Which anchor for which boat and use?

Max. boat length Boat displacement Min. anchor weight ?schackle ?chain Nylon rope ?/font>
Dinghy, tender, Optimist - 2kg 8mm 6mm 6mm
Dinghy, inflatable boat
Small catamaran up to 4 m
300kg 3.5kg 8mm 6mm 6-8mm
Boat up to 5.50m 800kg 6kg 8mm 6mm 10mm
6.50m 1000kg 8kg 8mm 6-7mm 10mm
7.50m 2000kg 10kg 10mm 8mm 14mm
9m 3000kg 12kg 10mm 8mm 14mm
10.50m 4500kg 14kg 10mm 8mm 14mm
12.50m 8000kg 16kg 12mm 10mm 18mm
16m 12000kg 20kg 12mm 10mm 18mm
18m 16000kg 24kg 16mm 12mm 22mm
20m 20000kg 34kg 16mm 14mm 24mm
25m 30000kg 40kg 16mm 14mm 24mm
+ 25m + 30000kg 60kg 18mm 16mm 28mm

The anchor weight is only given as an indication, per length of boat.  However, this criteria alone is not sufficient, and your anchor selection should also recognise the specific construction of your vessel.