Towing a GP14 Dinghy on the Water Suggestions and Ideas

Transcription

1 Towing a GP14 Dinghy on the Water Suggestions and Ideas This supplement addresses the subject of recovering a boat and crew when the boat needs towing and is specifically written for the training situation. Many of the ideas noted are also applicable when recovering a dinghy by towing from a racing situation. At least three very different scenarios are likely to arise in a training situation: 1. Towing a single GP14, either astern or alongside 2. Towing a number of dinghies simultaneously 3. Towing an empty (unmanned) dinghy, perhaps after having recovered the occupants Most of the points to be considered are not specific to the GP14, and apply equally to almost any comparable sailing dinghy in its size and weight range. One would like to be able to assume that all coxswains of safety boats are competent and reasonably experienced seamen, and able to exercise a seaman s judgment in assessing the situation as they find it. These notes may however be of help to less experienced safety boat personnel It is no part of the purpose of this manual to offer detailed advice on how a safety boat should be equipped or handled. All we will say on that account is to stress the importance of two points when towing: 1. The need to maintain steerability of the tug - So if you don t have an elevated amidships towing point it may be easiest to secure the towline to a bridle across the transom of the towing boat via a very free-running block or very large diameter ring or snap hook. 2. The importance of being able to instantly cast off the tow in emergency from the tug. If taking the towline to a bridle, be aware that it is the bridle that will need to be cast off the boat in these circumstances, as you won t be able to cast the towline off the bridle. The end absolutely MUST be able to render through the block or snap hook or ring. If it is not possible to arrange for either end of the bridle to be instantly cast off in emergency (as is the case with some RIBs) the solution may be to have a sharp serrated knife always to hand, so that in extremis the bridle can be cut. Ensure that there are no knots or backsplices in the ends of the towline, or any other obstruction that may prevent it rendering out freely if you suddenly need to cast it off in a hurry

2 So far as the GP14 itself is concerned there are three vitally important general principles: 1. The towline must be attached to the dinghy in such a way that it can be cast off at any time, even if under heavy load. The only exception to that is when towing an empty dinghy, when there is no point in being able to cast off that end, but it must still be possible to cast it off from the tug. 2. The towing force on the dinghy normally needs to be applied to either the mast or the thwart. If towing stern-first (see final section) it should be secured to the thwart rather than the mast. 3. The towline needs to be led through a fairlead, as close to the stem head as possible, even if a fairlead has to be improvised. Adapt this principle if towing stern-first; obviously the towline then needs to be centred at the transom rather than at the stem.

3 1.1 - TOWING A GP14 ALONGSIDE Bear in mind that if you are using anything more than just a single rope you won t be able to cast off quickly in an emergency. You will also have increased wave action and slop between the two boats. So this is for smooth water only, and you will need to tow only slowly. It is still important not to make ends fast, so that it remains possible to cast off even if it is not as quick a process as when using only a single line. Unless you are towing with an inflatable, ensure that you have adequate fenders in place. If the tug isn t long enough to tow with a head rope, use a forespring (leading forward from the thwart of the dinghy to a point well forward on the tug) to do most of the work. If at all possible use some form of anti-chafing gear (a sponge or cloth will do) to protect both dinghy and rope where the rope crosses the carlin and the deck edge. Towing alongside a RIB. Forespring (shown in red) provides the actual pull Rudder used to counteract tendency to turn outwards. Forward breast rope (optional, shown in blue, dotted) positively prevents dinghy swinging outwards. If you have a competent helmsman in the dinghy and he is able to steer this may be all you will need, but a forward breast rope will not only make his job easier, it is a vital safety line in case the helmsman is momentarily distracted. Without this, if the tiller is even momentarily unattended the dinghy can start to start to swing outwards. If that happens, there comes a point of no return, and thereafter the spring will come athwart the GP and it is then very likely to capsize her! The forward breast rope is the safety line that prevents that situation arising. Use the dinghy s painter, and bring it from the stemhead on the dinghy to a point roughly abeam of that on the tug. If the steering is disabled (broken or lost tiller or rudder) it may help to use an aft breast rope as well; the forward breast rope will prevent her sheering outwards, and the aft one will prevent her sheering inwards.

4 Similarly holding the two boats together by hand should not be done when towing alongside on a spring. Either hold by hand but use no ropes at all - then if the crew (up forward) loses his grip the helmsman can simply let go before any damage is done, or tow with a spring in conjunction with a forward breast rope which must be properly secured. If shorthanded and towing an empty dinghy alongside consider how you are going to stop when you reach the beach, or dock, or whatever. Depending on the circumstances you may want to rig a backspring as well, in order to stop the dinghy surging ahead.

5 1.2 - TOWING A SINGLE GP14 ASTERN As with towing alongside, moderate or slow speeds. remember that all towing should normally be done at only Pass one or more round turns of the towline round either the mast or the thwart, ideally two round turns in most situations, but DO NOT MAKE THE END FAST; instead get one of the occupants of the boat to hold the end in his hand. If the boat gets into difficulties he can then simply let go of the end and the line can be cast off. Foredeck mooring cleats. A minority of boats have such a cleat installed, but we strongly advise against securing the towline to this, because there are too many problems. The cleat may not be sufficiently strongly secured, particularly if one needs to tow faster than originally anticipated, or if the boat is waterlogged; the strain will be massively increased if you need to add other boats towing astern of the casualty; and the crew cannot cast off in an emergency without going forward - which if a waterlogged or holed boat starts to submarine is the very last place you want them! Fairleads. For boats regularly used for training it would be sensible to mount an anchor fairlead close to the stemhead for this purpose, and it is equally useful when one needs to anchor a boat. A pair of them, one each side, is neater, and also allow a pair of towlines to be set up as a bridle. What used to be known as the Swedish pattern, and I gather is now more often called a Skene cleat (which may be a U.S. term, but now appears to be gaining popularity over here) are probably the best; they have a pair of overlapping fingers, and if well designed they prevent the rope from jumping out of the fairlead when towing through waves. Standard anchor fairleads (NOT Swedish type, a.k.a. Skene cleats)

6 Swedish anchor fairleads, a.k.a. Skene Cleats. It is almost impossible for the rope to jump out accidentally. Unfortunately they are now difficult to source in sizes small enough for a dinghy; these are 4½ inches, which is perhaps tolerable, but 3 inches would be more suitable. For a training boat that does not have such fairleads a temporary substitute may be improvised by securing a large carbine hook to the forestay. This should be done before the boat is launched; it will be far more difficult on the water in a rescue situation. It should be lashed (or otherwise secured) to the forestay in some manner which can be relied on to keep its plane reasonably vertical at all times, so that if the crew in the boat need to cast off the towline they can rely on its ability to render through this improvised fairlead; if it is allowed to twist out of the vertical the rope may jam in it. Try never to get into the situation of having to improvise a means of securing the towline to the forestay while already in a rescue situation; without a fairlead of some sort it is very difficult to ensure that the towline is kept close to the forestay at all times while also ensuring that it will not jam if cast off in an emergency. And just a loop of rope is liable to twist and then jam. That is why the fairlead/s must be sorted out before launching. Centreboard and rudder. Centreboard should be raised, so that if the boat sheers she cannot trip over it (with resulting risk of capsize). If the rudder and tiller are undamaged, leave the rudder shipped and the blade down, and ensure that the GP is actively steered. Normally she should be steered in the wake of the tug, although with a long enough towline there may be some occasions when she is deliberately steered to one side of the wake. The latter may include the last few yards when coming in to a beach, especially if there is insufficient depth of water for the tug. If the steering is disabled then some degree of steering may be effected with an oar or paddle. If the boat isn t carrying any, then questions need later to be asked as to why - but so fas as the immediate emergency is concerned there is little useful purpose in leaving the occupants still aboard, unless there is a shortage of space on the safety boat. Consider transferring the occupants to the safety boat, and then tow her empty on a pair of lines; see below. Rough water. If the GP is still manned, increase the length of the towline, monitor the behaviour of the casualty, and be prepared to reduce towing speed if necessary. If the GP is empty, see below.

7 2. TOWING A STRING OF DINGHIES ASTERN All the above still applies, but you will need to consider the following additional points: 1. The tension in the tow line near the front of the string will be a lot greater than when towing only a single dinghy. 2. You don t want to put the earlier casualties in tension, with the pull of the tug applied up forward and the drag of the other casualties applied aft. This can make it impossible to steer, and in extreme cases can risk structural damage. 3. If the tow line passes the full length of the cockpit it can substantially impede the occupants of the boat, who in rough water may still need to actively balance her. This is at a time when the cockpit may be already encumbered by the boom and mainsail (or even both sails) if sail has been lowered. Possible solution: Consider towing a long heavy warp behind the tug, to which each casualty bends on its own line. Use a rolling hitch to secure this line to the main towline (make sure that your trainees have been taught how to tie this, before they go afloat!). The inboard end of the casualty s own line should then be passed around the mast or thwart as before. The casualty s painter may be used for this purpose provided it is not permanently attached to the boat, so that it can be rapidly cast off in emergency. Alternatively boats may each carry a dedicated tow line; this is quite normal practice for organised day-cruising events, and we can commend the practice for training situations. Alternatively, consider towing a long heavy warp behind the tug, to which a number of suitably spaced out individual tow lines have already been permanently secured. Each successive casualty in the string picks up the next available individual line from the main warp. However this technique imposes particular design requirements on the safety boat, and not all safety boats are suitable (see below). You won t want to start trailing this warp until you commence towing, and will then want to veer only enough of it for the actual number of casualties in tow. Therefore this cannot be clipped on to a bridle at the stern of the tug, but instead it must be turned up to a bollard; this is the only way that I can think of which will enable you to vary the length and also preserve the option to cast it off in case of emergency. Since not all safety boats have such towing bollards - and not all are reasonably capable of being fitted with them without compromising their steering - the particular safety boat will be a factor in determining whether this option is viable.

8 3. TOWING AN EMPTY GP14 Except for harbour manoeuvres in calm and sheltered water (e.g. bringing a boat in from moorings), only attempt this if there is no other option. In rough water and if the dinghy is waterlogged (perhaps following capsize) it may well be asking for trouble to attempt to tow her empty. The writer has personally seen an RNLI crew attempt this and fail, and have to cut the boat adrift as a result of repeated capsizes, and admits to being incredulous when he saw them take the single remaining crew member (who was fully functioning) on board their ILB and then attempt to tow the waterlogged GP empty. That is not to criticise the RNLI in any way; merely to illustrate the difficulties of the situation, and the very little experience that any of us - even the acknowledged rescue experts - have of towing an empty and waterlogged sailing dinghy in rough water. In extremis, if a dinghy is in trouble and you need to recover the crew ashore urgently the best option in rough water may well be to anchor the dinghy; ferry the crew ashore, and then return with assistance so that you can put a crewman on board the casualty before towing her. The crewman can then both steer and balance the boat. If the boat is empty it may be more prone to capsize, so ensure that all loose gear is tied in before you start towing. This is particularly important in rough water. Centreboard and Rudder Centreboard should be raised so that she cannot trip over it if she sheers. If you still really must tow the boat empty, the choices then come down to two primary choices, each of which may then be implemented in either of two ways: 1. Keep the rudder blade out of the water. a. Remove the rudder. Remember to tie it into the boat. b. Leave the rudder shipped, but fully raise it (so that it is clear of the water), and tie the tiller in a central position. Except in a following sea, this will achieve the same effect as a. above; if there is a heavy following sea then unship the rudder. 2. Use the rudder in lieu of a skeg. Leave it shipped, with the tiller tightly lashed in a central position. a. Leave the blade fully down b. Partially raise the blade, until just the lowest portion (the part that in normal use would be the leading edge) is still in the water We have not at this stage done any comparative tests, and don t not have sufficient documented accounts of others, so we cannot advise which of these alternatives to choose. Since even the RNLI have been seen to get it wrong we rather suspect that no-one, not even the acknowledged rescue specialists, have any answers yet - so we don t feel too bad about not having the answers ourselves. Probably the best that can be done is for the competent and experienced safety boat coxwain to use his or her seaman s judgement, in the circumstances as he finds them. However we would welcome feedback on trainers and safety boat coxwains experiences with these various techniques.

9 Tow Lines We suggest adapting standard good practice for towing a tender astern of a yacht; use a pair of lines from the stemhead of the dinghy, one to each quarter of the tug, and use as short a scope as the sea state will permit. When the dinghy starts to sheer to one side, as she most surely will, the line to the opposite quarter of the tug is at a much greater angle to the dinghy s sheer than a single towline would have been; the twin-line arrangement therefore gives far better directional control.

10 If towing in a large following sea beware of the tendency of the tow to surf down the waves and ram the stern of the tug. If the tow is manned and steered the traditional solution is to lengthen the towline sufficiently, but if towing an empty boat we suggest that you improvise a drogue to be towed astern of the casualty. If operating in an area where heavy seas are possible it might be worth carrying a suitable drogue as part of the emergency kit of a safety boat. In extremis, if no other option is available, you could use the mainsail (still on its boom) as a drogue. Towing it by the head cringle risks losing it if the cringle tears out; it is probably safer to secure the two ends of the boom by long lines to the two sides of the casualty s stern, and allow the sail to then lie flat in the water and follow astern of the boom. In either case the drogue line/s should be secured to the thwart, and then led through fairleads (which you may have to improvise) at the transom. Use the mainsheet horse or bridle (if fitted) to improvise such fairleads. Towing a drogue, to control the casualty in a following sea. Left - a purpose-designed drogue, perhaps carried as part of the kit of the safety boat Right - mainsail used as an improvised drogue. This risks damage to the sail, possibly even loss, but repairing or replacing the sail is a lot cheaper than losing the boat!

11 TOWING STERN-FIRST This is not something that most of us would normally think of doing, but it features in an account quoted in one of the books written by the world-class experts Frank and Margaret Dye. The occasion was a Wayfarer rally on the East Coast, run by Tony Newman, described as a highly experienced cruising sailor. Despite two forecasts of intially moderate winds followed by deteriorating conditions much later in the day, they were caught out when conditions deteriorated more or less immediately. Very exceptionally, with two casualties, they enlisted outside assistance in a rescue operation; part of that rescue operation used the local ferry boat, with Tony Newman aboard as well as the ferry boat skipper. The relevant part of the account, which is Tony Newman s description, reads: The scene was unforgettable: the sea was a turmoil, there was lightning, with thunder and rain, not to mention the wind, Force 8 now Having secured a heavy warp to the thwart, and led out through the transom, Sea Urchin was ignominiously towed in, stern first. We were all in the ferryboat by now, and apparently this is the only safe way to tow an empty dinghy in a seaway: towed from the bows she is likely to sheer about and capsize. (Open-Boat Cruising, 1982, pp.57-8) While we cannot comment on this from our own experience, this account comes with the very highest of credentials. Of course, it is essential to remove the rudder before attempting to tow stern-first. There are however some relevant and important points of difference between the Wayfarer and the GP14, with the result that in two respects the technique needs slight adaptation if it is to be used on GP14s. 1. With modern mainsheet arrangements specific attention will have to be paid to some effective means of keeping the warp centred as it crosses the transom. Perhaps by using the transom bridle, if the boat has a split tail mainsheet. With the 1960s-style full width horse former surmounted by a track, or with the original short horse, one can pass the warp through the horse. With a pure centre mainsheet you will need to improvise. 2. The GP14 has only a single chine, and the underbody has less rise to the transom than does the middle panel (i.e. the one between the chines) of the Wayfarer hull. Thus although in flat water the transom of an empty boat will float clear of the water, when making sternway in a big sea one should expect less lift and more slamming as waves hit the stern. Thus speed will have to be kept to a minimum, and it may help to put any convenient weight into the fore part of boat to ballast the bows down and thus lift the stern.