Spinlock's XX Powerclutch range holds the same 8-12 mm line in three load tiers — the XXA to 1,800 kg, the XXB to 2,350 kg, and the XXC to 2,350 kg in a lighter carbon-and-titanium body — so the right pick comes down to load class and construction, not rope diameter. MAURIPRO stocks all three, ready to match to your genoa or spinnaker halyard.
This is written for the performance cruiser or racer (~35-50 ft) replacing a worn primary clutch or speccing hardware for a new genoa or spinnaker halyard, staring at three near-identical black Spinlock housings stamped XXA, XXB, or XXC with no obvious difference in rope range. All three clutch the same 8-12 mm (5/16-1/2 in) line and share the same pull-up-to-release, push-down-to-clutch action — what actually changes model to model is the rated load, the jaw material, and the body construction, and getting it wrong either underrates your highest-load halyard or pays a premium for weight savings a straightforward cruising boat will never use.
Spinlock Powerclutches at a glance
| Model | Line range | Load rating (per Spinlock) | Best for | Example |
|---|---|---|---|---|
| XXA | 8-12 mm (5/16-1/2 in) | Up to 1,800 kg (3,970 lb) | Genoa/spinnaker halyards on 35-50 ft performance yachts; standard alloy jaws | Single XXA Powerclutch, 8-12mm |
| XXB | 8-12 mm (5/16-1/2 in) | Up to 2,350 kg (5,180 lb) | Blended-cover lines on powered/winch-assisted systems; ceramic jaws resist abrasion | Single XXB Powerclutch w/ Ceramic Jaws, 8-12mm |
| XXC | 8-12 mm (5/16-1/2 in) | Up to 2,350 kg (5,180 lb) | Same top-end load as the XXB in a lighter carbon/titanium body; grand-prix and weight-critical racing | Single XXC Powerclutch, 8-12mm |
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What's the real difference between the XXA, XXB, and XXC?
It's load rating and jaw/body construction, not rope range — all three cover the identical 8-12 mm line, per Spinlock's own product specifications. The XXA is the base model: standard alloy jaws rated to 1,800 kg, which Spinlock markets as 50% more holding power than a conventional rope clutch, built for genoa and spinnaker halyards on 35-50 ft performance yachts. The XXB steps up to ceramic-coated jaws and a 2,350 kg rating, and Spinlock specifically positions it for "enhanced performance on small diameter blended covered lines" with "excellent resistance to abrasion on powered hoists and control" — in other words, halyards on winch-assisted or powered systems that cycle the line hard and fast. The XXC matches the XXB's 2,350 kg rating but is built with a lightened handle and body, locally reinforced with unidirectional carbon fiber, and uses titanium in place of stainless steel for critical components, with ceramic jaws to resist the heat generated at high line speed. Spinlock's own guidance is to choose the XXC "for working loads and diameters that can't be held reliably with conventional clutches but where the winched release of the ZS [Jammer] is impractical."
How do you match your line's diameter and load to the right Powerclutch?
Since all three share the same 8-12 mm range, sizing comes down to working load and rope construction, not diameter. Check the halyard's actual working load rather than assuming diameter tells the whole story: Dyneema and other low-stretch cores let sailors run this same 8-12 mm range at higher loads than traditional double-braid, so a thin, high-tech-cored halyard can approach the XXA's 1,800 kg ceiling well before a double-braid line of the same diameter would. If the line's cover blends polyester with aramid, Technora, or similar high-tech fibers, the XXB's ceramic jaws are worth the step up from the XXA's standard jaws regardless of load, since Spinlock built that jaw specifically for blended covers. And if the system winches or powers the line hard and often — a powered halyard hoist, for example — favor the XXB or XXC's ceramic jaws over the standard XXA to resist the heat and wear that comes with fast, repeated cycling.
Which should you choose for your boat?
Choose the XXA for standard genoa and spinnaker halyards on a 35-50 ft performance cruiser or racer, where 1,800 kg covers the load with margin and the lower price makes sense on a straightforward flat-deck or side-mount installation. Choose the XXB when that same halyard or sheet load runs closer to 2,350 kg, or when the line is a blended-cover rope on a winch-assisted or powered system where the ceramic jaws' abrasion resistance earns its keep over the standard alloy jaws. Choose the XXC when you need XXB-class holding power in the lightest, most weight-conscious build Spinlock offers in this range — grand-prix or weight-critical race programs — or, per Spinlock's own guidance, when the load exceeds what a conventional clutch can hold reliably but a winch-released ZS Jammer isn't practical for that line's position or duty cycle.
Expert notes
From our rigging bench: sailors sizing a Powerclutch off diameter alone often default straight to the XXA since all three share the same 8-12 mm range — check the line's actual working load and cover material first, because the XXA's standard jaws are not the ceramic-jaw XXB's equal on a blended-cover halyard even though both physically fit the same 8-12 mm cam.
On boats retrofitting a powered halyard system, we also flag mounting orientation: the XXA, XXB, and XXC are each available bolted flat-deck or side-mounted port/starboard, and the side-mount kits use a different fastener pattern than the standard base — confirm which your deck layout needs before ordering, since the two don't share hardware.
Common mistakes
- Picking a Powerclutch by rope diameter alone. The XXA, XXB, and XXC all cover the identical 8-12 mm line — load class and jaw material are what actually separate them, not the rope size.
- Assuming the XXC's lighter, carbon-reinforced build outrates the XXB. Both are rated to the same 2,350 kg per Spinlock's specifications; the XXC's advantage is weight and heat resistance at high line speed, not extra holding power.
- Running a blended-cover rope through the XXA's standard alloy jaws. The ceramic-jaw XXB and XXC hold blended covers more consistently and resist the wear standard jaws see on those ropes.
- Ordering the standard bolted base when the deck layout calls for a side mount. Confirm mounting style before ordering — the side-mount kits use a different fastener pattern than the flat-deck base.
Frequently asked questions
Which Spinlock Powerclutch do I need?
Match load class, not diameter: all three — XXA, XXB, and XXC — cover the same 8-12 mm line, but the XXA is rated to 1,800 kg while the XXB and XXC are both rated to 2,350 kg, per Spinlock's own specifications. MAURIPRO stocks all three.
What's the difference between the Spinlock XXB and XXC Powerclutch?
Both are rated to the same 2,350 kg, but the XXC swaps to a carbon-reinforced body with titanium hardware in place of stainless steel for a lighter build, while the XXB keeps a standard alloy body with ceramic jaws. Spinlock recommends the XXC specifically where weight matters or a winch-released ZS Jammer isn't practical.
Is the Spinlock XXA strong enough for a spinnaker halyard?
Yes, on most 35-50 ft performance yachts — Spinlock rates the XXA to 1,800 kg, which it markets as 50% more holding power than a conventional rope clutch, built specifically for genoa and spinnaker halyards in this size range.
Can a Spinlock Powerclutch be side-mounted?
Yes — the XXA, XXB, and XXC are each available in bolted side-mount versions (port or starboard) in addition to the standard flat-deck base, using a different fastener pattern than the bolted base.
Does the Spinlock Powerclutch work with Dyneema and other low-stretch line?
Yes, though check working load rather than diameter — Dyneema and other low-stretch cores let sailors run this 8-12 mm range at higher loads than traditional double-braid, so a thin, high-load halyard can approach the XXA's 1,800 kg ceiling sooner than diameter alone would suggest.
Recommended gear
Spinlock Single XXA Powerclutch, 8-12mm — the standard-load pick for most genoa and spinnaker halyards.
Spinlock Single XXB Powerclutch w/ Ceramic Jaws, 8-12mm — for blended-cover line on powered or winch-assisted systems.
Spinlock Single XXC Powerclutch, 8-12mm — the same top-end load in Spinlock's lightest carbon-and-titanium build.
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