Collection: Field Notes - Regenerative Materials | 

Series: Natural Ropes |

Why how you handle, coil and store rope between uses matters as much as how you treat it

Caring for cordage: The rope locker problem

The rope that fails in spring is usually the rope that went into a locker in autumn. Not the rope that was overloaded, or chafed through, or left in seawater for a year without treatment. The ordinary rope, stowed at the end of a season without much thought, that comes out soft in a section or brittle at a splice and has to be replaced before the boat is fit to use.

I have made this mistake enough times in enough variations that I now think of the storage interval as the most consequential part of a rope's life — more consequential, in most practical situations, than the working loads it carries or the preservation treatment it has received. The mechanisms that destroy natural rope are all most active when the rope is not being used and not being attended to. Bacterial decay proceeds continuously in damp fibre. Salt crystals work into the bundle on each wet-dry cycle. A sealed locker in a temperate autumn is warm, damp, dark, and stagnant — nearly optimal conditions for the organisms responsible.

Atkins and Purser note this directly in the 1936 trials, almost in passing: ropes may become entirely useless while stored below decks, especially in tropical climates. The same process operates in a British boat locker over winter. Just more slowly, and more invisibly.

The salt problem and why rinsing ropes actually matters

There is a specific mechanism here worth understanding rather than simply accepting the instruction to rinse rope after use.

When seawater dries from rope fibre, sodium chloride crystallises throughout the bundle. Sodium chloride is hygroscopic — it absorbs water vapour from the air continuously, maintaining moisture levels within the fibre even when the rope's surface appears dry to the hand. A rope that feels dry in a boat's cabin may have 20–30% moisture content at its core, which is well above the threshold at which bacterial cellulase activity proceeds. The rope is not dry. It is salt-damp, which looks like dry but is not.

Fresh water rinsing before drying dissolves the deposited salt and removes it from the bundle. A rinsed rope, given adequate ventilation, can reach genuinely low moisture content. An unrinsed rope cannot, regardless of how long it is left, because the hygroscopic salt it retains continuously counteracts the drying. This is the reason rinsing is not optional maintenance but the step that makes drying effective.

I kept a pair of identically treated ropes through a winter — same fibre, same treatment date, stored in the same locker. One rinsed before stowing, one not. I did not run tensile tests in spring, which I now wish I had. But when I opened both along the length to check internal fibre condition, the unrinsed rope showed softening and some powdering in sections where the rinsed rope was intact. The difference was not catastrophic. It was also not subtle. One season, one locker, the only variable being a few minutes at a hose. The evidence is anecdotal and I hold it as such, but it is consistent with what the mechanism predicts.

The rinse needs to be more than surface-wetting. Run water through the rope at pressure — a hose rather than a bucket — and work it through your hands as you rinse to open the strands slightly and let water reach the interior. For larger diameter rope, coil it loosely and submerge it in a tub of fresh water for thirty minutes before hanging. The salt diffuses out into solution. Then dry.

Drying natural cordage

Warm, ventilated, out of direct sun is the target. Each of those qualifications matters separately.

Warm accelerates drying by raising the vapour pressure of water in the fibre and increasing the rate of evaporation into the surrounding air. A heated drying space in autumn — a workshop with a stove, a shed with a dehumidifier running — will bring rope to appropriate moisture content in two to three days for most diameters. Without heat, in a British October, the same process takes closer to two weeks, and in a damp shed it may not complete at all.

Ventilated matters because a sealed space quickly reaches equilibrium humidity, at which point evaporation from the rope slows or stops regardless of temperature. The rope needs moving air to carry moisture away. Through-ventilation — hatches open, a fan if available — is considerably more effective than simply leaving the rope in a closed space. A dehumidifier in a sealed rope locker is a more useful tool than a heater for the same reason: it removes moisture from the air directly rather than raising temperature and hoping the moisture goes somewhere.

Out of direct sun is the qualification that surprises people. Direct sunlight accelerates drying, which sounds useful, but UV exposure progressively degrades the lignin fraction of natural rope fibre — the hydrophobic component that provides inherent partial resistance to moisture uptake and bacterial access. For treated rope, sun volatilises the lighter fractions of Stockholm tar faster than necessary, shortening the effective life of the treatment. A shaded, well-ventilated space is meaningfully better than a sunny deck, even though it feels less intuitively correct.

For rope that will be treated before storage, the moisture content target before treatment application is 12–15% — the same threshold used for timber before oil application. Below this point the fibre absorbs treatment compounds properly rather than having them sit on a surface already partially occupied by water. The practical test is to hang rope in a dry, heated space for a week and assess whether it still feels cool to the touch on a warm day. A rope that has lived in a damp locker for a month is not ready to treat regardless of surface feel. Give it more time than you think it needs.

Coiling ropes

A three-strand laid rope is a twisted structure with inherent torque built into it. Right-laid rope — which is almost all three-strand natural rope — must be coiled clockwise. This is not convention for its own sake. It follows directly from the geometry.

The groove between strands in a right-laid rope follows a right-hand helix. Coiling the rope clockwise works with that geometry, allowing the rope to settle into a stable coil without accumulating twist. Coiling anti-clockwise works against the lay, inducing torque into the rope structure with each turn. Eventually this produces hockling — a loop that flips over on itself when the rope is put under tension, forming a kink that permanently damages the strand geometry at that point. The Handbook of Fibre Rope Technology discusses hockling as a failure mode associated with over-twisted or badly coiled laid rope, and the damage at a hockle point is structural rather than surface — the rope will fail preferentially there under load.

Smith is direct about this in The Marlinspike Sailor: right-laid rope is always coiled right-handed, clockwise. New rope often comes with a set from its manufacture that encourages it to kink rather than coil cleanly. The remedy is to coil it clockwise and allow it to settle, not to fight it by pulling or stretching. I have pulled rope trying to remove kinks, usually making them worse. The geometry wins.

The coil diameter relative to rope diameter also matters. Too tight a coil on large-diameter rope maintains a permanent bend at each turn, stressing the outer fibres of the strands. A rough guide: the coil diameter should be at least twenty times the rope diameter. A 20mm rope should not be coiled tighter than 400mm diameter. For storage over a season, larger is better.

Freshly tarred rope should not be coiled tightly until the treatment has cured — surfaces will stick together under the pressure of a tight coil and be difficult to open without tearing the treatment film. Hang it loosely in open loops for at least 48 hours first.

Storing natural cordage

The primary requirement is air movement. A dry, ventilated space — even an unheated one — is a better storage environment than a warm, sealed one. Rope lockers on most small boats are designed for convenience rather than rope health — sealed, with limited drainage and no through-ventilation, often near heat sources that create convection without air exchange. If the locker smells musty when opened, the rope inside is deteriorating regardless of how well it was prepared before going in.

The practical responses are limited. Ensure the locker has ventilation holes that are not blocked. Drain and dry the locker itself at the end of each season — the moisture in the space is as important as the moisture in the rope. Store coils hung rather than laid flat: a hanging coil breathes on all sides, while the bottom of a flat coil is in contact with whatever surface it rests on.

Keep natural rope away from acids, alkalis, and organic solvents. Battery acid spilled in a locker containing natural rope causes immediate and severe cellulose damage. Bleach vapour attacks cellulose. Fuel and solvent vapour degrades tar and linseed treatments by dissolving the lighter fractions. The battery box and the fuel tank are the wrong neighbourhood for natural fibre.

Store rope types separately. Treated rope in contact with untreated rope transfers treatment compounds unevenly and in ways you have not chosen. Tarred hemp alongside cotton decorative rope will deposit tar where you do not want it.

End of season

The end of a sailing season is where most of the decisions that determine next season's rope condition are made. The sequence matters.

Rinse while the rope is still wet from the last sail — doing it at this point is easier than doing it after salt has dried in, and the last sail is the last time it will be convenient until spring. Hang to dry thoroughly: in a British October this means a heated space or an extended run of dry weather, not a shed as temperatures drop through November. Once dry, open the rope along its length to check internal fibre condition before retreating. Treating rope that is already significantly degraded is work applied to a problem the treatment cannot solve. The internal powdering and yarn softening that indicate advanced deterioration are easier to find now, when you are looking, than in April when you are trying to get the boat in the water.

Then retreat, allow to cure, coil for storage. Check the end treatments while you have the rope in your hands — a whipping that has worked loose or a splice that is beginning to open is easier to deal with now than mid-season.

Rope that goes into winter storage in good condition, properly treated and coiled in a ventilated space, comes out in spring in essentially the same condition. The investment in autumn is an hour or two of attention. The alternative is discovering in March that rope you were counting on needs replacing before the boat is usable. I have made that discovery more than once. The rope that fails quietly in storage over winter is under no load, in no weather, doing nothing that should harm it. It fails because the interval was not attended to.

There is one small consolation in all of this that synthetic rope does not offer. Natural rope that has genuinely reached the end of its working life — that has been maintained, used well, and finally worn out — can be cut up and composted. It goes back to soil rather than to landfill, without the microplastic fragmentation that attends the end of life of synthetic cordage. The composting point is not a throwaway observation. It is part of the argument for why the maintenance is worth doing in the first place.

Sources: W.R.G. Atkins and J. Purser, The Preservation of Fibre Ropes for Use in Sea-Water, Journal of the Marine Biological Association of the United Kingdom (1936). H.A. McKenna, J.W.S. Hearle and N. O'Hear, Handbook of Fibre Rope Technology (Woodhead Publishing, 2004). Hervey Garrett Smith, The Marlinspike Sailor (International Marine, 1971).

At VAKA I design and test build skin-on-frame sailing craft in natural materials throughout — the rope that rigs and fends them follows the same maintenance logic as the hull: attend to it between uses, not only when something fails.

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