Optimist Rope Guide

From replacing a single sail tie to renewing the whole boat, this guide covers the ropes, lashings and shockcord used on an Optimist. Find out what each line does, which sizes suit the different setups and which ready-made replacements are available.

Start with your existing rig. School, Silver, Blackgold and Optimax spars do not all use the same lines. The sizes below describe the specific products or setups shown. Where a manufacturer does not publish a universal cut length, measure your working setup or choose the matching ready-made assembly.

Shop Optimist ropes and lines | Shop rope by diameter

1. Optimist mainsheets

The mainsheet is the rope the sailor handles most. Choose it for comfortable grip, smooth movement through the blocks and compatibility with the boat’s purchase system. A thicker handling section can be comfortable without needing the same diameter throughout a tapered sheet.

The Pro sheet has a 3.3m handling section and tapered sections of 1.8m and 2.5m. Fit it in the intended orientation so the thicker section sits where the sailor handles it.

2. Complete mainsheet packs and replacement blocks

If your blocks also need replacing, a complete system can be simpler than choosing the components individually. The following are alternatives, rather than parts you need to buy together.

Option	What is included or replaced
School mainsheet system — 1375	6m standard sheet, plain-bearing fiddle blocks, snap shackle, block spring and plate shackles. Intended for school and training use.
Racing mainsheet system — 1376	6m standard sheet, Windesign 57mm ratchet block, two 38mm ball-bearing blocks, snap shackle, block spring and plate shackles.
Pro Racing mainsheet system — 13761	1379 double-tapered sheet, Harken 57mm Carbo ratchet block with link, Harken 40mm block, 1314 Harken block with Dyneema strop, plate shackles and block spring.
Harken 40/29mm link block with shackle — 1321	A linked block assembly for a compatible mainsheet arrangement. This is a hardware replacement, not a mainsheet rope or complete system.
Harken mainsheet extender — 1314	A 40mm block on a Dyneema strop with shackle. Useful when replacing the complete extender assembly.

3. Sprit halyard: primary line and control tail

The sprit halyard tensions the sprit that supports the upper corner of the sail. Racing arrangements usually have a low-stretch primary line and a separate adjustment line. School rigs can use a simpler polyester halyard.

• Primary line: carries the load between the sprit and the halyard hardware. Check the eyes, splices and contact points around the blocks.
• Control tail: the part pulled by the sailor and held in the cleat. It needs suitable grip and a diameter that works with the cleat and handle.

Length: choose the assembly that matches your mast, or measure the primary line and control tail separately. Measure finished eyes as well as the rope between them. Changing the block, ring or handle can change the required length. A replacement line-and-block assembly may reuse parts of your existing system; it is not automatically a complete mast rigging pack.

For a custom primary, 3mm D12 78 is a low-stretch rope option where your rig calls for 3mm Dyneema. Splicing allowance must be added to the required finished dimensions.

4. Kicker / vang / boom downhaul

These names are used for the line pulling the boom down towards the mast. Some product listings call it a downhaul. Identify both sections on your rig before replacing it: the primary around the boom and, where fitted, the thicker control tail at the cleat.

Part	Size / option	Length guidance
Racing primary	1364 ready-made 3mm Dyneema vang line, with one spliced eye	Open end is fitted around the boom. Match your boom diameter and attachment.
Racing control tail	OX36DHC 5mm Technora/Dyneema secondary line	Check compatibility with your existing primary and cleat; retain enough travel to release the system.
School-rig vang	6mm polyester in the 1056 School rigging pack	For the specified School spar sets; not a universal racing-rig cut length.

5. Outhaul

The outhaul pulls the clew towards the end of the boom and adjusts tension along the foot of the sail. It must run through the boom-end arrangement and hold securely in its cleat.

• Pro upgrade option: 3.5mm HT polyester, supplied in the 1370 Pro Line package.
• School-rig option: 4mm polyester, included in the 1056 School rigging pack.
• Existing racing booms: different models use different diameters and constructions. Match the current rope and cleat, or contact us before substituting.

Length: the 2026 class rules limit the outhaul rope to 1.2m maximum; this is a rule limit, not a universal cut recommendation. Measure your arrangement. The separate clew tie is covered below.

6. Boom bridle, ring ties and mainsheet strops

The bridle is the span beneath the boom supporting the mainsheet attachment. Other arrangements use individual strops. Inspect the rope at every lacing eye, ring and block attachment.

• Ready-made bridle: look for the 3mm bridle with stainless-steel ring, code 1360, in our Optimist ropes and lines.
• Custom bridle: 3mm D12 78 is an option for a design specifying 3mm Dyneema.
• Ring-positioning ties: 3mm Vectran trimline is listed for Optimist corner and bridle ties.
• Mainsheet extender strop: choose the 1314 block and strop assembly, or find the replacement line for EX1314 in our rope range.

Length: measure the complete installed arrangement. A bridle, block strop and extender are not interchangeable lengths. The 2026 rules limit span-to-boom clearance to 100mm; attachment points and rings must not slide.

7. Sail ties: mast, boom and corners

Use purpose-made low-stretch lacing line. Renew worn ties before they fail, especially where they pass through sail eyelets. A ready-cut set is the simplest way to replace the whole sail’s lacing.

The 1336 sail tie set and 1336Y yellow set each contain:

• 14 × 1.2mm ties, each 42cm long, for mast and boom lacing.
• 5 × 2.2mm ties, each 45cm long, for the heavier corner/tack attachments.

These are the supplied pack quantities and cut lengths, not a requirement to use every piece on every sail.

For spares or custom lengths, choose 1.2mm lacing line on a 15m reel, 2.2mm corner-tie line on an 8m reel, or 3mm corner/bridle trimline on a 16m reel. Reel length is the total supplied, not the length of an individual tie.

For racing, the sail must remain within 10mm of the mast and boom at the relevant eyelets. Set the ties to your sailmaker’s guidance within the class limits.

8. Painter / towing line

A purpose-made floating painter is easier to recover from the water than a sinking general-purpose line. Keep it tidy and accessible so it can be deployed promptly.

Choose the 8.1m floating painter or our 8.1m spliced painter. Both Xtremity listings describe 6mm rope. Follow the individual listing for the supplied version.

The class minimum is a single buoyant rope of 5mm diameter and 8m length, secured to the mast thwart or mast step. Do not shorten a supplied painter without checking the resulting length.

9. Daggerboard hold-down bungy and its support line

The hold-down bungy applies tension around the daggerboard. If it has lost elasticity or its cover is damaged, replacing the assembly is often easier than trying to reuse worn parts.

The 1113 daggerboard bungy kit uses 6mm shockcord and includes tubing/handle components and 3mm Vectran support line. The support line is part of the bungy routing and must be renewed if worn. The arrangement also helps support the toe straps.

For replacing only the elastic, select the correct diameter from our 3–6mm shockcord range. Measure using the kit’s intended routing; replacing tired elastic with the same stretched length may leave the new system too slack. Set the tension so the sailor can still operate it comfortably.

10. Mast-retaining line

The mast needs an effective retention arrangement for a capsize. A working mast lock may fulfil this role; a boat using a retaining lanyard needs a sound line and sound attachment points.

For a rope-based arrangement, contact us about a suitable low-stretch line from our 3–4mm rope range. There is no universal length for every mast step, lock and thwart arrangement. Match the boatbuilder’s method and check that the line actually prevents the mast heel escaping, rather than merely keeping the mast loosely connected to the boat.

11. Toe-strap lashings and lifting elastic

Check both the load-bearing attachments and any elastic holding the straps up. These do different jobs.

• Load-bearing lashings: where the straps are rope-adjusted, replace with a suitable low-stretch line matched to the original arrangement. 3mm D12 78 is an option for existing designs using 3mm Dyneema. Other boats use fixed webbing and fittings rather than rope adjustment.
• Lifting elastic: use compatible shockcord where fitted, or the toe-strap support provided by the 1113 kit.

Length: measure each lashing for the intended strap height, number of turns and fastening. Lifting elastic must not replace a load-bearing attachment. Set both straps for the sailor’s feet and check adjustment ashore.

12. Bailer and paddle retaining lines

Each bailer and the paddle need their own secure hull attachment. Make the tethers long enough for use from the sailing position, without leaving excessive loose rope in the cockpit.

3mm polyester line is a practical option for simple tethers; compatible shockcord can be used where an elastic arrangement is intended. These are starting options to match to the fittings, not mandatory diameters.

Length: measure each piece individually. Let the sailor test the full bailing or paddling movement before trimming. Two bailers mean two secure attachments; do not rely on one item being tied only to the other.

13. Other small lines and attachments

• Whistle attachment: use the whistle/PFD’s intended short attachment; the whistle must be secure and accessible.
• Rudder retention: inspect the retaining clip. A tether does not replace the specified clip.
• Tiller-extension joint: any internal safety cord is part of the joint assembly. Replace a damaged joint with the correct part rather than treating it as a loose rigging line.
• Buoyancy-bag straps: these are webbing restraints, not ordinary rope lashings. Inspect the straps and their fittings when checking the rest of the boat.
• Optional equipment ties: use short, tidy attachments for permitted accessories. Small cordage can be useful, but do not add loops that obstruct the sailor or controls.

Choosing a rigging pack

School rigging pack — 1056
For EX1050 and EX1051 School spar sets. Contains a 6mm polyester vang, 5mm polyester halyard, 4mm polyester outhaul, 3mm Vectran bridle with ring and 3mm Vectran boom preventer. It does not replace the mainsheet, sail ties or hull safety lines.

Pro Line upgrade package — 1370
Upgrades the outhaul, vang and halyard. The specified package uses a 3.5mm outhaul, 3mm Dyneema vang primary with 5mm Technora/Dyneema secondary, and a halyard arrangement with a low-friction ring. It is a control-line upgrade, not a complete boat rope pack.

Building a full replacement order? Choose one mainsheet or mainsheet pack, the correct halyard and boom-control arrangement, sail ties, painter and the hull’s retention/tether lines. Check pack contents first to avoid buying the same primary or control line twice.

Need help with your setup?

Send us a photo of the line you are replacing, your spar make/model and the existing length. We can help identify the relevant rope or ready-made replacement.

Call 01489 573249 or email shop@xtremity.net.

Shop Optimist ropes and lines · Shop all Optimist equipment