Anchoring to Yachtmaster standard in Australian anchorages

Anchoring is a Yachtmaster exercise because it is a decision, not a manoeuvre. Where to anchor, how much chain, whether the boat will still be afloat and still be there at 3 am: those are the questions, and the examiner listens for them before the anchor goes over the bow.

Choosing the spot

Shelter from the forecast wind and any swell, now and after the expected change. Holding ground (sand and mud hold; weed, rock and coral do not). Depth enough to float at low water with margin, shallow enough to lay adequate scope. Swinging room clear of other boats, moorings, the shore and any bank that dries. Away from the fairway and any cables. Examiners ask candidates to explain the choice before they anchor and often to identify what would make them move.

The calculation

1. Depth now, from the sounder (corrected for the transducer offset).
2. Height of tide now and at the highest point during the stay, from the tables.
3. Maximum depth = depth now + (height at highest tide minus height now).
4. Add the height of the bow roller above the water.
5. Multiply by the scope factor: 4:1 for all chain in settled conditions, 5:1 or 6:1 in fresh wind, more with rope rode.
6. Check the minimum depth at low water: depth now minus (height now minus height at lowest tide) must exceed draught plus margin.

Say it out loud: "Six metres now, tide rises another metre and a half, roller a metre, so eight and a half; four to one is 34 metres, I will lay 40 because 20 knots is forecast." That sentence passes the exercise.

Under power

Approach into the wind or tide (whichever is stronger), stop the boat over the chosen spot, lower (not drop) the anchor as the boat begins to fall back, pay out chain steadily as she drifts astern so that it lays out rather than piling, snub it at the required scope, then put the engine astern gently to set the anchor and confirm with a transit or the plotter that you are not dragging. Mark the chain so you know what you have laid.

Under sail

Approach on a close reach or close-hauled, luff head to wind over the spot with the sails eased so the boat stops, lower the anchor as she gathers sternway, and back the mainsail or use a backed jib to help her fall back and set the anchor. It is the exercise that shows whether a candidate can put the boat where they want without an engine, and examiners ask for it whenever the wind allows.

After anchoring

Take a transit or two, note the GPS position, set the anchor alarm, decide on an anchor watch if the forecast is doubtful, hoist the anchor ball by day and show the anchor light at night. Know how you would get the anchor up in a hurry (a trip line in foul ground; buoy and slip the chain if the windlass fails).

Australian specifics

• Coral. The Great Barrier Reef, the Abrolhos and the northern islands are coral. Anchor in sand patches, not on coral, both for holding and for the reef. Use the public moorings provided in marine parks where they exist; many reef anchorages have anchoring restrictions.
• Big tides. A Whitsunday anchorage with 4 m of range or a Kimberley one with 10 m makes the calculation above the difference between floating and lying on your side at dawn. In the north, allow for streams that reverse and swing the boat through 180 degrees.
• Bullets. High islands (the Whitsundays, Tasmania's channel, the Derwent) throw violent gusts down their lee slopes. Lay more scope than the wind at sea level suggests.
• Weed. Southern bays (Port Phillip, Gulf St Vincent, Cockburn Sound) have heavy weed in places; find the sand or expect to drag.
• Wildlife. Nobody clears a fouled anchor by diving in tropical Queensland, the Territory or the Kimberley. Plan to slip and buoy the chain instead.
• Sea breezes. An anchorage sheltered at 10 am can be a lee shore at 3 pm on every Australian coast. Choose for the afternoon.