Correct anchoring in tidal waters is vital to ensure a carefree evening for all persons on board the boat. There is nothing worse than anchoring improperly and waking up in the middle of a dark night with your boat adrift or resting on top of a reef or bommie (isolated coral head).
The guidelines and procedures for correct anchoring are as follows:
- All boats are equipped with 55m of chain and a plow anchor.
- Do not anchor where the water depth is/will be less than 4 meters at low tide or above 15 metres at high tide. The best anchoring depth is between 6-10 metres in anchorages with no coral and 10 to 15 metres in anchorages with coral.
- Always anchor in an approved anchorage as per the “100 Magic Miles” cruising guide.
- Never anchor on coral. Your ground tackle will damage the coral, the anchor will most likely get fouled and the Marine Park Authority will fine you.
- Use the chart and the cruising guide to decide exactly where to anchor, noting water depths and the position of shallow water, reef, etc.
- Always approach your intended anchoring spot against the wind or tide whichever is the strongest. (Note the direction other boats are facing and approach the anchorage in the same direction).
How to anchor
- Approach the anchorage slowly (less than 3 knots), with the dinghy in davits or tied alongside and short. Ensure that the bitter end of the dinghy painter (rope) is not in the water and that the anchor is prepared to be dropped. Have a crew member forward looking for any reef. Coral reef often appears suddenly from deep water so your depth sounder may be of little use in this situation. Isolated coral heads (bommies) may be outside the main reef line. The usual colour from above the water is yellow/brown. Reef is best seen with Polaroid sunglasses and at low tide. Try to approach so that you are not looking into the sun, as the reef may be hard to see due to the sun’s reflection on the water. If you are looking into the sun, go out again and approach from a different direction. If necessary do a circle around the spot you intend anchor in order to check the depth and possible obstructions, then approach the spot into the wind/tide. In the afternoon, from about 3-4pm, reef areas are difficult to see since the sun angle becomes too low to show the difference in colour between shallow and deep water.
- To determine the scope (amount of chain to put out) when anchoring:
- Check the depth with your depth meter, chart or lead line.
- Check the tide tables for any expected increase in depth.
- Multiply the total by 4 for the minimum length of anchor chain you should put out. For example, if the depth of water is 8 metres at low tide and the next high tide is 2 metres, the total equals 10 metres. Multiply by 4 and your minimum length of chain is 40 metres. In any event, never put out less than 35 metres of chain.
- Note the spot where you are going to drop your anchor, allowing for enough swinging room between your boat, other boats and any coral reef. Bring the boat to a complete stop at this spot. Slowly let out all of the chain you intend to drop as the boat drifts with the wind and current. Let the wind or current take the boat backwards until the chain goes taught. As a final test, run the engine or both engines very slow in reverse for 5 to 10 minutes to allow the anchor to dig in and to confirm the anchor has taken. When completed, fit the snubbing rope and let more chain out so that the all the weight is on the rope. If necessary check the depth around the boat with your lead line.
- Here are a few steps you may take to confirm that your anchor has taken:
- Check any vibration on your chain, while it is taught / while you are in reverse, by physically feeling the chain. If the chain is vibrating after it is completely stretched out, then your boat is most likely dragging anchor and you should either re-anchor your boat or let out more scope to enable your anchor to dig in properly. Sometimes the anchor can pick up a piece of coral, rock or bottom rubble and regardless of the amount of scope you let out your anchor will still drag.
- If your anchor has taken you will see little eddies coming along side your boat from the stern towards the bow. This is caused by the prop wash if you boat is sitting still and not moving back in response to the engine being in reverse.
- Once you turn off your engine you can take a bearing on a fixed object from your bow and 90 degrees from that point or from your beam. Check periodically that these two bearings maintain a 90 degree angle. It is important that you have taken the bearing on a fixed object and not a floating object that can also change position.
- A rough guide to determine if you have enough swinging room is as follows:
- Your boat should be 3 – 4 boat lengths from the position you first dropped the anchor.
- The distance from the point where you have dropped the anchor is the radius of your swing, as the boat moves around. You may move in a full circle as the tide changes, so it is important to make sure there is no shallow water, reef or bommie within the circle of your swing.
- As you swing around with the tide/wind, check the position of your boat against adjoining landmarks now and again to ensure the anchor is not dragging.
- If you are being affected by strong winds, or if you are not in a protected anchorage, let out more chain as this improves holding.
- The anchor winch uses a lot of battery power, so select your anchoring position carefully. It takes time before the engine can recharge your anchor winch battery. Dropping and pulling your anchor up twice in a short period of time, could flatten the battery. Pulling the chain up by hand is a lot of hard work.
The guidelines and procedures for raising the anchor are as follows:
- Start engine(s) and run in neutral (approx. 1200-1400 rpm) for at least 10 minutes before operating the anchor winch to raise the anchor.
- Make sure there are no ropes or fishing lines overboard and that the dinghy is tied along side and short.
- Motor very slowly forward (short bursts) along the line of the chain while the anchor is hauled aboard – use hand signals between the foredeck and the helmsman to indicate direction.
DO NOT EXPECT THE ANCHOR WINCH TO TOW THE BOAT TOWARDS THE ANCHOR.
- If the anchor appears caught (the chain does not come up easily without strain on the winch) fit the snubbing rope, take any pressure off the chain by releasing the clutch. Normally the gentle motion of the boat frees the anchor. If the anchor remains caught, motor gently forward with the snubbing rope attached and the anchor should break out. If not, let out 4m to 5m of chain and try again. If this fails call Whitsunday Escape for assistance. Do not motor around in circles as this will make the problem worse. You may need to snorkel over the chain to see what it is caught on. Free public moorings are now installed in most anchorages with coral. You are unlikely to foul the anchor provided you stick to the recommended anchorages.
- As the anchor chain comes in, check that the chain is not piling up in the anchor locker. If the chain comes in muddy, wash with buckets of water. Slippery chain is very difficult to handle, a slippery deck is a safety hazard and dried mud in the anchor locker may mean the chain jams next time you are dropping anchor.