COOMERA, QUEENSLAND – Successfully anchoring your Riviera motor yacht is one of the most important boat-handling skills you can acquire.
The demand for knowledge of this skill by our owners was reflected recently when the Riviera Festival workshops on anchoring and anchors were consistently among the most popular.
If you can set your anchor correctly and with confidence, you can rest in comfort and will not need to rely on moorings and marinas when cruising.
A well-set anchor also means that you can leave your boat at anchor and go ashore, safe in the knowledge that the anchor will not drag.
If you do not know how to anchor correctly, you risk endangering your motor yacht and others who might be anchored nearby. Equally, if your anchor is unsuitable for the type of seabed beneath your keel, there is a high chance of the anchor dragging.
Anchors and chain weigh considerable amounts, so loading up with excessive amounts of chain and anchors can affect your vessel’s performance and will only be necessary if you are planning an extended voyage along a variety of potentially exposed stretches of coastline.
Fortunately for Riviera and Belize owners, the hard work has already been done by our team of engineers. Each new Riviera is fitted with the most appropriate anchor and size and length of chain when it leaves our facility.
How an anchor works
Your anchor is only a part of the process in successfully securing your motor yacht. The anchor lies flat on the sea bed and it needs a length of chain also to lie flat on the sea bed so that the vessel’s pull on the chain is parallel. Horizontal pressure is likely to make it dig in further, not drag. If the chain lifts at an angle from the anchor toward the bow of the motor yacht, the anchor will break out from the sea bed as soon as any pressure is applied – such as a gust of wind or the effect of the tide against the wind – and will drag. The weight and length of chain prevents this from happening, provided there is sufficient length.
With sufficient length on the sea floor, the chain should then rise to meet the yacht at an angle of about 45 degrees.
Setting your anchor
The amount, or scope, of chain depends on the depth of water beneath the keel as well as tide and weather. If you anchor in calm conditions with little or no tide, the absolute minimum scope for chain is considered to be three-to-one; that is, the length of chain you release must be three times the depth of water under your keel. This is suitable only if you are stopping, say, for lunch or a spot of fishing. For overnight anchoring in a protected bay, a ratio of 5:1 is generally acceptable and in worsening conditions you should let out on a ratio of 8:1.
An old skipper was asked by a novice how much chain he should release. The old sea dog replied: “All of it.”
In tidal areas, you must also consider the changes and adjust the length of chain appropriately. For example, if you anchor at low tide in five metres of water, you would normally play out 25 metres of chain. However, if you intend to stay any length of time, you will need to calculate based on the high tide ratio. If high tide is two metres above low, you will need to release 35 metres of chain and take into account the potential for your motor yacht to swing around at anchor. Stay well away from the shore and other yachts.
Having calculated the amount of chain to release, approach your intended anchorage against the wind or current and drop your anchor slowly where you want it, playing out chain until the anchor hits the bottom. Let the boat gently drift backward as you play out more chain. This process is important to prevent excess chain falling onto the anchor and fouling it.
When you have about half of your chain out, stop feeding it out and let the boat drift and pull on the anchor. It will start digging in and will slow or stop the boat. When you feel this happening, let out more chain until all the chain length you require is out. You should now be safely at anchor.
Check for drift. If you are not secured, start again.
There are several ways of check if you are drifting. Your Riviera chart plotter may have an anchor watch feature that will let you know if you drift beyond the expected swing circle. You can also check your plotter to see if you are moving downwind or down current.
At any time the pull on your anchor changes because you are swinging around with wind or tide changes, ensure your anchor is holding.
Finally, remember at night to turn your anchor light on.
Lifting your anchor
When you are ready to leave, motor slowly forward toward your anchor, bringing chain in slowly until you are directly over the anchor on the sea bed. It should lift easily.
If your anchor does not come up, motor upwind beyond the anchor and pull. This reverses the angle on the anchor and usually helps to free it.