advanced anchoring techniques
In the sketch on the right a yacht (LOA. 10 metres) is at anchor in 5 metres of water and the wind is strong enough for the cable to be fully stretched. The cable is marked to scale at 10 metres. The wisdom of letting out more cable in a blow can be seen by comparing the angle of the shank of the anchor above the sea bed at scope 3, scope 5 and at scope 7.The lower part of the sketch illustrates the effect of sending an angel down the cable at scope 5. Sending it two thirds of the distance towards the anchor is illustrated in red. Sending it one third of the distance is illustrated in green. In either case note the very short distance which the bow of the yacht has moved towards the anchor. In light winds the yacht should dance around the angel but when it blows hard it will eventually dance around the anchor. How hard does it need to blow? The answer to that depends on the scope deployed and the weight of your angel!
In a crowded anchorage an angel can reduce your swinging circle by deploying it closer to the bow but this will only work in light to moderate winds. In strong winds it can be deployed closer to the anchor to improve the effectiveness of your cable by keeping the anchor at a smaller angle to the sea bed. In this situation the angel needs to be really heavy to be effective and will never be any more effective than the equivelant weight of chain. So if you have chain in your locker which has not yet been deployed let it all out before you think about sending down an angel in a blow.
A heavy angel is not easy to deploy. I have experimented with different methods. In the photo I have anchor chain bound up as an improvised angel weighing 35kg. Difficult to deploy even more difficult to recover! If it’s blowing up in a crowded anchorage and you are worried about swinging circles then my advice is simple: Escape now before it’s too late!
Do Angels delight? I think the answer is only sometimes!
The Riding Sail
I had my sailmaker make me a dedicated Riding Sail which is simply hanked onto the backstay with an improvised strop on the tack to a strong point in the cockpit. The main halyard or the topping lift hoists the sail to the desired height and sheets are led forward and tensioned on a trial and error basis. The result is illustrated in the main photo.
In strong gusty winds the riding sail reduces the arc through which the stern swings by about 15 degrees but more significantly the speed at which the boat yaws is reduced. In combination with 2 anchors down in the fork moor (illustrated in the Sailing Life article) this makes Westbound Adventurer as tame as it is possible to make her.
There is a twin riding sail which I have captured on camera on a Barra fishing boat. I guess this would increase stability even further. It’s a piece of kit that would only be considered by those who plan to spend a lot of time at anchor. If you already have a storm jib which is small enough you could do your own experiments with this.
In the photo of Westbound Adventurer at the Flannan Isles a line comes from the bow through an attachment point ashore and back to the yacht for ease of departure. The engine is running slow astern and the yacht is not left unattended. NLB no longer maintain the steps and have issued warnings that they may not be safe. On another occasion I have anchored off with a heavy angel on the bottom because there is a high risk of fouling an anchor on the rocky bottom. The yacht was not left unattended on this occasion either.
When anchored close inshore in the conventional manner it is sometimes possible to take a long line ashore as a “preventer” which is secured in a slack condition and will only come under tension if the anchor drags. Many yachtsmen will rig a preventer on a swinging mooring as a back up to the well used or not yet replaced line on the mooring. If you think you have found a suitable rock ashore which will cover at high water you need to take measures to ensure that your line does not float away while in slack mode!
When we go ashore in the dinghy we can usually see what we are in for and take the appropriate precautions. Sometimes we don’t foresee the conditions on our return some hours later. When exploring remote places and uninhabited islands a useful piece of kit is the “endless” mooring line. You need a small anchor with a short length of chain connected by a line to a ring and fender. You also need a long line to run from shore through the ring and back to the shore. With everyone ashore you send the dinghy out to the anchor which you have dropped a short distance offshore. When you return at a different state of tide from your party ashore or hill walking expedition, you haul the dinghy towards the shore and jump in from your rocky ledge. If it has been a beach landing you still have to get wet but the dinghy can be held afloat while crew clamber in and start the outboard motor. This takes time to set up but reduces the fun and games pushing the dinghy into the swell from the beach as someone rows hard to get into deep enough water to start the OB. There are of course many land locked pools where it is calm enough to lift the dinghy ashore and lift back to launch. The endless mooring is for the exposed landing.
In the final article next month I challenge those who have not yet done it, to drop the anchor under sail then sail it out.
Paul McNeill is a Yachtmaster Instructor and Principal of Westbound Adventures Sailing School which operates on the Clyde and in the Scottish Hebrides during the summer months. Paul is also a member of the Royal Institute of Navigation.