Mantus Anchor Swivel
The Strongest Link in Your Chain
The Mantus Swivel is an anchor swivel and shackle in one, designed to keep your chain from twisting and to guide the anchor into the bow roller in the correct orientation. Its integrated shackle design eliminates side loading, and its oblong pin — developed with computer modeling and physical testing — makes the swivel stronger than its corresponding Grade 40 chain. Body: precision-cast, electro-polished 316L stainless. Pin: Duplex stainless steel.
The strongest link – the Mantus anchor swivel is stronger than its corresponding Grade 40 chain. (WLL is 1/5 UBS)
Integrated swivel shackle design completely eliminates side loading, making this the safest anchor swivel on the market.
The pin on the chain side of the swivel is the strength-limiting part since the geometry of the chain determines the pin size. The Mantus anchor swivel and shackle is the first to feature an oblong pin to maximize the pin strength. With the aid of computer modeling and physical testing, we truly created a swivel that is the strongest link.
Note the innovative shackle bolt design – no shackle dog! This slim hex head design (with holes for safety wire) offers a slimmer profile making it easier for translating through your bow roller.
- 316 L Stainless Steel, Precision Cast and Electro-Polished Body
- Pin made from Duplex Stainless Steel and is mechanically polished and electro-polished.
Mantus Anchor Swivel Specifications
| Swivels are available in three sizes : S1 – S2 – S3 | ||||
| Swivel Models | S1 | S2 | S3 | |
| Imperial Chain | 1/4 – 5/16 | 5/16 -3/8 | 3/8 -1/2 | |
| Metric Chain | 6mm – 8mm | 8mm – 10 mm | 10 mm – 14 mm | |
| UBS (Ulitmate Breaking Strength) | 15,000 lb/ 6.8 T | 21,700 lb/ 9.8 T | 35,000 lb/ 16 T | |
| These numbers are used to generate the recommendations below | WLL (Working load limit) (Safety Factor 5) | 3000 lb/ 1.5 T | 4,340 lb / 2 T | 7,000 lb / 3.2 T |
| PRICE | $105 | $132 | $252 | |
Swivel Sizing Guide
| Chain Size (in) | 1/4 (6 – 7mm) | 5/16 (8mm) | 3/8 (10mm) | 7/16 (11mm) | 1/2 (10 – 14mm) | |
| Recommended swivel model for a given chain type and size | Grade 30 Chain | S1 | S1 | S2 | S2 | S3 |
| Grade 40 Chain (G4 HT) | S1 | S1 | S2 | S3 | S3 | |
| Grade 70 Chain | S1 | S2 | S3 | S3 | NA | |
| S1 swivel comes with 7/16 shackle (3/8 shackle optional, with a lower breaking strength) S2 swivel comes with 1/2 shackle (7/16 shackle optional, with a lower breaking strength) S3 swivel comes with 5/8 shackle (1/2 shackle optional, with a lower breaking strength) | ||||||
Understanding your chain
| Imperial Chain Type | G30 (Proofcoil/BBB) (lb) UBS / WLL / WLL inflated* | G40 HT (lb) UBS / WLL / WLL inflated* | G70 HT (lb) UBS / WLL / WLL inflated* | |
| 1/4 | 5,000 / 1,250 | 7750 / 1,938 / 2,600 | 9,450 / 2,350 / 3,150 | UBS -Ultimate Breaking Strength (lb) WLL – Working Load Limit (lb) WLL Inflated* – Working Load Limit inflated using a a different safety factor than is standard. See note below. |
| 5/16 | 7,600 / 1,900 | 11,600 / 2,900 /3,900 | 14100 / 3,500 / 4,700 | |
| 3/8 | 10,600 / 2,650 | 16,200 / 4,100 / 5,400 | 19800 / 4,950 / 6,600 | |
| 7/16 | NA | 21,600 / 5,400 / 7,200 | 26,250 / 6,560 / 8,750 | |
| 1/2 | 18, 000/ 4,500 | 27,600 / 6,900 / 9,200 | 33,900 / 8,475 / 11,300 | |
| *Grade 40/70 chain types claim inflated working load limit values. Typically, chains working load limit is calculated as 1/4th of the ultimate breaking strength. Published WLL for Grade 70 /Grade 40 chain are calculated using the safety factor of 3, or UBS/3 = WLL. (G4 HT) is only 50% stronger than G30 chain and Grade 70 chain is only 20% stronger than G40 chain and 85% stronger than G30 chain. Thus, WLL values we use to size you with the correct swivel are WLL = UBS/4 regardless of the chain type. For Mantus Swivels, we use a safety factor of 5 when determining the WLL recommendations. | ||||
S1 SWIVEL Dimensions
S2 SWIVEL Dimensions
S3 SWIVEL Dimensions
SWIVEL ASSEMBLY INSTRUCTIONS
Frequently asked questions
A swivel connects the anchor to the chain and lets the anchor rotate freely, preventing chain twist as the boat swings at anchor and helping the anchor come up into the bow roller in the right orientation.
For short stays, often not — twist typically unwinds as the windlass retrieves the chain. A swivel earns its place when you anchor in one spot for extended periods or on a mooring system, where twist accumulates.
Stronger than its corresponding Grade 40 chain, with a working load limit of one-fifth of ultimate breaking strength. Conventional swivels fail under side loading when fitted directly to the anchor shank; the Mantus integrated shackle design eliminates side loading entirely.
Match the swivel to your chain: the S1 fits 1/4″–5/16″ Grade 30 or Grade 40 chain; the S2 fits 5/16″–3/8″. For uncommon Grade 70 chain, size up — the S2 covers 5/16″ G70 loads and the S3 covers 3/8″.
Yes, though the pairing accelerates zinc loss on the galvanized parts through galvanic interaction. Galvanized swivels aren’t the answer — they stop swiveling and corrode once their coating wears. Inspect regularly, and isolate the metals where practical.
Every 5 years. Stainless steel degrades over time in salt water, and unlike galvanized steel it corrodes in ways that are hard to see from the outside.
CALL US WITH ANY QUESTIONS:
WITHIN THE US: 1-855-262-6887
BEYOND THE US: 469-226-3468 / 469-878-4083
