There are many criteria that make a boat suitable as an offshore cruising yacht, and equally some that make a vessel less than ideal.
An easily handled sail plan
Even if you intend to sail with a large crew on passages involving no more than an occasional night at sea, an easily handled rig will pay dividends. There are ways in which a passage of this length is tougher than a longer voyage: when you're at sea for a week or more, there’s time to adjust to watchkeeping rotas and for sea-sickness to subside. Therefore, even if you have a crew of six or eight people, there will be times at which only one or two are capable of standing a watch at any one time. These are the times at which you will really appreciate a quality roller headsail that retains good shape when partially reefed and mainsail reefing that can be operated by one person in the cockpit. Knowing you can reduce sail easily will also help give you the confidence to choose a boat that will sail well in light airs.
Light weather performance
You are statistically far more likely to encounter calms than gales, so if your boat requires 10 knots of wind to get moving properly you will inevitably spend a large amount of time motoring or, at best, motor-sailing. Therefore, a boat with a large rig and sail area/displacement ratio, combined with modern reaching and running sails for light airs, is to my mind far preferable to one with a conservative small sail plan.
Heavy weather capability
While good light airs performance will enhance your general enjoyment of sailing the boat, it must still be able to take heavy weather in its stride. A boat’s angle of vanishing stability is an important factor here – if the boat is inverted in breaking waves you need to know it will quickly pop back upright. Again, traditional narrow and relatively heavy boats score best on this count, although their lower form stability means less wave energy is required to invert them in the first place.
In addition to a high angle of vanishing stability, it’s also important to avoid downflooding in which the boat is filled up with water entering via a hatch, companionway or locker lid. While modern yachts universally have self-draining cockpits, many have low thresholds at the companionway to make access to the cabin easier. However, this means that if the cockpit is flooded by a wave, potentially dangerous amounts of water can get below deck. This can be solved with a washboard fixed in place up the level of the side decks in heavy weather. It’s also worth checking whether cockpit locker lids really form an effective seal, and whether the lockers drain into the main bilge, with the potential to allow unlimited amounts of water into the boat.
Being prepared for heavy weather also means efficient storm sails – ideally a heavy weather and storm jib that can be hanked onto a removable inner forestay, plus a trysail on a separate track. These can be added to a boat that is otherwise suitable for offshore sailing, so don’t worry if they are not in the inventory, providing the price is right.
Before the advent of reliable and efficient self steering systems, whether windvane or electronic, directional stability was seen as a key criteria for anyone sailing long distances. This was a key argument in favour of long keel craft that were slow to deviate from their course. Today’s designs have a much shorter keel, but benefit from a significantly more efficient rudder, which means that an efficient self-steering system can steer safely in almost any conditions.
Handling in port
This is an element that is all too easy to overlook, yet it is one that historically has dashed the dreams of many of those who aspire to sailing longer distances. A boat that’s a nightmare to park makes for a stressful start and finish to every trip, whether it’s a 20-mile sail to the next port or a 500-mile crossing of Biscay. By and large, boats with a short keel, but deep draught, and a large rudder will score highly here, whereas those with a long keel are more difficult to manoeuvre.
However, there is one area in which a traditional heavy boat with a long(ish) keel scores highly: comfort at anchor. When lighter boats are yawing wildly around their anchors in a rising breeze, a heavy boat will be sitting relatively still. This has two advantages: life on board will be both more comfortable and less stressful since you will have less chance of dragging the hook.
It may sound odd to choose an offshore yacht on the basis of its interior, but sadly many boats fall short in this respect. A lack of decent sea berths fitted with lee cloths, for instance, will soon take its toll on crew strength and morale. The same applies for a galley in which it’s impossible for the cook to wedge him or herself in position.
Similarly, many modern wide-bodied yachts have large open saloons. While these are undeniably great in harbour where they allow crew to move around without bumping into each other, it can be a different matter at sea, when attempting to move 12ft across the boat to the high side can be serious challenge. More seriously, falling in the other direction can result in injuries such as broken ribs. Look for boats with plenty of hand-holds placed close together, and where open areas are divided into smaller zones that make it possible to brace yourself in position when the boat is heeled.