Mantus Anchor Shackles Stainless steel anchor shackle designed for the job: A flush hex head allows for smooth passage through the bow roller A socket wrench or a crescent wrench could be easily used to open or close the pin even after many months of use. A hole in the hex head is designed to safety wire the pin to prevent pin loosening. Mantus boat anchor shackles are forged and use high quality 2205 Duplex stainless steel. Size Working Load Limit (lbs) Recommendations* Ultimate Breaking Strength (lbs) 2205 Duplex Forged Stainless Shackles Hi Test G4 Chain G3 Chain Proof-coil, BBB 2205 Drop Forged Stainless Shackles Hi Test G4 Chain G3 Chain Proof-coil, BBB 1/4 1,300 2,600 / 1,950 1,300 6,500 7,800 5,200 5/16 1,850 3,900 / 2,900 1,900 9,100 11,700 7,600 3/8 1,950 5,400 / 4,050 2,650 9,750 16,200 10,600 7/16 2,600 7,200 / 5,400 N/A 13,000 21,600 N/A 1/2 3,900 9,200 / 6,900 4,500 19,500 27,600 18,000 5/8 5,200 — — 26,000 — — *These are manufacturer’s recommendations and often differ from one marine manufacturer to another. Our anchor chain shackles are strong enough to use with Hi Test Chain—just pick one size larger than the chain. *The working load limit called out on our anchor shackles is 1/6th of the breaking strength vs the ratio of 1/5th for the Grade A shackles. So, when sizing our shackles, it is more useful to compare the ultimate breaking strength of the shackle to that of the chain. Using stainless steel shackle with galvanized chain: When sizing a stainless steel shackle for your anchor and Grade 30 galvanized chain, pick a shackle one size larger than the chain and the shackle will be the same strength as the chain. When sizing a stainless steel shackle for your anchor and Grade 40 galvanized chain, only a shackle one size larger will fit and the shackle will be 60 – 70% the strength of the chain. We recommend using a Mantus swivel to match the strength of the shackle connection to that of the Grade 40 chain. Shackle Size A B C D E F G H 1/4 inch 0.47 0.31 1.13 0.25 0.78 0.59 1.31 1.80 5/16 inch 0.53 0.38 1.22 0.31 0.84 0.74 1.40 2.16 3/8 inch 0.66 0.44 1.44 0.38 1.03 0.90 1.8 2.60 7/16 inch 0.75 0.50 1.65 0.43 1.14 1.00 1.96 2.9 1/2 inch 0.85 0.62 2.00 0.47 1.30 1.24 2.22 3.43 5/8 inch 1.08 0.74 2.6 0.61 1.69 1.57 2.88 4.25 3/4 inch 1.25 0.85 3.0 0.77 2.00 1.66 3.45 5.00
