sailing boat." Each boat has their own compromises and biases and each owner has their own set of priorities, and prejudices. There might be one ultimate offshore sailing boat for each individual and there may also be one boat that appeals to any individual sailor as there one and only ultimate offshore sailing boat. Whether it really is or not is another story.
All of that said, I am actually in the process of buying a boat that I think of a good long distance cruiser (as well as coastal cruiser) so I will refer to my own process from time to time here as well.
In making the basic decisions about what size and kind of boat to buy as a long distance cruiser I had ruled out multihulls because I cannot afford to purchase on of a size capable of going any real distance and in the light air of a Chesapeake summer monohulls are actually faster.
So starting with displacement, if you look at traditional cruising oriented books and articles, there seems to be a general recommendation that a distance cruiser should weigh approximately 3 to 5 tons displacement per person. (Traditionally 6 tons was seen as being a practical maximum over which you would really wear out a crew.) So in theory a boat for a couple in classic literature should weigh in at 12,240 lbs. to 20,400 lbs. with 24,450 as a practical maximum.
Some things have changed since then. We have better hardware and electronics, which permit a person to handle a heavier boat more easily. Better deck hardware and roller bearing blocks make it easier to handle bigger sails and low friction steering gear and the lower steering loads of fin keel spade rudder configuration make it possible to person to steer a larger boat for longer periods. We expect more features on a boat, which also adds weight. We motor more today than our predecessors and so need to carry more fuel which adds more weight in fuel and bigger engines (which may also be why we motor more). This is partially offset by the ability to build stronger and lighter boats than our forefathers.
Because of my performance orientation, I personally favor a boat with an all up weight closer to 12,500 lb. or so displacement for a long distance cruiser for two people (which works out to a partial load weight of about 10,500 lbs.). Today, you see more and more people typically opting for displacements of 17,000 lbs. on up to 24,000 lbs. and beyond. As I have said before, I strongly believe that weight in and of itself does nothing good for a boat. It does not make it strong, or more seaworthy, or stable, or comfortable, or able to carry more gear and supplies. It simply adds weight. And weight hurts speed and makes a boat harder to handle in all conditions.
In my conversations with designers of modern (and I emphasize the word "modern") long distance cruisers, a Displacement/ Length ratio of about 160 based on a partial load weight seems to be about a practical minimum and that would result in a boat with an approximately 31 foot waterline. That is how I arrived at a 38-footer being about ideal for my needs.
If you look at the more typical calculations of a displacement between 17,000 and 24,000 lbs. and the more common L/D of 200 to 300 that yields a waterline length between 31 and 37 feet or an overall length of 38 to 42 feet or so. To me a 40 -42 feet boat is a lot of boat to handle for two people. I know it is done routinely but I also see boats this size being motored or not out sailing on a lot of days when I see the water full of smaller craft under sail. To have any kind of decent performance you need pretty deep draft or the complexity of a centerboard or wing keels.
Then there is rig. I personally am a big fan of the fractional sloop rigs. You see a lot of this rig in areas of the world with big winds and a fair amount in light air regions as well. The nice thing about the fractional rig is the speed and precision with which you can depower without reefing or changing sails. It really allows a quick throttling up and down for the conditions. The smaller headsails on a fractional rig are much easier to haul about the boat, store and to tack. With a fractional rig, you have a better chance of getting by without an overlapping jib through a wide range of wind speeds and you need few headsails to suit the conditions.
That said, in more traditional circles, cutters seem to be the favored for long range cruising. I really hate dragging a forestaysail across the jibstay, especially in any breeze at all. I have also gotten caught aback when a forestaysail hung up on the jibstay in high winds. To me it really makes sense to have the jibstay de-mountable so that it can be stowed at the mast in normal conditions. I also prefer a knockabout cutter (no bowsprit) as it is not a great idea to have the mast solely supported by a forestay tacked to the end of a bowsprit.
For me there are a number of items that would be deal breakers.
-No teak decks!
I know of no way to build a teak deck that is a permanent solution. They are beautiful to look at but they are a major expense when they go bad which sooner or later they will.
-No full keels.
To me they represent too much of a compromise in sailing ability; speed, windward ability, maneuverability and loads on the helm. I know that there are strong arguments for both full keels and fin keels. I just happen to have no use for full keels in my idea of voyaging under sail.
-No encapsulated keels.
Having tried to repair them when they have been damaged I would not buy a boat with an encapsulated keel. That said there are some good arguments against keel bolts. That said, I have replaced keel bolts and repaired a water logged encapsulated keel. The keel bolts can be repaired good as new. Once an encapsulated keel has delaminated from the ballast as sooner or later it will there is no way to return that boat to full structural integrity.
So where does that leave us? Well, if someone said name one boat that makes sense for a couple to sail around the world, I would probably say a Valiant 40. It''s not my kind of boat but it is an easy first answer that would work for most people. I really like Brewer 12.8''s centerboard cutters, and they would also fall very high on my list. My father has had one for a number of years and I have been very impressed with these boats. (He''s thinking of selling his before too long.) I think that under $100K the Peterson 44''s are really nice boats and should really go the distance. Another boat that has always looked good to me is the Norseman 447 (and I think there was a 43 foot version has always looked good as well).
If I were going higher performance, wanted a bigger boat, I had the money and wanted a new boat, I think that the Morris 454 and the Aerodyne 47 both look very interesting, as does the Hunter HC 50. The Hunter is not your local cruisers kind of boat but is a serious offshore high performance cruiser constructed to a very impressively high standard. If you were going for something used, Bruce Farr designed a series of fast cruising boats back in the late 1970''s and early 1980''s. these were mostly constructed as one-offs, but in many ways they are my ideal cruising boat. There were 38''s, and 40''s, as well as, a 42, 44, and 48 that I have hear of. I was aboard a 52 that just knocked my socks off.
I am sure I am overlooking many good boats and I don''t know if this is helpful to you but it does represent my thoughts on the matter. Good luck to you!