Deadweight Anchor

A deadweight anchor is a mooring anchor that holds primarily by mass and seabed friction rather than by flukes digging in. It is typically a concrete block, cast-iron weight, or purpose-made sinker connected to chain or rope, used to secure mooring buoys, pontoons, small craft, or temporary work platforms.

For boaters, its value is predictability on hard, rocky, or sensitive seabeds where a conventional Anchor may not set well. Holding power depends on weight, bottom type, rode angle, and load, so it must be sized as part of the vessel’s Ground Tackle. Strong wind, surge, swell, or Tidal Current can cause dragging if the weight is inadequate.

Before relying on a deadweight mooring, check local rules, inspect attachment points, and allow for chafe and shock loading. PredictWind wind, wave, and tide tools help assess the loads likely at the site, supporting safer mooring choices and better decisions about when to leave a vessel unattended.