Mantus Swivel

Mantus Anchor Swivel

The Strongest Link in Your Chain

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.


Swivels are available in three sizes : S1 – S2 – S3


Swivel Models




Imperial Mantus swivels fit all Imperial chain sizesImperial Chain1/4 – 5/165/16 -3/83/8 -1/2
Universal Mantus swivels fit metric chainMetric Chain6mm – 8mm8mm – 10 mm11 mm – 13 mm
 UBS (Ulitmate Breaking Strength)11,000 lb/ 5 T19,800 lb/ 9 T35,000 lb/ 16 T
These numbers are used to generate the recommendations belowWLL (Working load limit) (Safety Factor 5)2,200 lb/ 1T3,960 lb / 1.8 T7,000 lb / 3.2 T
 Chain Size (in)1/45/163/87/161/2
Recommended swivel model for a given chain type and sizeGrade 30 ChainS1S1S2S3S3
Grade 40 Chain(G4 HT)S1S1 or S2S2 or S3S3S3
Grade 70 ChainS1S2S3S3NA

When sizing for 5/16 Grade 40 chain one has an option between S1 and S2 swivels: S1 is lightly undersized, it has the same breaking load as the chain and slightly lower WLL. For boats under 40 feet we recommend the S1 swivel and for boats over 40 feet we recommend the S2 swivel.

Imperial Chain TypeG30 (Proofcoil/BBB) (lb) UBS / WLL / WLL inflated*G40 HT (lb) UBS / WLL / WLL inflated*G70 HT (lb) UBS / WLL / WLL inflated* 
1/45,000 / 1,2507750 / 1,938 / 2,6009,450 / 2,350 / 3,150UBS -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.
5/167,600 / 1,90011,600 / 2,900 /3,90014100 / 3,500 / 4,700
3/810,600 / 2,65016,200 / 4,100 / 5,40019800 / 4,950 / 6,600
7/16NA21,600 / 5,400 / 7,20026,250 / 6,560 / 8,750
1/218, 000/ 4,50027,600 / 6,900 / 9,20033,900 / 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.