What is chain wrap?

How chain wrap happens

A mushroom anchor sinks into a soft bottom and gains suction over time. Its stem, though, is a vertical post. As tides, currents and wind swing a moored boat through 360°, the chain rotates around that stem.

Once the chain catches, every cycle pulls it tighter.

What chain wrap does to a mooring

How damaging chain wrap can be for your boat

Chain wrap doesn't announce itself. It shortens your scope and raises the peak loads on the whole mooring system, so every gust and every tide asks more of the chain, the shackles, the mooring ball and the boat on the other end of them.

When something gives, the boat breaks free of its mooring, and a boat adrift is at risk of damage or loss. Captain Gregory Smith spent two decades in mooring service watching chain wrap break boats, mooring fields and seasons.

Why a swivel doesn't stop it

Swivels and bridles reduce twist in the chain. A swivel lets the chain unwind itself above the swivel. Below it, on the anchor side, the stem is still a vertical post and the chain still rotates around it as the boat swings. The wrap forms where the swivel cannot reach.

That is why the fix has to be on the anchor. Read why a swivel doesn't stop chain wrap.

How MoorSafe significantly reduces the risk

Three symmetrical bars rise from the bowl to a single point above the stem, forming a cone. The chain has nothing to catch on, so it slides off as the boat swings. That removes the catch point that causes chain wrap and significantly reduces the risk of it. The bowl is the same concave mushroom bowl, so it still beds into the mud and gains suction.

In the Casco Bay field test, a diver found no chain on the MoorSafe stem after 28 days of tide. Read the field test, or see how the cone works.