Guardian Anchors

Guardian Anchors are the Safer, More Affordable Alternative to Heavy Steel Anchors


Benefiting from years of Fortress Anchor R&D, the Guardian model offers excellent quality, performance and economy. Guardian Anchors are made from the same high tensile, corrosion resistant aluminum magnesium alloy and manufacturing precision as Fortress.

The use of slightly smaller extrusion profiles and the elimination of some of Fortress’ extra features, such as anodizing, adjustable fluke angles, and several machining steps resulted in a very affordable alternative to those heavy, rust-prone steel anchors.

While the Fortress Anchor can be adjusted from 32 degrees to 45 degrees for extra holding power, the Guardian Anchor is limited to one single 32-degree angle.


All Guardian aluminum anchors feature Mud Palms designed to help the anchor set faster in any type of sea bottom. Mud Palms create a “lift” to the crown of the anchor, causing the flukes to point more directly to the seabed. This helps the anchor set faster … in any bottom.

Guardian aluminum anchors are available in nine sizes for boats between 12 ft. (4 m) and 72 ft. (22 m)!

  • The Fortress anchors had far greater holding power than any other anchor tested.

    The United States Navy
  • We tested the lightweight Fortress FX-23, and the results were remarkable!

    - Bateaux
  • The Fortress Anchor outperforms other anchors of comparable size.

    - Cruising World
  • I've used a Fortress as my primary anchor in sand and mud bottoms for more than 20 years. I have found the Fortress to be thoroughly dependable.

    - Elbert S. Maloney, Author "Chapman's Piloting & Seamanship"
  • Fortress makes it practical for boat owners to carry a large storm anchor they might previously had no room for.

    - Motor Boating & Sailing
  • After almost a full year of heavy-duty cruising, there is no way I would revert to the old heavy steel anchors again.

    - Multihulls, 300 Day Cruising Test
  • The Fortress FX-7 wins again on our second test with impressive performance.

    - Nautica (Brazil), tests conducted in '96 & '10
  • The Fortress FX-23 attained far superior holding power than its much heavier opponents.

    - Neptune (France)
  • Be assured that on the combination of anchors and the clay type bottom we tested in the published test, the Fortress anchor performed absolutely best.

    - PAKRYSS (Sweden)
  • The Fortress is the best fluke type anchor we have ever tested.

    - Pontoon & Deck Boat
  • Fortress carries the 'form, not weight' theory to its logical conclusion.

    - Power & Motor Yacht
  • The perfect anchor? We like Fortress!

    - PowerBoat Reports
  • Fortress anchors have at lease twice the holding power of the other types tested.

    - Practical Boat Owner (UK)
  • The Fortress is hard to beat. We continue to be impressed.

    - Practical Sailor
  • A well made aluminum anchor is at least a viable alternative to the various already proven designs in steel...the Fortress anchors tested highest.

    - Sail
  • With its light weight, quick setting and retrieval, enormous holding power at a variety of scopes, and easy stowability, the Fortress ranked high among all the anchors we tested.

    - Sail, Oct. '06
  • The Fortress FX-16's holding power is excellent in all conditions.

    - Trailer Boats
  • Fortress represents the best in anchor technology.

    - Yachting
  • The Fortress set very quickly during our tests. It outperformed all other anchors by a significant margin.

    - Yachting Monthly (UK)
  • The Fortress's ability to dig in instantly and hold was astonishing - especially as it weighs only 22lb, one of the lightest anchors tested.

    - Yachting Monthly (UK), Dec. '06
  • We were astonished by its holding power of more than 3 tonnes, equivalent to the cable load of a 12m (40ft) yacht in a hurricane.

    - Voiles et Voiliers (France), July '09 & Yachting Monthly (UK), Nov '09


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 line, 6-12 ft (2-4m) of chain and a minimum of 5:1 scope. A minimum of 6 ft (2m) of chain should be used for every 25 ft (8m) of water that you usually anchor in. For storm conditions, we recommend using an anchor one or two sizes larger.

Boat Lengthft12'-16'17'-22'23'-27'28'-33'34'-41'42'-47'48'-53'54'-6263'-72'
Guardian ModelG-5G-7G-11G-16G-23G-37G-55G-85G-125
   Weightlb (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 Anchorslb4-66-910-1314-1819-2833-5050-6570-90100-170
Working Loadlb3505757501,0751,6252,5003,5004,6256,000
Hard Sanding Holdinglb1,0501,7252,2503,2254,8757,50010,50013,87518,000
Soft Mud Holdinglb2103454506459751,5002,1002,7753,600
"A" Shank Lengthin (mm)19" (483)22" (559)25" (635)29" (737)33" (838)38" (965)43" (1.092)48" (1,219)53" (1,356)
"B" Fluke Lengthin (mm)11" (279)13" (330)15" (381)17" (432)19" (483)22" (559)25" (635)28" (711)31" (787)
"C" Stock Lengthin (mm)16" (406)18" (457)20" (508)23" (584)27" (686)31" (787)35" (889)39" (991)43" (1,092)
Proof Coil Chainin (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 Sizein (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)

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.

**Rope recommendations are based on manufacturer’s ratings of 25% of breaking strength. Rope must be in good condition.

For tech questions please email us at and a Fortress Marine Anchors representative will respond in 24-48 hours.