Scope

The ratio between the length of anchor rode deployed and the vertical distance from the anchor roller to the seabed.

For example, 30 metres of rode in a total vertical depth of 5 metres gives a scope of 6:1. The vertical distance must include the height of the bow roller or fairlead above the water as well as water depth and the expected rise of tide.

Greater scope generally produces a more horizontal pull on the anchor, but the amount required depends on rode type, holding ground, weather, current, vessel, anchoring duration and available swinging room. Scope is therefore not simply the length paid out and no single ratio is correct for every situation.