I’m between boat shows right now. Our local Houston In-The-Water show has just ended and I have just had time to dismantle our booth and ferry the boats back to their slips before I depart for Annapolis and the boat show there.
Inevitably at these shows I, along with many other exhibitors get questioned about different styles of boat, about performance, layouts, construction methods and strength. “Is a Valiant a strong enough boat for an Ocean passage,” or “would you take an O’Day 30 across the Atlantic”? In these two extreme examples my answers would have been yes and no respectively but in most cases the answer is not so straightforward.
Of all the questions that arise at a boat show, two occur more than all the others put together. The first relates to the appropriate keel configuration for an offshore cruising boat and the second concerns how the mast is installed.
For many years books on the subject of cruising expounded the idea that a long keel with a keel hung rudder was the only suitable underwater shape for offshore sailing yet if you head on down to Islas Mujares or Antigua or any other cruising destination you will find relatively few cruising boats with full keels. It is clear that whatever has been written about the desirability of a keel running the full length of the vessel, few who set out and actually go places actually adhere to this. Probably the majority of cruising boats have modified fin keels and of these some have a skeg for the rudder, others do not.
A similar situation occurs with masts. Traditionally masts were placed directly on to the keel and it this or nothing that many books propound. But for years an alternative has been to step the keel onto the deck while providing a strong compression post below decks to transfer the load to the keel. Stepping a mast on deck maybe heretical to some but again, the reality is, a sizeable proportion of boats set out on long ocean passages, as I have done, with deck stepped masts.
This dichotomy between apparently well meant advice and the actual practice of cruising sailors bears some examination. Most who set off cruising are fairly prudent and careful sailors who in every other regard seem to err on the side of caution. They set out with a high level of safety devices, good navigation and communication equipment and a vessel loaded with spares and tools. Perhaps there are some advantages to a shorter keel or a deck-stepped mast, which these folks feel, is of significant importance.
In reality, the choice that these sailors are making echoes the decisions made by the designer of the vessel. Is it better to be able to beat more easily off a lee shore with a modified fin keel than to be able to careen your boat on its long keel? Is it more important to be able to easily maneuver your boat when getting in to a tight slip in the marina or does having a vessel that will track with the helm tied off seem more desirable? Is it better to have a keel stepped mast or does the appeal of having a leak-free deck and a mast step that is unlikely to corrode (as many masts do where they sit in the watery bilge)? For every advantage of one design there seems to be an equivalent with the other. Which is why boat designs are continually evolving as boats are sailed more and used differently. As the materials that are used to manufacture the majority of cruising boats has changed, so have the ideas as to what features should be included in a modern cruising boat.
But this is not to say that all long-keeled boats are old fashioned or that all those with a modified fin keel are appropriate for ocean passage making. Because in most cases it is not the choice between full or modified keel, deck or keel stepped mast that is important but the actual construction used in the manufacture of the vessel. And, not surprisingly, this is also the most important consideration concerning those other critical areas of a boats manufacture that are less easy to see. A boat may have a full keel and a keel stepped mast but if the keel is not attached securely, or if the rigging is undersized, or if the hull is not thick enough, or the bulkheads not secured strongly enough, then the seaworthiness of the whole vessel has been compromised. A boat may have a skeg mounted rudder but if the skeg is itself not built strongly enough then the rudder has been compromised. An encapsulated keel is only as strong as the fiberglass that surrounds it; a bolt-on keel dependent on the strength (and corrosion resistance) of the keel bolts. A deck to hull joint that is poorly done may not be obvious when a boat is new but it may begin to leak when the boat gets used heavily and worse, it may be the site of a tear in the hull side which results in the vessel sinking.
Over the years I have been tempted more than once by thoughts of long-distance offshore racing but each time I consider it I recall the numerous instances of modern racing sailboats losing their masts, or keel in heavy weather and as a result some sailors have lost their lives. These boats have been designed to sail fast and in order to attain an edge over the competition designers (or perhaps the skippers) have cut down on the strength and weight of rigging such that often a rig is designed to carry less than 100% of the anticipated load. On a cruising boat designed with prudence in mind this figure could well be over 150%. Keels are designed to be so short and deep that to merely touch bottom or strike an object offshore is likely to damage the hull.
For many boat buyers, the attraction of a vessel with a long keel and a keel-stepped mast is not so much the features themselves but an assurance that a boat so designed must be well built for offshore sailing. It is considerably more difficult for a relatively inexperienced buyer to look at the majority of boats that are available, new and used, and to be able to tell which are built strongly enough for offshore sailing and which have been built more cheaply and less well. But to help in this here are a few guidelines that can be used to assess a vessel’s suitability for offshore sailing. Of course we all have to decide on the risks we are prepared to take when sailing offshore and the strength of the vessel is only one of these decisions. There are very few absolutes here and while I may feel comfortable sailing offshore on a particular boat, others may not. And in extreme circumstances of weather and seas there are few, if any, boats that will hold up for long however strongly they are built.
Displacement to Length ratio
As a broad guide to a boat’s strength, the ratio of the boat’s displacement (weight) to its waterline length (LWL) is often used as follows:
Displacement / LWL ratio = Displacement (tons) / (0.01 x LWL in feet)3
As a rough guide the figure obtained can be used to determine what type of boat you are looking at. Displacement / length ratios over 325 will typically indicate a heavy displacement cruising boat; a figure between 200-325 a moderate cruiser/racer and a figure of less than 200 a light racing boat. But these categories are not absolutes and different books will but the boundaries between one category and another in differing places. And in the end, this formula tells you nothing about the actual construction of the boat. Its use is based on the idea that heavy displacement boats are likely to have heavier, thicker hulls and larger masts and rigging than light displacement boats but this is not necessarily so.
Observation of mast and rigging size
If you take a particular length of vessel and walk the docks of your local marina, it is instructive to observe how boats of the same approximate length have widely different sizes of mast cross section and rigging diameter. By making comparisons you will be able to see which boats have been designed for tougher conditions than others.
Hull to deck joints
How well the hull and deck are joined is clearly critical to the integrity of a boat but finding how well this is done is not always easy as the join is usually covered on the outside with a cap rail or rubbing strake and often on the inside with trim or a hull liner. Check how closely the bolts are spaced along the join but also look at the size of these bolts and see if the joint has been fiberglassed or not on the inside. Good places to look are in cockpit lockers or the chain locker as there is often no trim hiding the joint.
Hull thickness and composition
Without taking core samples of a boat at different parts of the hull it is impossible to be certain how thick a hull is or how well it has been made (hull thickness itself is not enough). But by looking at areas around the through-hull fittings you may be able to get some idea of how thick the hull is at these points. Another, somewhat arbitrary, observation can be made when a boat is hauled out the water and lowered to sit on its own keel. If the boat appears to sink on to the keel or if the hull sides bow then you will have some idea of the strength of the hull. Neither of these should happen on a well-built offshore cruising boat but may well do on a lighter less well-built boat or on a performance offshore racing yacht.
What is important when you set out offshore aboard a cruising boat is that you are aware of how well it is built and not just the design features that it incorporates. But in addition to having confidence in your boat from a knowledge of its sound construction you will also need to be assured of the appropriateness of the skipper for offshore sailing. Are they as well prepared for offshore sailing as the boat?