Harken Blocks, Cleats and Dinghy Hardware

We hold over 300 Harken parts, weighted towards the small boat end of the catalogue: blocks from 8mm to 75mm, Cam-Matic and Carbo cam cleats, stand-up springs, eyestraps, clew hooks, universal joints and the McLube products that keep the bearings running.

Harken is has been building high-performance sailboat components in Wisconsin since 1967, and getting a sheave to turn cleanly under load is still what the range is built around.

  • Harken Block Ranges and Where Each One Belongs

    Most dinghies end up carrying three or four different Harken block families because each is built for a different position in the rig.

    Carbo and Carbo Air blocks are the backbone of the small boat range. The sideplates use a glass-reinforced resin that keeps weight down at the mast base and boom end, and the bearings are sealed against grit and salt. The 29mm, 40mm and 57mm sizes cover most dinghy applications.

    T2 soft attach blocks swap the metal head fitting for a Dyneema loop that lashes or splices straight to the boat. They sit closer to the deck, weigh less, and remove the metal-on-gelcoat knocking you get from shackled blocks in light air. The 29mm and 40mm T2s are the sizes dinghy sailors fit most often.

    Micro and 16mm Airblocks handle control lines. Cunningham, outhaul and vang cascades run small diameter rope at moderate load, and a 16mm or 18mm block does that work without the bulk of a mainsheet block.

    Wire blocks take the loads that would flatten a standard sheave, typically on halyard turning points and high-tension control systems.

    Sheave sizes across our Harken range: 8mm, 10mm, 14mm, 16mm, 18mm, 22mm, 25mm, 29mm, 38mm, 40mm, 51mm, 57mm and 75mm.

    Choosing a Harken block by sheave size

    • 16mm to 22mm: control lines, small cascades, low load turning points
    • 29mm: vang, cunningham and outhaul systems, light jib sheets
    • 40mm: mainsheets on smaller dinghies, jib sheet turning blocks
    • 57mm: the standard mainsheet size across most dinghy classes
    • 75mm: mainsheet blocks on larger dinghies and small keelboats

    Check the maximum rope diameter for the block as well as the load rating. A rope too thick for the sheave adds friction where you want to remove it.

  • Harken Ratchet Blocks and Cam Cleats

    A ratchet block holds part of the mainsheet load so your hand doesn't have to, which matters most on a long beat in breeze. We stock over 40 Harken ratchet blocks, so view the range below,

    A standard ratchet is either engaged or free. The Ratchamatic senses the load on the sheet, so in light air it spins freely so the line runs on a gybe, but it engages once the pressure comes on. That behaviour suits dinghy sailors who spend a race day moving between both conditions. The 57mm Carbo ratchet is the common choice for dinghy mainsheets, with the 75mm for larger rigs and small keelboats.

    Harken cam cleats

    Cam-Matic is the range most dinghy sailors know. Micro Cam-Matics suit control lines, standard Cam-Matics handle mainsheets and jib sheets, and the Carbo versions save weight where the loads allow it. Aluminium cams hold up better under sustained high load because composite teeth wear faster on a heavily used sheet.

    Line diameter is the thing to check on the product page. A cam sized for a thick sheet will slip on thin control line, and a cam sized for control line will chew a mainsheet.

    Why Buy Harken Blocks and Cleats from a Sailboats.co.uk?

    We've sold small boat equipment since 1982, and we've stocked class-legal ILCA gear since the class was still called the Laser. That experience in specialty sailing gear matters when you are trying to work out whether a Carbo block or a T2 suits your deck layout, or which fairlead angle will stop a control line binding.

    Our team sails dinghies, so the advice you get on the phone comes from people who have rigged the same systems you're asking about. If you need a Harken part that is not listed, ask us and we will check whether we can source it.

FAQs About Harken Sailing Blocks and Cleats

Which Harken block should I use for a dinghy mainsheet?

For most dinghy classes, a 57mm Carbo ratchet block is the standard mainsheet choice. Smaller boats and lighter rigs run 40mm, and larger dinghies or small keelboats move up to 75mm. Check your class rules first because some one-design classes specify what you can fit.

What is the difference between Carbo and T2 blocks?

Carbo blocks attach with a conventional metal head fitting, usually a shackle or swivel. T2 blocks attach with a Dyneema soft loop that ties or splices directly to the boat. T2s are lighter, sit flatter against the deck, and are quicker to reposition if you change your rig setup.

How does a Ratchamatic differ from a standard ratchet block?

A standard ratchet is switched on or off by hand. The Ratchamatic responds to load so the ratchet disengages when the sheet is unloaded and engages when the pressure builds. It saves you switching the ratchet manually as the breeze comes and goes.

Can Harken blocks be serviced?

Riveted Carbo blocks are sealed units and cannot be opened to replace bearings, so a damaged one is replaced. Cam cleats are a different case, as we stock replacement springs and parts that will bring a tired cleat back to full snap.

How should I look after Harken blocks and cleats?

Rinse with fresh water after every sail, particularly in salt. Salt crystals in a bearing race do more damage than anything else. Avoid grease and heavy oil, which hold sand and grit against the bearings. McLube OneDrop suits ball bearing blocks, and McLube Sailkote works well on cam jaws and traveller tracks.

Can I fit Harken hardware to any dinghy?

Yes. Harken parts are not class-specific, so they retrofit to ILCA, Topper, RS Aero, Wayfarer, 420 and most other classes. Check your class rules before changing a control system on a one-design boat.

Harken Collections