Understanding Shackles
Generally Shackles Come two grades:
- Industrial Grade (Type IV A)
- Specialty Alloy Shackles (Type IV B)
Generally if you are trying to match the strength of your chain you can use these rules:
- If sizing for BBB or Proof coil chain use Industrial Grade (Type IV A) shackle, one size bigger than your chain
- If sizing for HT (G4) chain use Specialty Alloy Shackles (Type IV B), one size bigger than your chain
- If sizing for stainless steel chain use a forged SS shackle that is one size bigger than your chain.
- If sizing for duplex chain use a duplex shackle one size bigger than you chain
| Boat Size | Boat Size 0- 14 feet < 1,000 lbs | 14-20 feet < 5000 lbs | 20-30 feet < 11,000 lbs | 30-35 feet < 15,000 lbs | 35-40 feet < 20,000 lbs | 40-45 feet < 40,000 lbs | 45-50 feet < 50,000 lbs | 50-60 feet < 60,000 lbs | 60-70 feet < 70,000 lbs | 70-90 feet < 110,000 lbs |
|---|---|---|---|---|---|---|---|---|---|---|
| Shackle Specialty Alloy Grade (type 4 B) | 5/16 | 5/16 | 5/16 | 3/8 | 3/8 | 7/16 | 7/16 | 1/2 | 1/2 | 5/8 |
| Chain Grade 30 BBB, Proofcoil | 1/4 | 1/4 | 5/16 | 5/16 | 3/8 | 3/8 | 7/16 | 7/16 | 1/2 | 5/8 |
| Chain Grade 40 HT | 1/4 | 1/4 | 1/4 | 5/16 | 5/16 | 3/8 | 3/8 | 7/16 | 7/16 | 1/2 |
***Shackles are sized by their body dimension; the pin is usually one size bigger than the size of the shackle***
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 316 stainless steel.