Two new ratchet blocks just landed in the shop, and both are worth talking about.
The Harken 57 mm Carbo Ratchet Block, Swivel and the Ronstan Series 55 Orbit Ratchet Block with Link Head are built for the same job: keeping your mainsheet under control without burning your hands off. But they go about it in completely different ways.
If you sail an ILCA, an Optimist, a 29er, a 420, a Finn, or just about any dinghy with a mainsheet you have to hold for hours at a stretch, this one matters. Here is what you need to know before you choose.
First, what does a ratchet block actually do?
A ratchet block is a one-way friction block. Pull on the line and it grips. Ease the line and it lets go, or doesn't, depending on the setting. The result: you can hold serious mainsheet load with two fingers instead of crushing it in your fist every tack.
- In light wind you turn the ratchet off. The sheet runs free, the boom flies out for the run.
- In big breeze you turn it on, and the block does the heavy lifting.
Pick the wrong block and you are fighting it half the day. Pick the right one and you forget it is there. That is the goal.
Meet the Harken 57 mm Carbo Ratchet, Swivel
Harken's Carbo range has been a default on dinghy mainsheets for years. You will see it across the ILCA fleet, on Optimists at Garda, on 420s, Fevas, RS-classes, you name it. The reason is simple: it just works.
Specs
- Sheave Ø: 57 mm
- Max line Ø: 10 mm
- Max working load: 227 kg
- Holding power: 10:1
- Switch: manual on/off, accessible from both sides of the block
- Head: stainless swivel shackle, lockable in front, side, or free-swivel
- Body: long-glass-fibre nylon resin sideplates, hard-anodised aluminium sheave, ball-bearing core
Why sailors love it Light. Compact. Proven. The switch is dead simple, the bearings spin freely once disengaged, and the shackle can lock in position or swivel depending on how your sheet wants to track. No frills, no surprises, no excuses.
It is a workhorse, and that is the highest compliment you can pay a piece of dinghy hardware.
Harken 57 mm Carbo Ratchet Block, Swivel
Meet the Ronstan Series 55 Orbit Ratchet, Link Head
Ronstan came at the ratchet block from a different angle, and you can feel it the moment you pick one up.
Specs
- Sheave Ø: 55 mm
- Max rope Ø: 10 mm
- Max working load: 250 kg
- Breaking load: 750 kg
- Holding power: up to 20:1
- Weight: 78 g
- Modes: automatic + manual ratchet, in the same block
- Head: Dyneema® Link, soft, flexible, no metal shackle
- Body: anodised aluminium sheave, carbon-black acetal ball bearings, glass-fibre reinforced nylon frame
Three things stand out.
1. The holding power. Up to 20:1, which is double Harken's 10:1 Carbo. Ronstan got there with their Generation 2 sheave, which uses twelve gripping faces instead of the traditional eight. On paper that is twice the grip. On the water, it is the difference between a wrecked hand and a clean run on a 25-knot reach.
2. The auto/manual switch. Most ratchet blocks make you choose: auto, engages when loaded, releases when slack, or manual, you flick it on and off yourself. The Orbit gives you both modes in the same block. Some sailors live in auto for cleaner asymmetric gybes, others want full manual control. With this one, you don't have to pick a side.
3. The Dyneema Link head. Instead of a stainless shackle, the Orbit attaches with a soft Dyneema loop. No lost shackle pins on the dock. No metal rattle. Lighter. Plays nicely with strops, webbing, and modern attachment systems. Swap-out takes seconds.
Ronstan Series 55 Orbit Ratchet Block with Link Head
Head to head
| Harken Carbo 57 Swivel | Ronstan Orbit S55 Link | |
|---|---|---|
| Sheave Ø | 57 mm | 55 mm |
| Max line Ø | 10 mm | 10 mm |
| Max working load | 227 kg | 250 kg |
| Breaking load | n/a | 750 kg |
| Holding power | 10:1 | up to 20:1 |
| Gripping faces | 8 | 12 |
| Ratchet modes | Manual | Auto + Manual |
| Head | Stainless swivel shackle | Dyneema® Link |
| Weight | light | 78 g |
| Price at LWS | €99.95 | €96.50 |
Which one for which boat?
Honest answer: both work on basically every dinghy where a 50 to 60 mm ratchet belongs. But there are real tendencies worth knowing.
ILCA 6 and ILCA 7 You will see both in the wild here. The Harken Carbo 57 has been the class default for years: bombproof, easy to live with, replacement parts available everywhere. The Ronstan Orbit is the modern challenger, with more holding power for heavy-air days at the front of the fleet, and a Dyneema head that is clean and easy to mount on a primary strop. If you are a heavier ILCA 7 sailor or you race mostly in 15+ knots, the Orbit's extra grip is real. If you want one block you fit once and never think about, the Carbo is very hard to beat.
Optimist Mainsheet loads are lower, but the ratchet still matters, especially for lighter sailors in 12+ knots. Both blocks are popular on the Opti. Coaches often lean Harken for younger sailors because the switch is simpler. Older, more advanced kids gravitate toward the Orbit's auto mode for how cleanly the sheet runs out on bear-aways.
29er, 420, Feva, RS-classes and other asymmetric boats For spinnaker sheets, the Orbit's automatic mode is a genuine edge. It disengages the instant you ease, so gybes stay clean and bear-aways stay fast. If you have ever fought a ratchet through an asymmetric gybe, you know exactly what that fixes.
Finn and heavier-load classes For high-load mainsheets, the Orbit's higher MWL and 20:1 grip start to matter. The Carbo will still do the job, but the Orbit gives you more headroom for the heavy stuff.
So which should you buy?
There is no wrong answer. Both are first-tier. Both will outlast plenty of cheaper kit. Both come with brand reputations built over decades.
- If you want a proven, simple, no-fuss block that is the de facto standard across European dinghy fleets, pick the Harken Carbo 57 Swivel.
- If you want more holding power, dual-mode flexibility, and the cleanest head on the market, pick the Ronstan Orbit Series 55 with Link Head.
Still not sure? Drop us a message on WhatsApp or come find us at the next European regatta. We will match a block to your boat, your weight, and the way you sail. 🤙
In stock now at LiveWatersports:
