Boat size recommendations are for boats of average windage and proportions in 30 knots of wind, average bottom conditions, and moderate protection from open seas. Remember that the loads in 42 knots of wind are twice as much as in 30 knots.
Use three-strand nylon rope, 6-12 ft (2-4 m) of chain and a minimum of 5:1 scope. Also, a minimum of 6 ft (2 m) of chain should be used for every 25 ft (8 m) of water depth. For storm conditions use an anchor one or two sizes larger.
Boat Length: 42-47ft/12-14m
Holding Power: 32° (Hard Sand): 7,500lbs/3,402kg
Holding Power: 32° (Soft Mud): 1,500lbs/680kg
Proof Coil Chain: 3/8"/10mm
Nylon Rope: 5/8"/16mm
Shackle Size: 3/8"/10mm
*Note: Hard sand holding power figures above represent loads actually achieved on production Fortress and Guardian anchors under controlled horizontal pull conditions without dragging or resulting in disabling structural deformation.