Cruising Solutions
Mantus Anchor Swivel S3
Mantus Anchor Swivel S3
SKU:US3
- 3/8–1/2 in / 10–14 mmChain fit
- 7,000 lb / 3,175 kgWorking load limit
- 316L body + 2507 pinStainless construction
Heavy-duty anchor-to-chain swivel for 3/8–1/2 in (10–14 mm) chain. Confirm chain grade as well as diameter before sizing.
See full product details and specificationsCouldn't load pickup availability
- Ships in 1–5 business days
- 30-day returns
- Advice from real cruisers
Mantus Anchor Swivel S3 - Strongest Marine Anchor Swivel
Experience unmatched strength and safety with the Mantus Anchor Swivel S3, designed to be the strongest link in your anchoring system. Built from 316L marine-grade stainless steel, this swivel is stronger than its corresponding Grade 40 chain, giving you total confidence when anchoring in any conditions.
The integrated swivel shackle design eliminates side loading - the leading cause of swivel failure - making the S3 the safest and most reliable anchor swivel available. Engineered for precision and durability, every component ensures smooth rotation, even under heavy load, while maintaining a compact, low-profile fit that suits most anchor and chain setups.
Shipping & lead times
Shipping & lead times
We're a small team of boaters and we pack orders within 1–5 business days (no weekend or holiday packing). You'll get an email with tracking as soon as a label goes on your box.
Specialty items — fire extinguishers (dangerous goods) and low-stock or built-to-order gear — can take longer; the product description will say so. On a tight timeline or meeting your boat somewhere specific? Contact us and we’ll work out the fastest way to get gear to you.
International orders ship DDU: local duties, taxes, and customs fees are the buyer’s responsibility. Full details in our shipping policy.
Returns & refunds
Returns & refunds
30-day returns from the date of purchase. Items must be unused, in the original packaging with all cables and accessories, with proof of purchase.
Contact us before shipping anything back — we’ll send the return form that must accompany your return. Fire extinguisher and lithium battery items carry a $15 administrative fee on returns.
Read the full refund policy.
Ask a cruiser before you buy
Ask a cruiser before you buy
Everyone here is a current or past cruiser — we’ve docked short-handed, re-rigged at anchor, and chased 12V gremlins too. Not sure this is the right fit for your boat? Send us your question before you order and we’ll give you a straight answer.
Mantus swivel sizing and construction
The integrated shackle connects directly to the anchor, avoiding the side loading that can occur when a conventional shackle bears across a swivel eye. The body is precision-cast 316L stainless steel and the oblong chain pin is 2507 duplex stainless steel.
| Model | Chain diameter | Working load limit | Ultimate breaking strength | Included anchor shackle |
|---|---|---|---|---|
| S1 | 1/4–5/16 in (6–8 mm) | 3,000 lb (1,360 kg) | 15,000 lb (6,804 kg) | 7/16 in (11 mm) |
| S2 | 5/16–3/8 in (8–10 mm) | 4,340 lb (1,970 kg) | 21,700 lb (9,843 kg) | 1/2 in (13 mm) |
| S3 | 3/8–1/2 in (10–14 mm) | 7,000 lb (3,175 kg) | 35,000 lb (15,876 kg) | 5/8 in (16 mm) |
Choose by chain grade as well as diameter
For 3/8 in (10 mm) Grade 30 or Grade 40 chain, S2 is normally the appropriate size; S3 is used at that diameter when Grade 70 strength requires it. Oversizing can create bow-roller fit and anchor-setting problems.