Designing for Offshore

Offshore cruising in small boats, for pleasure, is a very recent development in maritime history, and has little precedence prior to this century. This is barely long enough for purpose-specific types to evolve "naturally" in the manner of indigenous work boats. Therefore one must make a bit of a study of the matter before one can know what the optimum boat is to be, for one's purposes. If you go to three boat builders asking each for an offshore cruising boat, you may get three very different boats.

We have fairly broad tastes in boats ourselves, and the reader will perceive that there is a seemingly wide range of boats in this catalog which we have called suitable for offshore sailing. However, we have tried to differentiate between those boats that are "suitable" for offshore and those which are "optimized" for it. We will attempt to explain the characteristics we are referring to in this manner, below.

Now and then we encounter people who seem to have no fear of the sea or its hazards. We are afraid for them. When we accidentally have such a person aboard our own boats, we are afraid of them. It is good to control fear, and bad to lose control to it. It is good to know the exact nature of the things you fear, and bad to have nameless fears. Having exactly the right amount of fear, knowing its nature, and using it correctly is the mark of a good seaman.

Many are the defenses we read and hear of for taking non-offshore-specific boats to sea. We will fight tooth and nail for people's right to take whatever boat they want to, offshore. However, if a person does not fear his vessel's inadequacies he is not qualified for offshore sailing, and in particular he has no excuse for taking innocent people offshore with him.

There is no greater relief from fear or the need for fear than justified faith in the vessel that you take to sea. Offshore voyaging need not be an exercise in risk-taking. It has been well proven that a good boat, properly handled, can endure terrible conditions offshore. There seems to be little excuse for settling for something less. It seems inexplicable that anyone would want to do so. The boat need not be large, expensive, or fabulously well equipped. She just has to be up to the job.

Adequate strength is the first priority. The boat must not come apart. It is a fact that many contemporary boats are too lightly built for offshore work. However, it is also true that once adequate strength has been obtained, adding more and more at the expense of weight is counterproductive. The boat is partly a fortress, it is true, but it is also a vehicle, and her ability to travel fast in the desired direction contributes directly to safety.

Many boats are adequately strong in the hull, but inadequately strong in other areas, hatches and deck structures being the main offenders. In the worst conditions there is little difference between the structural demands placed on the hull and those placed upon the deck, cockpit, cabin trunk, ports, and hatches. All are subject to heavy impact from water, and all can result in catastrophe if they fail. We design all these structures to be as strong as the hull, for this reason. Cockpit wells, which we often eliminate completely for the gain in deck space, interior volume, strength and simplicity, must be small, so their flooded volume does not significantly alter the vessel's trim or stability.

While offshore boats are typically of heavy displacement, it is perfectly possible to design a light-displacement boat that is safe offshore. The chief objection to them is that they have a quicker, jerkier motion, which most people find uncomfortable and tiring. This effect can be held to a minimum if the boat is narrow and relatively V-shaped, with a deep keel, which are all good characteristics for the safety of the vessel as well. Most light-displacement boats are given shapes that encourage surfing, but for offshore use it is important to prevent surfing, which can cause a loss of control. Even so, the light displacement boat is apt to be too fast when running off. Therefore, rudders should be large and mounted on the keel or a large skeg, probably mounted under the hull rather than on the transom, so as to prevent ventilation from the surface. The only advantage to the light displacement type for offshore use is in her ability to carry full foam flotation with minimal loss of interior space. This is so easily accomplished that it is a mystery to us why more light displacement boats don't have it. Since a fast, self-righting, unsinkable boat is possible for those willing to accept the motion, this removes any argument in favor of the offshore multihull, as far as we are concerned.

Heavy displacement is the "natural" choice for offshore use. The comfort level is much greater, and conventional proportions produce the right combination of stability, self-righting, motion damping and non-surfing behavior for maximum average speed and safety without gimmicks. Foam flotation usually occupies too much space to be desirable. However, there are inflatable devices available which, while they are more like the sort of "gimmick" that we usually avoid, should be at least as reliable as life raft technology. It would seem that it might make sense to work in some foam flotation where it is not too inconvenient, making the inflatable flotation easier to fit in, afford, and utilize.

We should point out that we are seeing a generation of contemporary heavy displacement boats which do not take good advantage of the type. They appear to have been drawn by designers used to light displacement and are merely forms of that type, made heavier by lengthening the keel. If you look at a long keel boat and find her to be flat floored amidships and aft, she will tend to be slow in light air due to excessive wetted surface. She may also be excessively fast when running off in a gale due to a tendency to surf. It is also common for her to have an uncomfortably quick motion. A heavy boat should be quite V-shaped throughout her underbody to take advantage of the type. It is more appropriate for the light-displacement offshore vessel to resemble a heavy displacement form in section than the other way around.

Heavy displacement is compatible with other practical considerations relevant to long-range voyagers. The type allows more weight to be devoted to hardware, rigging, and other details. This allows them to hold up better over long-term hard usage and accidents in port, sometimes far from sources of spare parts or skilled labor. So when a vessel is to be optimized for offshore, we recommend heavy displacement. When she is only to go offshore occasionally, either a light or heavy vessel can be made to serve, if appropriately designed and built.

Once you have established that your vessel is strong enough in all respects, fully self-righting, and property proportioned, the remaining offshore characteristics are more people oriented.

It has been well demonstrated that if a vessel is well found, and can determine her position accurately enough to avoid hazards, the primary remaining danger is in the physical and mental well-being of her crew. Exhaustion and hypothermia are the primary concerns, and both are most directly addressed by reducing the need for the crew to perform work on deck during difficult circumstances. We place a high priority on the ability to control the sails, helm, and vane gear from a protected location such as a bubble hatch or wheel house. Most of our boats feature one or the other, whether they are meant for inshore or offshore. Frankly it is a mystery to us why so many people spend so much for boats without achieving the profound positive impact on comfort, let alone safety, that these items provide. Probably it is because the Chinese lug rig is best suited for this type of "remote control". Unfortunately, despite its well-proven nature and the universally high praise it receives from those who have it, it is unusual and primitive-looking to the average person. Convention is a powerful influence. Conventional rigs can and should be made to be controllable from a sheltered position; it is just more difficult to accomplish.

Equipment also plays an important role, and nowadays we would not voyage without such affordable items as GPS, an EPIRB, etc., but these are not design matters, so we will not get into them here. The reader is urged to contact us for free advice.