Selecting The Proper Anchor Rope

Selecting The Proper Anchor Rope

The following information on anchor ropes is intended as a guide only. If your boat has a high windage factor or is of heavy displacement, you should consider using rope one size larger than recommended for your boat length.

The elasticity of nylon rope makes it ideal for anchoring. It is able to absorb the surge loads created by wave action, therby reducing the possibility of dislodging the anchor from the bottom. A scope of 7:1 is advisable in exposed anchorages and 5:1 in sheltered anchorages (eg 10 metres of water you should have 50 metres of line out in sheltered conditions).

Suggested anchor rope sizes (for winds up to 30 knots)

L.O.A
Beam
Nylon rope
(approx)
(approx)
Length
Diam
4.5m (15')
2m (7')
50m (165')
8mm
6m (20')
2.5m (8')
50m (165')
8mm
7.5m (25')
2.7m (9')
50m (165')
10mm
9m (30')
3m (10')
75m (250')
12mm
10.5m (35')
3.6m (12')
75m (250')
14mm
12m (40')
4m (13')
100m (330')
16mm
15m (50')
4.5m (15')
100m (330')
16mm
18m (60')
4.9m (16')
150m (495')
18mm

Anchor Chain Length

An anchor rode should always include enough chain to ensure a horizontal pull along the bottom. A minimum of 10 metres of chain or the boat length (whichever is the lesser) is recommended. An all chain anchor rode should always be used for anchoring in coral reef areas.