Multihull anchoring

Brush up on your multihull sailing skills before heading off on a holiday charter with Gavin Le Sueur's guide to anchoring

Anchoring a multihull with success requires choosing the correct location, having the right anchor for the boat size and bottom conditions, setting the correct chain and rode arrangements and ensuring you bury the anchor effectively.

There is no anchor that covers all bottom conditions. Most multihulls should carry two anchors of different types. The classic brands come with recommended weights for yacht length-but also consider how much windage your multihull makes. Don't underestimate the required anchor weight because your multi-hull is lighter than a monohull of equivalent length.

Multihulls put a different load on anchors as they sail on the mooring line.

Windage is important when selecting the anchor size. Some multihulls are aerodynamic and low windage. Others have a profile with flat surfaces that create high windage.

In most situations, multihulls need about one size bigger than for an equivalent-sized monohull. In the traditional anchors, this equates to a heavier anchor.

Anchor selection

The features of each anchor type are found in most general seamanship books. Anchors that will readily reset themselves are an advantage if current and wind directions are variable.

Racing multihulls in specific locations can utilise lightweight anchors. Cruisers anchoring in variable locations and conditions will need a heavier anchor.

Carrying a second anchor of a style that can be set via the dinghy is useful if you have to kedge off the bottom or set up a system to avoid wide swings.

For secure anchoring, your yacht should point into the wind and be as directionally stable as possible. Use the longest practical scope-usually a minimum of 5:1 rode length to height from forward beam to the bottom (at high tide). You want the chain to pull horizontally and not lift the anchor.