Aground: Just cruising by Keith Fleming

The ultimate grounding of your yacht is to hit the hard stuff - the 'bricks' or the rocks.

Fortunately most groundings often occur on soft hazards, like sand or mud. I think all full time cruisers at some stage of their life will hit the bottom. Avoidance is the best policy and the secret of successful cruising is in the navigation; to know where you are at all times and to be where you expect to be We usually either hit the bottom when we are moving or when at anchor, and I must admit that I have hit the bottom a few times but never laid my boat on its side. But I have seen a lot of boats on their side and some of them did not come back up when the tide came in. When moving, either sailing or motoring, you need to be aware of your surroundings at all times. Be able to read the water, your navigation chart, your tide chart, marine publications on silting and in particular your GPS cross track error. Good navigation is the key to keeping out of shallow water. Be sensible ? the hours of darkness are not a good time to be cruising in shallow water. In fact night is not a good time to be moving in any water including around reefs, except when crossing deep oceans. (Just ask Captain Cook!) When moving around reefs you have to take into account less obvious things like chart datum errors - maybe overseas the charts are not as accurate as local versions.

I recall once when we were in the Louisiades passing Bramble Cay we found the edge of the reef was out about 250m from where it should have been. Luckily it was daylight and we could see it. Another trap that can cause you to go aground is the fact that navigation markers are rarely on the edge of deep water. When travelling north to Cape York many of the lights have been placed on the reefs some 50m or 75m from deep water and if you are navigating at night time it is hard to judge how far away you are from the actual light. It is a good idea to insert a waypoint in the deep water, level with the light. Another place is the main channel at Cairns. The deep water does not go up to the marker poles; you need to stand off about 50m to be safe from grounding.

Most groundings take place at anchor. This can be caused by a number of causes, like a change of tide or change of wind moving the yacht into shallow water and then combined with an outgoing tide you find yourself with a bit of a lean. You may not actually go aground but hit the reef with the side of the hull when anchored behind it. The seabed usually drops off quite quickly around reefs and as we need to usually anchor in less than 15m of water there is not a lot of room to actually place the anchor. This takes in the considerations of the tidal flow, wind strength, amount of anchor chain required to be safe, your swinging circle, and the possibility of a change of wind direction putting you on a lee shore. If you are leaving the boat to go snorkelling, fishing or reef walking then you need to be aware of these things. The anchoring bible is your tide book of the area in which you are sailing or going to anchor. Most skippers get into trouble with grounding through failure to read and understand the tide book. Often you anchor for at least about 14 hours and you will go through two tide changes in that time and one of the low tides may be lower than the other. Always look ahead at the next tide to see if it will lower and put you aground. One skill you need is the ability to work out how much water you are going to lose from the time you anchor to the suggested time of your departure. There is a simple formula for this in the tide book. If you are chartering a yacht then know the position of the sounder transducer and whether the sounder has been calibrated to show the depth from the bottom of the keel or transducer. Also, make sure that the anchor chain is marked every 10m so you will know that you have sufficient chain out. Many a charter yacht skipper has woken in the morning to a grounded yacht that has dragged during the night.

Some areas on the east coast that are renowned for groundings are the Narrows just north of Gladstone, the Whitsunday?s, and the area between Yeppoon and Percy Island where you strong tides can sweep you into shallow water. When travelling through shallow areas always try to move on a rising tide. If you do then happen to take the bottom it should not be long before you lift off. Going aground on a falling tide is real nightmare. Especially in areas of big tides where the water seems to disappear from under your boat in a flash.

Should you go aground remember that generally the only way out is way you went in. Do not attempt to drive the boat any further forward. If you have a falling tide then immediately get the crew to the stern of the boat and put the motor in full reverse. If you have been motoring or sailing with the boat upright then you will have a good chance of getting off if you are quick enough. Getting the weight of the crew to the back of the boat lifts up the front of the keel to take the weight off. If the boat does not come off straight away then try twisting it off by moving the rudder from one side to other at 10second intervals to try and break free. Rocking the boat from side to side is another possibility. If you are travelling in company with another yacht then give them a tow line and get them to tow you out backwards. If there is a power boat nearby then see if they will help by attaching a spare sheet rope to the spinnaker halyard and getting them to pull the mast sideways to tilt the yacht on its side and so lift the keel and you can reverse easily out. This method is by far the best for getting the yacht off the bricks. If you are towing a good dinghy with a motor of around 10hp you may be able to deploy this to do the same job. If you have been sailing when you go aground then it is best to drop all sails immediately to stop the boat being driven further on the bottom. Setting a spare anchor out from the stern on a long rope may help if you are quick enough. Remember that on an ebb tide speed is essential - all the time the water is disappearing from under the boat and it is getting harder to shift. If you deploy a stern anchor you may want to set it at an angle to the boat so you are pulling the stern slightly sideways to get you unstuck. You attach this anchor rope to your main winches. While this is going on keep the motor going in reverse all the time until you realise it is hopeless.

Damage limitation
If the situation appears hopeless then look to the next step. Get out the tide book and see how much further the water is going down before low tide. If you go aground at high tide then check your next high tide to see if it is higher than the one on which you went aground. Is the boat going to lay on its side? Are there any rocks on which it may rest and you can get a mattress between the rock and the hull? If it lays right over did any water enter the boat through any of the drains or the toilet. You need to know that the hull is watertight before the tide starts to rise. If you dry out completely you may have time to scrub part of the hull while you are waiting. If you know you are going to lay over you may think to have a hot meal before it does and fill a thermos for a hot coffee because you will be there for awhile. There is not much point in deploying the main anchor unless you have an onshore breeze that will keep pushing you further on as the tide lifts you. If this looks likely then deploy the stern anchor. If you are aground amongst reef then you may consider tying the boat to the reef to help. You must keep water out of the boat at all times. If you have a side exhaust you may need to plug it before the boat lays over to stop it flooding back into the engine.

But as I said at the beginning, the secret of not going aground is in good navigation, knowing exactly where you are at all times, and thinking ahead.