01 MAY 2007
Photo courtesy of Bull Sworn Marine Surveyors S.L.
More transportation on deck Securing
It is now customary to use strong webbing straps of polyester or nylon fabric with hand-ratchet tensioners when securing yachts. Such straps have the advantage of being light and easy to handle and are very suitable for the lashing of unprotected items, avoiding the possible chafing and excessive point pressure by wires, chains and ropes. However, web straps have the disadvantage of being more elastic than chains and wire, and may slacken during the voyage. If they are very long – which they often are, as they have to reach fixation points on main deck from a cargo item on the hatch covers – they may even be difficult to tighten sufficiently. They are also vulnerable to chafing, so sharp corners and edges must be avoided. In combination with chains, such straps may be kept to short pieces thus avoiding excessive stretching. Checking the lashings regularly for tightening up on voyage is a part of the seaman’s job, but this may be difficult or impossible when it is most needed: in bad weather. To the mate who calculates the strength of the lashings in accordance with the weight and size of the cargo, the GM and the rolling periods of the ship, the webs have the disadvantage of not always being of a known breaking strength. It is not particularly easy to secure a yacht to the deck of a cargo vessel, especially if such a cargo is not customarily handled by the people involved. First of all the yacht needs to be supported by a cradle. Sometimes yachts are supported by stacks of wooden pallets or loose wooden blocks, which is certainly not sufficient for any hard weather movements. The condition of the cradle is also an issue, as it must fit the yacht and be of sturdy and good condition. The cradle must be secured to the deck and shored off to avoid any movements. It may even be necessary to weld supports to the deck for such a purpose. Depending on the size and shape, location, etc., it may be necessary to attach the yacht both to the cradle and to the ship, to avoid movements. There have been cases where cradles have been saved, well fastened to the deck, while the yacht has worked itself loose and dropped out and been damaged.
Photo courtesy of Bull Sworn Marine Surveyors S.L.
A cargo vessel has strong fixation points, but the yacht to be secured may not have any, as strangely as it sounds. One would think that items such as fairleads and cleats on the deck of the yacht would be strong enough fixation points, but often they are not. They are designed for mooring the yacht when the yacht is afloat in a protected harbour, when the direction of pull is horizontal and the pulling forces are eased by some elasticity of ropes or tension-dampening devices. Some luxurious yachts are certainly made more for comfort and style than for strength, and more than once mooring cleats have been pulled straight out of the deck, distorted and broken. Weaker structures, like handrails, which are also used to tie up to, will, of course, be damaged even more easily. So, inventive crew members may be looking for other points of attachment and thruster tunnels and propeller shafts may seem nice alternatives. Stainless steel propeller shafts bend rather easily, however, and it may be discovered that attaching ropes or web bands to a shaft is not such a good idea after all. To offer protection from the sea, the best is of course to carry any cargo in the cargo hold, although finding strong fixation points on the yachts and avoiding damage from other moving cargo will still be a problem. It is advisable not to store an unprotected expensive yacht too close to other cargos, to avoid damage if just small movements should occur, but one does not always have such an option. Due to the value of the yacht and its vulnerability, it should always be attempted to place such cargo in a protected location. Cargo insurers are likely to ask for a “lashing certificate” to be issued for the transportation of expensive yachts, and Gard actually recommends members to carry out a lashing survey at the time of loading if a competent surveyor can be found. Loading and unloading As mentioned, some yachts have been seriously damaged by falling out of the forward sling during lifting. The reason for this is that the hull form goes from a flat, full width bottom aft to a sharp, narrow bow shape forward, and the fact that a yacht is likely to be heavier at the aft end due to the location of the engine. When starting to lift the boat, it may tilt backwards due to this being the heavy end, and the forward sling may then slip off the bow, and the bow of the yacht will come crashing down. Bowsprits and platforms are then likely to break off, and depending on the hull material, weight of the boat and height of the fall, the hull may be holed or the stem, keel and bow plates may be fractured. The shock of the fall on a concrete quay or a steel hatch cover will be considerable and may also result in damage to windows, furniture, lanterns and electronic equipment. The way to counteract the risk of the forward sling slipping off is to place it in the correct position, sharing the load correctly with the aft one. To do so, the position of the engine and of heavy items like full tanks should be verified and slings placed accordingly. It is also very important to put horizontal webs between the two slings, in order to keep them in place and stopping the forward one from being pulled off. Also, the lifting should of course start very carefully and guy ropes should be attached to control horizontal movements.
Photo courtesy of Bull Sworn Marine Surveyors S.L.
Repairs Footnote
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