{"id":138689,"date":"2022-05-31T06:42:57","date_gmt":"2022-05-31T05:42:57","guid":{"rendered":"https:\/\/www.yachtingworld.com\/?p=138689"},"modified":"2022-05-31T06:46:36","modified_gmt":"2022-05-31T05:46:36","slug":"masterclass-load-cells-strain-gauges","status":"publish","type":"post","link":"https:\/\/www.yachtingworld.com\/expert-sailing-techniques\/masterclass-load-cells-strain-gauges-138689","title":{"rendered":"Masterclass: Using load cells and strain gauges on cruising yachts"},"content":"This is Part 2 of Vicky Ellis<\/em>\u2019<\/em> guide to preparing your yacht for any eventuality. You can read Part 1 here<\/a>.<\/em>\r\n\r\nIn this series we examine some of the more likely incidents that occur on long bluewater ocean passages<\/a>, not necessarily the headline catastrophes. Here I\u2019m going to look at some of the issues that may occur with the rig, and how to keep your crew \u2013 your biggest asset \u2013 on side, happy and healthy.\r\n

Chafe is the enemy<\/strong><\/h3>\r\nLosing your rig<\/a> might be foremost in your mind, but before we get on to that, let\u2019s look at something you definitely will experience: chafe<\/a>. Chafe is one of the biggest gremlins for bluewater cruisers. Keeping chafe at bay, checking for it and protecting against it with careful design, clever ideas and some anti-chafe protection will get you through a voyage unscathed. Without this, it will eat its way through halyards, sheets, sprayhoods and more in a matter of days, if not hours.\r\n\r\nJerry Henwood (best known as \u2018Jerry the Rigger\u2019) explains that a halyard with a small amount of play will roll a tiny amount backwards and forwards on it\u2019s turning blocks with every wave and, in the course of a typical Atlantic crossing<\/a>, could therefore move the equivalent of 8km while loaded. Shifting your halyards a centimetre or two a couple of times a day will help move the wear point on sheaves and jammers and prolong life.\r\n\r\n[caption id=\"attachment_125793\" align=\"alignnone\" width=\"1200\"]\"bluewater-sailing-yacht-preparation-cockpit-credit-tor-johnson\" Photo: Tor Johnson[\/caption]\r\n\r\nIf you can\u2019t bear the sail trim that this trick produces, then take some lengths of the thin yet tough anti-chafe Dyneema sleeve. It can be secured over the top of your lines in areas of wear.\r\n\r\nThis rope chafe protection is especially good where guys go thorough pole beaks, for tack lines that may chafe on a swivel block, and reefing lines or halyards. If you can\u2019t get hold of the specially designed anti-chafe sleeve, the outer sheath of old sheets can be placed over the top of ropes. Just ensure that the edges of the outer cover are well stitched and whipped on to prevent the sleeve coming loose and jamming the line.\r\n\r\nOther tips for prolonging the life of your lines are to end-for-end them every so often or to buy them extra long and trim some off when it looks worn. Other items I squirrel away before setting off are snatch blocks, big and small \u2013 and well made. They\u2019re an expensive collecting habit, but worth it.\r\n\r\nArticle continues below...<\/em>\r\n\r\n
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\r\n\r\nPreventers that run back to the cockpit, poled-out jib sheets and downwind rigs all get in the way of something and having snatch blocks and a stash of soft shackles or Spectra strops can allow you to make an easy re-routing plan to avoid chafe in the middle of a valuable line.\r\n\r\nPoled-out headsails are the bread and butter of bluewater downwind rigs. It\u2019s a good idea to secure your pole independently of the headsail sheet using an uphaul\/topper, downhaul\/foreguy and guy\/aft guy. Running the headsail sheet through a snatch block attached to the outer end of the pole reduces chafe in the beak and means you can furl the sail quickly if a squall crops up, without worrying about moving the pole.\r\n\r\nTo avoid the clanging sound of a snatch block hitting your pole, add a wrap of thick leather or rope around the end of the pole to absorb the clangs.\r\n\r\n[caption id=\"attachment_125792\" align=\"alignright\" width=\"320\"]\"bluewater-sailing-yacht-preparation-chafe\" Sacrificial sleeves of Dyneema or old line sheaths will help protect against chafe in areas of high wear[\/caption]\r\n\r\nChafe also affects canvas and sails; it\u2019ll not take long to wear a hole if a mainsheet is rubbing on a bimini or sprayhood. I do chafe checks after every new sail set-up and on the whole boat twice a day at sea. I like to do a dawn and dusk check and get the rest of the crew involved, so that it\u2019s not a case of one pair of eyes looking for the problem or knowing what to spot.\r\n\r\nMeanwhile, UV will degrade canvas covers, sails and plastic fittings (especially plastic jackstay buckles), craze hatches and degrade vanish. Keep a look out for its effect, as frustrating failures can occur as a result.\r\n

Rig checks<\/strong><\/h3>\r\nNot only does a full rig check need to be done before setting off on passage, it needs to be done regularly at sea too. A good pair of binoculars is a great help if going aloft is difficult, and perhaps one day it\u2019ll be commonplace to put drones to this use. Capturing your rig in detail on camera is a great way to confirm any changes.\r\n\r\nWhen it comes to learning about your rig and what to look for during a rig check, working alongside a professional is hugely informative, confidence-inspiring and something I\u2019d definitely recommend. You can also develop a checklist with them for your rig.\r\n\r\nStart at the top of the rig and work your way down, then go on deck from bow to stern. Choose good weather and good light. A good bosun\u2019s chair<\/a> or harness will keep you comfy for longer, enabling you to take a really good look. Use all your senses: look and feel particularly, and take off and replace all coverings. Clean rust away with a squirt of WD40 or similar and take a magnifying glass \u2013 a really handy tool to take up. Just make sure your tools are securely attached to you while aloft.\r\n\r\n[caption id=\"attachment_125795\" align=\"alignnone\" width=\"1200\"]\"bluewater-sailing-yacht-preparation-downwind-sailing\" Enjoying the long days of downwind sailing. Note the preventer led from the boom end to the bow and back to the cockpit[\/caption]\r\n\r\nIn general you\u2019re looking for signs of wear and tear, the beginnings of cracks, things missing, loose or broken, and wire\/rod problems. At the masthead, check everything you have up there such as lights, aerials, etc. Check the stays and shrouds where they join the mast, paying attention to cracks in tangs or lugs, weld cracks and problems around the swaged end fittings on the mast.\r\n\r\nWhere wire rigging enters the swaging is where it\u2019s most susceptible to damage from stress concentrations and fatigue, which will cause the wires to de-strand, break off or become distorted. Use your fingers to feel up against the swaging terminus for sharp edges and your eyes to see bulging or breaks.\r\n\r\nSlacken off the running rigging and lift up the halyards to check the sheaves are rotating freely, haven\u2019t worn a groove or become cracked. Left unchecked, this can quickly progress to a case of a jammed halyard which, if the sail is up, is a very an unwelcome problem at sea.\r\n\r\nSpreaders have a tough job and are subject to pumping forces and loads in all directions, and as such are susceptible to fatigue failures too. Their alignment and angles need to be checked as they can change. It\u2019s not uncommon to find problems at their mast joints. Inspect the cap shroud where it passes against the spreader end for signs of movement, wear or damage. Feel the edges of the spreader. If rough and your sail will rest against it, consider some padded chafe protection.\r\n\r\nSpreader end cap covers are great if your main will rest here downwind (or your spinnaker might!) but do make sure they\u2019re easily removable for checks and, as with all protective coverings, ensure they don\u2019t trap moisture. On your way down, feel in the mast track\/furler and spinnaker pole track for sharp edges, loose rivets or other problems. Check your radar (and reflector) brackets.\r\n\r\nAt deck level, check each of your rig connection points and chainplates. Wire rig swaged terminals need checking, particularly as these upwards-facing terminals are more susceptible and, in particular, check for articulation issues. Bottlescrews can become bent and the threads damaged but you can only tell this when you slacken the rig off and undo them.\r\n\r\n\r\n

Rig failures<\/strong><\/h2>\r\nAs for what to do if you get a rig problem at sea, using halyards to steady the rig in place of a broken stay can be effective. Shrouds are trickier beasts to replicate due to their less direct loading. Putting the damaged part of the rig under the lowest load is key, so keep damaged shroud\/spreaders on the leeward side.\r\n\r\nReducing and removing sail is essential to reduce rig loads, but remember that halyards and sheets will also be supporting the rig and loading\/unloading it, so think quickly but carefully here before dropping sail. The wave motion on the boat will also contribute to the dynamic loading, so heaving to may help.\r\n\r\nIf it looks like the rig will come down, make sure the deck is clear of unnecessary people and consider what next steps you are likely to need. While the VHF masthead antenna is up consider making a DSC radio call to see if help is out there just over the horizon.\r\n\r\n[caption id=\"attachment_125797\" align=\"alignnone\" width=\"1200\"]\"bluewater-sailing-yacht-preparation-lykke-dismasted\" Being prepared for all incidents, including a dismasting, will make it easier to cope if it happens[\/caption]\r\n\r\nOnce a mast has come down, whether you can salvage any of the rig will depend entirely on the circumstances and conditions. To cut it free, release the lines not under load first. Knocking pins may be easier than sawing through the rod\/wire. Running rigging or textile rigging can be unlashed or cut through with a good knife.\r\n\r\nIf you\u2019re unlucky enough to be dismasted, it may happen at night, after you have come off night watch and are tired, perhaps in bad weather with some crew sick... I\u2019m painting the worst case scenario here, but your crew can be assets if you\u2019ve planned ahead and they know how to use the rig cutting equipment, can keep themselves safe (clipping on as the boat\u2019s motion will be horrible) and have proper eye protection if cutting.\r\n\r\nOnce the rig has all gone (remember lines may have fouled your keel and propeller) take some time to take stock and regroup. Continuing the voyage is going to be possible because you\u2019ve already taken enough diesel, tins of food and there is plenty of time for you and the crew to make a jury rig (maybe that boat over the horizon can lend you another spinnaker pole). Planning alone will give your crew a sense of mission and purpose, and keep them occupied and upbeat.\r\n\r\n[caption id=\"attachment_125796\" align=\"alignnone\" width=\"1200\"]\"bluewater-sailing-yacht-preparation-lykke-dismasted-jury-rig-arc-2017\" The Hallberg-Rassy 46 Lykke<\/em> dismasted during the 2017 ARC, but the well-prepared crew set a jury rig[\/caption]\r\n

Preparing your crew<\/strong><\/h3>\r\nThere\u2019s an old adage that the sailing is the easy part, it\u2019s the crew that can be the bigger challenge. Personally I never sail without company; it makes a voyage for me.\r\n\r\nWhether you\u2019re sailing double-handed<\/a> with a lifelong partner or with a group of new friends, a harmonious crew<\/a> is a top priority. The topic of building highly functioning teams is my business these days and my two top tips in advance of setting off is to ensure you\u2019ve set the expectations of your crew right, both their expectations of the voyage and your expectations of them. Understand their motivations for going on the voyage with you \u2013 their real ones, which are probably not what they tell you first!\r\n\r\nI always find it helpful to divide up all the shore and onboard jobs among the crew, not just the watch and domestic rotas but by putting crew in charge of tasks such as rig checks, watermaking or navigation. I\u2019ve found it\u2019s often crewmembers who don\u2019t take a role who withdraw or make trouble. A great onboard role to assign, officially or otherwise, is a social secretary to ensure there\u2019s a healthy supply of halfway parties, games and fun.\r\n\r\n[caption id=\"attachment_125791\" align=\"alignnone\" width=\"1200\"]\"bluewater-sailing-yacht-preparation-celebrating-on-board\" Ensure plenty of socialising, parties and entertainment on an ocean crossing[\/caption]\r\n\r\nSetting the right culture on board the boat is crucial too. A crewmember who is thinking about safety in the same light as you is an asset. If you came on deck with the crotch straps of your lifejacket<\/a> accidentally trailing, would your fellow crew notice and, if so, would they tell you? Do talk to them openly about the plans for emergencies, get them hands on with safety kit and practice key drills regularly.\r\n

Medical matters<\/strong><\/h3>\r\nAs skipper, you need to take care of the crew and yourself too. It\u2019s vital to know every crewmember\u2019s medical history and what problems it may cause at sea. Crew who become sea sick<\/a> and are not taking or who run out of medication can lead to serious problems.\r\n\r\nA good rapport with your crew before departure will help you to acquire their medical history and current medication. But there are still many reasons why someone may not want to disclose everything. On some trips I\u2019ve asked the crew to fill in an additional medical form, which they seal in an envelope, only to be opened in an emergency at sea.\r\n\r\nPreparing your medical knowledge, skills and onboard kit and medicines in advance of the voyage is essential as you may need to be able to treat any type of injury, illness or infection. Reported medical incidents during last year\u2019s ARC<\/a> transatlantic rally included an open leg fracture, a suspected heart attack, an injured back, a case of tonsillitis and a fractured arm and rib from a gybe.\r\n\r\nShort of taking a medic with you, you can acquire the skills needed. Choose something more advanced than the basic first aid courses, preferably a week or even two of training. Some companies offer training, medical supplies and can give onboard medical advice over the sat phone\/email, although remember that emergency radio medical advice is also available from the Maritime Rescue Co-ordination Centres.\r\n\r\n[caption id=\"attachment_125794\" align=\"alignnone\" width=\"1200\"]\"bluewater-sailing-yacht-preparation-crew-credit-tor-johnson\" Photo: Tor Johnson[\/caption]\r\n

Rest and resolve<\/strong><\/h3>\r\nWe can\u2019t predict everything that could happen at sea. What you do in the heat of the moment counts but, more importantly, what you do afterwards often defines the outcome. Most disasters arise from a sequence of events. Sometimes things get worse before they get better and the first thing you try as a fix might not work. But failure means you are getting somewhere and it\u2019s good to have your expectations that way around.\r\n\r\nAbove all, when you\u2019re miles from anyone and anywhere, your resilience is what will get you through and help you find a way. Rest and resilience are proportionally linked. Factor some sleep time when trying to find a solution to a problem.\r\n\r\nIf your crew are feeling the effects of dealing with the emergency too, make sure you keep them involved, rested and informed so they can be an asset. Without rest and support, people can lose hope and give up. A crew\u2019s mood is to a great degree linked to the skipper\u2019s mood. So if you want to brighten them up, start with yourself. But when we have to find a way, we usually do. That\u2019s what makes an ocean sailor, after all.\r\n

Common problems<\/strong><\/h3>\r\nGuardwires\/missing spilt rings:<\/strong> Check each end of the guardwires and lightly silicone tape your split rings\/pins, ensuring there is space for moisture to drain out. Interestingly, half of the boats I inspected during safety checks on last year\u2019s ARC rally had a problem or missing ring\/pin from the starboard side top guardrail pulpit fitting. Damaged (twisted) wires should be replaced. Check the nuts are done up tightly on the pelican clips on gates.\r\n\r\nGooseneck damage:<\/strong> Watch for split, broken or missing washers, bolts missing and cracked tangs and components. Mouse all shackles on the boom\/vang\/sheet fittings. Check these on passage as gybes or squalls can put huge strains on gooseneck and vang fittings. A good boom preventer system is your primary defence here. Design one that is as strong as the mainsheet, goes from the boom end forward to the bow and returns to the cockpit for control. Any turning blocks along its path need to be strong enough to carry a gybe load. A boom brake is also an option.\r\n\r\nJackstays:<\/strong> Padeyes should be through-bolted with a plate and designed for purpose. Where shackles rather than lashings are used, ensure that they are moused.\r\n\r\n\"bluewater-sailing-yacht-preparation-bolt-cutters-credit-alamy\"Spares:<\/strong> What should you take with you to make repairs? Short of carrying a spare set of rigging (which, depending on your bluewater plans might not be totally out of the question), consider taking an emergency repair kit<\/a> consisting of a length of spare rigging wire and lots of bulldog clamps. Splice the wire over the problem area using alternately orientated clamps. Sta-Lok\u2019s swageless repair terminals can also be used to create a new terminal once the swaging and broken strands are cut off.\r\n\r\nA good set of spares for wire\/rod rig needed for an oceancrossing might include:\r\n