Selection Guide
Boat anchor 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.
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.
FORTRESS ANCHORS
Mobile users please scroll to the right to find your boat length and anchor model selection.
| Boat Length | ft | 16'-27' | 28'-32' | 33'-38' | 39'-45' | 46'-51' | 52'-58' | 59'-68' | 69'-89' | 90'-150' |
| m | 5-8m | 8-10m | 10-12m | 12-14m | 14-15m | 16-18m | 18-21m | 21-27.1m | 27.4-46m | |
| Fortress Model | FX-7 | FX-11 | FX-16 | FX-23 | FX37 | FX-55 | FX-85 | FX-115 | FX-125 | |
| Weight | lb (kg) | 4 (1.8) | 7 (3.2) | 10 (4.5) | 15 (6.8) | 21 (9.5) | 32 (14.4) | 47 (21.2) | 60 (27.2) | 69 (31.1) |
| Replaces Steel Anchors | lb | 6-9 | 10-13 | 14-18 | 19-28 | 33-50 | 50-65 | 70-90 | 90-100 | 100-170 |
| kg | 3-4 | 5-6 | 6-8 | 9-13 | 15-23 | 23-29 | 32-41 | 42-44 | 45-77 | |
| HOLDING POWER | ||||||||||
| Working Load | lb | 700 | 900 | 1,250 | 2,000 | 3,000 | 4,000 | 5,250 | 6,000 | 6,750 |
| kg | 318 | 408 | 567 | 907 | 1,361 | 1,814 | 2,381 | 2,721 | 3,062 | |
| 32° Hard Sanding Holding | lb | 2,800 | 3,600 | 5,000 | 8,000 | 12,000 | 16,000 | 21,000 | 24,000 | 27,000 |
| kg | 1,270 | 1,633 | 2,268 | 3,629 | 5,443 | 7,258 | 9,526 | 10,886 | 12,247 | |
| 45° Soft Mud Holding | lb | 840 | 1,080 | 1,500 | 2,400 | 3,600 | 4,800 | 6,300 | 7,200 | 8,100 |
| kg | 381 | 490 | 680 | 1,089 | 1,633 | 2,177 | 2,858 | 3,265 | 3,674 | |
| 32° Soft Mud Holding | lb | 420 | 540 | 750 | 1,200 | 1,800 | 2,400 | 3,150 | 3,600 | 4,050 |
| kg | 191 | 245 | 340 | 544 | 816 | 1,089 | 1,429 | 1,633 | 1,837 | |
| DIMENSIONS | ||||||||||
| "A" Shank Length | in (mm) | 24" (610) | 27" (686) | 31" (787) | 36" (914) | 40" (1,016) | 46" (1,168) | 51" (1,295) | 51" (1295) | 56" (1,422) |
| "B" Fluke Length | in (mm) | 14" (356) | 16" (406) | 18" (457) | 21" (533) | 24" (610) | 27" (686) | 30" (762) | 33" (838) | 33" (838) |
| "C" Stock Length | in (mm) | 19" (483) | 22" (559) | 25" (635) | 29" (737) | 32" (813) | 37" (940) | 41" (1,041) | 45" (1,143) | 45" (1,143) |
| SUPPORT HARDWARE | ||||||||||
| Proof Coil Chain | in (mm) | 3/16" (5) | 1/4" (6) | 5/16" (8) | 3/8" (9) | 3/8" (9) | 1/2" (13) | 1/2" (13) | 1/2" (13) | 1/2" (13) |
| Nylon Rope ** | in (mm) | 3/8" (9) | 3/8" (9) | 1/2" (13) | 5/8" (16) | 3/4" (19) | 7/8" (22) | 1" (25) | 1 1/4" (32) | 1 1/4" (32) |
| Shackle Size | in (mm) | 1/4" (6) | 1/4" (6) | 5/16" (8) | 3/8" (10) | 7/16" (12) | 1/2" (12) | 5/8" (16) | 5/8" (16) | 5/8" (16) |
GUARDIAN ANCHORS
| Boat Length | ft | 12'-16' | 17'-22' | 23'-27' | 28'-33' | 34'-41' | 42'-47' | 48'-53' | 54'-62 | 63'-72' |
| m | 4-5m | 5-7m | 7-8m | 8-10m | 10-12m | 12-14m | 14-16m | 16-19m | 19-22m | |
| Guardian Model | G-5 | G-7 | G-11 | G-16 | G-23 | G-37 | G-55 | G-85 | G-125 | |
| Weight | lb (kg) | 2.5 (1.1) | 2.9 (1.3) | 5(2.26) | 7 (3.2) | 13 (5.9) | 18 (8.2) | 29 (13.1) | 42 (19) | 65 (29.3) |
| Replaces Steel Anchors | lb | 4-6 | 6-9 | 10-13 | 14-18 | 19-28 | 33-50 | 50-65 | 70-90 | 100-170 |
| kg | 2-3 | 3-4 | 5-6 | 6-8 | 9-13 | 15-23 | 23-29 | 32-41 | 45-77 | |
| HOLDING POWER | ||||||||||
| Working Load | lb | 350 | 575 | 750 | 1,075 | 1,625 | 2,500 | 3,500 | 4,625 | 6,000 |
| kg | 159 | 261 | 340 | 488 | 737 | 1,134 | 1,588 | 2,098 | 2,722 | |
| Hard Sanding Holding | lb | 1,050 | 1,725 | 2,250 | 3,225 | 4,875 | 7,500 | 10,500 | 13,875 | 18,000 |
| kg | 476 | 782 | 1,021 | 1,463 | 2,211 | 3,402 | 4,763 | 6,294 | 8,165 | |
| Soft Mud Holding | lb | 210 | 345 | 450 | 645 | 975 | 1,500 | 2,100 | 2,775 | 3,600 |
| kg | 95 | 156 | 204 | 293 | 442 | 680 | 953 | 1,259 | 1,633 | |
| DIMENSIONS | ||||||||||
| "A" Shank Length | in (mm) | 19" (483) | 22" (559) | 25" (635) | 29" (737) | 33" (838) | 38" (965) | 43" (1.092) | 48" (1,219) | 53" (1,356) |
| "B" Fluke Length | in (mm) | 11" (279) | 13" (330) | 15" (381) | 17" (432) | 19" (483) | 22" (559) | 25" (635) | 28" (711) | 31" (787) |
| "C" Stock Length | in (mm) | 16" (406) | 18" (457) | 20" (508) | 23" (584) | 27" (686) | 31" (787) | 35" (889) | 39" (991) | 43" (1,092) |
| SUPPORT HARDWARE | ||||||||||
| Proof Coil Chain | in (mm) | 3/16" (5) | 3/16" (5) | 3/16" (5) | 1/4" (6) | 5/16" (8) | 3/8" (9) | 3/8" (9) | 1/2" (13) | 1/2" (13) |
| Nylon Rope ** | in (mm) | 3/8" (9) | 3/8" (9) | 3/8" (9) | 3/8" (9) | 1/2" (13) | 5/8" (16) | 3/4" (19) | 7/8" (22) | 1" (25) |
| Shackle Size | in (mm) | 3/16" (5) | 3/16" (5) | 1/4" (6) | 1/4" (6) | 5/16" (8) | 3/8" (10) | 7/16" (12) | 1/2" (12) | 5/8" (16) |
For all tech questions please email techsupport@fortressanchors.com and a Fortress Marine Anchors representative will respond in 24-48 hours.
Have questions? Check out our frequently asked questions page.
