What anchor size and chain length are suitable for a Monsun 31?

For a Hallberg-Rassy Monsun 31, I would fit a modern 15 to 16 kg anchor with 50 metres of certified 8 mm short-link anchor chain for normal coastal cruising. For mainly sheltered Danish anchorages, allow 40 to 45 metres; exposed cruising or deeper water can justify a 20 kg anchor and additional rode.

Check bow fittings and retrieval

The Monsun 31 has a published displacement of about 4.2 tonnes. A cruising boat usually weighs considerably more once loaded, so a substantial anchor makes sense. First check that the bow roller, locker and retrieval equipment can handle it.

Many Monsuns have had their anchoring gear modified over the years, so equipment varies between boats. Check these points before ordering:

• Bow roller: the anchor must sit securely without its tip touching the stem or its shank fouling the pulpit.
• Chain locker: leave enough room for the chain to fall and drain without piling up beneath the hawsepipe.
• Windlass: identify the gypsy specification. Nominal chain diameter alone does not establish compatibility.
• Deck fittings: inspect the roller mounting, cleats and backing plates for movement, corrosion and water damage.

Keep hands and feet clear of the chain. Isolate the windlass electrically before clearing a jam.

Choose the main anchor

A modern 15 to 16 kg anchor is a sensible main anchor for this boat. Examples include a 15 kg Rocna, 15 kg Spade or 16 kg Lewmar Delta, provided their dimensions suit your bow arrangement. Performance varies with seabed and design; equal weight does not guarantee equal holding.

For frequent nights in exposed anchorages, a modern 20 kg anchor gives extra margin if the roller and retrieval equipment can accommodate it. Experienced long-distance sailors often carry anchors twice the catalogue minimum or heavier. That is a conservative cruising choice, rather than a universal sizing rule.

If the boat already carries an older CQR or Bruce-pattern anchor, check its actual weight and condition before deciding to keep it. Do not automatically trust a small anchor inherited with the boat for overnight use. Carry a second anchor too, preferably with different characteristics to suit an alternative seabed.

Size chain for depth

Certified 8 mm short-link galvanised chain is a practical choice for a Monsun 31. Buy chain with declared strength and dimensional specifications, and match its exact standard and pitch to the windlass gypsy. Do not assume DIN 766 and ISO chain are interchangeable simply because both are labelled 8 mm.