Shoal Keel and blue water?
Depends on the boat and several factors in its design. One solution is a Keel/Centerboard (K/CB). There are several offshore boats where this is executed well and has some advantages over a fixed shoal draft boat.
I have a Wauquiez Hood 38 K/CB, designed by Ted Hood (who certainly knew what he was doing). The K/CB design can also be found on some high end boats like Hinckley, Alden, Little Harbor (Ted Hood), Bristol''s as well as some Asian bluewater boats like the Cheoy Lee Pedrick 41.
Speaking for my boat, the Hood 38 (sisterships are the Bristol 38.8 and Little Harbor Hood 38) has a 50% ballast to displacement ratio and a angle of vanishing stability (AVS)of over 160 degrees (by my calculation...but I am no expert). Many many of these boats and her sisterships are bluewater sailed world wide and circumnavigated.
Having a keel, the boat does not need to have the board down to sail well. In fact, she will go to 30 degrees apparent w/o the board. She can outpoint a Navy 44 (I have been told) and several other racing boats with the board down. Also, I have not found her overly tender, as has been reported for some k/cb''s.
I think of the k/cb option like the variable wing geometry of an F-14 (Jeff H will have a field day here, I know, but still...) (and Jeff H helped me to select this boat, even if it would not be his personal choice, for which I am very thankful)....Going fast, whether hard on the wind or on a broad reach, the keel serves as a very efficient foil and you don''t need any more surface area..or DRAG...thus you keel the board up and zing along. At slower speeds (<3.5 knots) I put the board down to reduce leeward slippage. In a blow, having the board (800lbs) down lowers the cg and increases stability. Going to windward, you put the board down to create a greater foil. Its really quite a nice concept if you know how to use it.
Offshore, the advantages of the K/CB option, as executed on the Hood 38, are greater AVS and a shallow keel the boat cannot "trip over". You can increase, adjust or decrease your foil to suit the various conditions. The longer keel, in a K/CB, has superior tracking ability, and contributes to a well balanced helm. It CAN BE like having the best of all worlds: the tracking ability of a full keel, the pointing ablity of a deep fin and shoal draft.
Of course, all boats are compromises and I should give Jeff a break from typing and list a couple here: The Hood 38 is a heavier boat than other 38''s...the downside of this is greater sail area to handle and a greater mass of boat to manage...this was pointed out to me by JH and is absolutely true. I am lucky to still have enough strength and ability to singlehand this boat. The K/CB option means also inspecting the cable and pennant on a yearly basis. Most folks put on extra cable and cut off a few inches every yr or so, at the board.
Hope this helps.
[Note to Jeff: Have not had a chance to chat in a while, but wanted to say thanks for all and, hope you had a good summer on Synergy and let you know how much I am enjoying Invictus. I think she is a great boat, I am very pleased with all aspects of her. There is a place at the helm for you anytime. Duane...place for you and your lovely wife too]
Now I am off to stay aboard for the weekend. Bye.