Digging in for a Blow

Anchored snugly in a Hebridean HideawayAnchoring in strong winds

By Paul McNeill

To fully explore the delights of the Scottish Hebrides we need the confidence to anchor in gale force winds. The good news is that summer gales are usually well forecast and short lived. Your first experience of gale force winds at anchor will cause you some anxiety. It is only by doing it for real that you loose your natural anxiety and gain confidence in your ground tackle.

If you are cruising the Inner Hebrides you don’t have to retreat to Tobermory just because it’s going to blow up for one night. You could retreat to Arisaig or elsewhere and find all the swinging moorings occupied so it makes sense to be prepared for anchoring in a blow.

Westbound Adventurer is often at anchor in winds of over 30 knots and every summer in recent years has had 3 or 4 nights with winds over 40 knots and maximum gusts up to 60 knots. I have asked 2 cruising couples about their experiences at anchor in the Scottish Hebrides because they have more miles under their keel than I have.

Norman's rockNorman and Gillian Smith have over 40 years quality experience but cannot identify a particular month as having typically settled or unsettled weather. They are prepared for strong winds at any time. In a good sheltered anchorage they regard 40 knots of wind as only a problem for getting ashore in the dinghy. Their maximum gusts have been 74 knots in Loch Seaforth in June 2000 and 70 knots in Loch Skipport in June 2002. They reminded me that the only dependable factor is the amount of daylight and a gale during the day is never going to be as worrying as a gale in darkness. They have a particular interest in the west coast of Lewis and Harris and found something interesting in an obscure anchorage near Brenish. See attached photo!

John and Helen Anderson have been cruising the Scottish Hebrides in summer and winter for many years and have captured some fabulous images, some of which can be seen in the Clyde Cruising Club’s Sailing Directions for the Mull of Kintyre to Ardnamurchan. To mark their centenary year the CCC have a new publication, “Cruising Scotland” available in June which features many more of John’s images. John tells me that in 2000 he was lying to a single Delta anchor in Northbay, Barra. The weather was wild, with the surface of the sea being whipped off and their handheld anemometer was off scale at the top of force 9. When the wind eased, John checked at the nearby weather station at Barra airport. It had recorded the highest hourly average as 54 knots, with gusts up to 83 knots. John says that this suggests the Delta is an excellent anchor and that the holding in Northbay is superb. He has since moved to Spade anchors that he believes are even better.

Both couples agree with me that the most important issue is to head for shelter in relation to the forecast wind direction. It’s less stressful if you can arrive at your chosen location before it blows up. For cruising Scottish waters we are blessed with 2 excellent sets of Sailing Directions. Those by Martin Lawrence are published by Imray. Various people have contributed to those published by the Clyde Cruising Club. The current editor is Edward Mason. Many cruising yachtsmen keep both sets on board.

For much of the time one anchor well dug in is sufficient but how hard do we have to dig it in to replicate the full force of the winds that are forecast to hit us in a few hours time? If you are uncertain about whether your anchor is going to hold or drag you will have a stressful night. At best you will have lost sleep and at worst you might have a dangerous nocturnal battle with a dragging anchor at the height of the gale.

Anchorwatch load cell

As a sailing instructor I cannot afford to loose sleep as I will not function properly the following day if there has been an epic the previous night. Some years ago I invested in an instrument which measures tension on the anchor cable “Anchorwatch” and over a period of time I built up a profile of Westbound Adventurer at anchor in different wind strengths and also tested the strain of the cable when running the engine astern at various revs. Anchorwatch records the peak load as well as the current load and my masthead wind instrument does the same. This meant that it was not necessary to stay awake all night in the interest of science! The photos and results are self explanatory but valid only for Westbound Adventurer.

Anchorwatch control boxWhen anchoring for a blow I use the maximum scope possible with a cable of chain and warp and very gradually build up the revs astern on the engine. I know that full revs astern is about the equivalent of a F8 wind with gusts up to F9. This is only valid in a sheltered anchorage where pitching is not an issue. If I am anchoring in a familiar spot I sleep. If it’s an unfamiliar spot I could test the hold up to the equivalent of a F10 gusting 11 by motoring forward until there is slack on the cable then going astern to produce a jerk stop when the cable comes up tight.

If the anchor is not holding now is the time to select another spot and do it all over again. It may be time consuming but better now than in the dark in the early hours at the height of the gale. If after several attempts with a single anchor at maximum scope I am not confident about the holding I would put a second anchor and cable down. If any doubts still remain with 2 anchors down I would consider setting an echo sounder alarm if the shape of the seabed allows. A GPS radius alarm could also be used depending on the size of the anchorage. The last thing I want to do is to organise anchor watches by the crew in the cockpit but as a last resort it is better to do that and be ready to clear out and ride out the gale at sea rather than drag onto rocks.

Graph showing forces involved in digging the anchor inThe above is a suggested sequence of events if you need to be prepared for the worst case scenario. In practise I often put a second anchor down for training purposes even though I know a single anchor will hold. There are 3 possible techniques which I have used but I would be interested to hear from any yachtsman who has used another method.

In all cases the first anchor needs to be as well dug in as possible on a cable of chain and warp at maximum scope. It is very useful to put a marker buoy on the crown of the first anchor so that you have a reference point for dropping the second.

 

  • If you are in the chosen anchorage before it blows up the dinghy can be used to drop the second anchor and it is a lot easier if there are 2 people in the dinghy. The hardware needs to be organised on the floor of the dinghy with the anchor on top ready to drop, the chain next so that it can be paid out as you drift downwind, and the warp last so that it can be taken back to the yacht when the hardware is on the bottom. It is also very useful to have a marker buoy attached to the crown of the second anchor.
  • A second technique is to fall back on the full scope of the first cable or possibly add an extra warp to this cable as a temporary measure. With the second anchor and cable prepared on deck motor towards the chosen spot to drop the second anchor (with a marker buoy attached to its crown) and fall back on the second cable. While this is being done someone needs to keep an eye on the first cable in case it snags on the yacht. The bitter end of the (extended) first cable could come into the cockpit and be taken in and fed out as required while the second anchor is being deployed. Obviously good communication all round is important.
  • 2 anchors in the fork moorA third technique is to buoy and dump the bitter end of the first cable then motor towards the chosen spot to drop the second anchor and cable and dig it in as if it were a single cable. Using an extended warp (if required) motor over to the bitter end of the first cable and collect it.

Whatever technique is used both cables need to be adjusted by trial and error until the yacht is lying equidistant between the 2 anchors as illustrated in the sketch. This is best achieved with 2 people on the foredeck adjusting the warp of each cable led through the port and starboard fairlead rather than both through the bow roller.

Lying to 2 anchors in the “Fork moor” as illustrated in the sketch reduces the distance the yacht will yaw or swing from side to side compared with lying to a single anchor. After much trial and error I now recover 2 anchors separately by buoying and dumping the bitter end of one cable but don’t loose sight of the cable you have dumped! I am reluctant to deploy 2 anchors if the wind is forecast to shift as it can take some time to untangle the cables next morning.

Some experienced yachtsmen favour attaching a second anchor to the first on a single cable. Some believe this is a good practice only if there is a length of chain between the crown of the inboard anchor and the shank of the outboard anchor. Some experienced yachtsmen believe the practise of tandem anchors on one cable is very dangerous. The jury is out but I don’t know if a verdict will ever be reached. Research needs to be done on the merits and demerits of tandem anchors but I have so far failed to convince the authorities that there is a need for money to be spent on researching this topic. To date I am aware of only one MAIB accident report following a mishap to a yacht with tandem anchors on one cable. I would be very interested to hear from any yachtsman with good or bad experiences with tandem anchors.

If you are shorthanded and the process of setting a second anchor is daunting there is the possibility of taking a line ashore as a back up to a single anchor. The success of this is dependent upon:

  • Being able to anchor close inshore
     
  • Having a warp of sufficient length and suitable hardware for an attachment ashore
     
  • Arriving in the anchorage while conditions are safe to go ashore and return to the yacht.

What about beefing up a single cable by sending an angel down? I think I shall leave that one till next month as the issues are complex. I shall also look at riding sails, and take a closer look at shorelines.

You are probably not going to sleep well during your first night at anchor in gale force winds because the noise and vibrations on the boat can take a bit of getting used to. The boat can surge back in strong gusts particularly if you get a violent downdraft from a nearby mountain. The second and third time you anchor in gale force winds you will be much more confident about the holding power of your own ground tackle. Ear plugs are useful. Sleep well!

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.