Tarp Ridgelines & Tensioners: Knots, Prusiks and the Right Height

What is a tarp ridgeline – and why does it matter?

The ridgeline is the backbone of a tarp shelter. It sets the height of the pitch, carries the weight of the fabric and holds the ridge seam straight so that rain runs off both sides instead of pooling in a belly. A tarp hung on a slack line can never be pitched tight, however hard you pull the guylines: the slack simply moves to the middle. That is why experienced campers spend more care on the ridgeline than on any other part of the pitch.

A complete tarp ridgeline has five parts: an anchor hitch on tree 1, a stretch of clean cord over the shelter, two prusik loops for the tarp’s ridge tie-outs, a tensioning hitch on tree 2 and two drip lines just outside the tarp ends. Each knot does one job, and the essential knots guide covers every one of them in detail. New to camp skills? Start with bushcraft basics.

Fixed vs. adjustable ridgelines

There are two basic ways to rig the line. A fixed ridgeline is tied off at both ends with ordinary knots, and you tension it by retying or by pulling the trucker’s tail again. An adjustable ridgeline carries its tensioner permanently: a pre-tied loop for a trucker’s hitch, a small mechanical line tensioner, or a toggle-locked slipped hitch, so you can tighten or slacken it in seconds without untying anything. Many campers pre-rig one end at home – a loop spliced or tied in, the prusiks already threaded – and only tie the second end in the field.

Either system works. Learn the fixed version first, because the knots are the same ones you need when something breaks or the trees are an awkward distance apart. Then pre-rig the line you carry, as described in the pre-rigging section of the knots guide.

Which cord for a tarp ridgeline? Diameter, stretch and length

The ideal ridgeline cord is 3–5 mm thick, low in stretch, easy to grip and 10–15 m long. Thinner cord saves weight but is hard on cold hands, cuts into bark and lets prusiks slip; thicker cord is heavy and bulky for the small loads a tarp creates. More important than diameter is how much the cord stretches, especially when it gets wet and cold.

• Nylon kernmantle cord (paracord type): strong, cheap and pleasant to handle, but elastic by design and noticeably stretchier when wet. It works, but expect to re-tension at night. Our paracord guide explains why nylon behaves like this.
• Braided polyester cord: stretches far less and takes up less water, so the line stays tight through rain. A very good all-round choice.
• High-modulus polyethylene (HMPE) cord: very light, very strong and with almost no stretch, but slippery. Knots such as the bowline or taut-line hitch can slip in it, so use hitches with extra turns and check them under load.
• Tarred bank line or natural fibre: grippy and cheap, fine for short-term lines, but weaker and, in natural fibres, prone to rot. Better for lashings and guylines than for a ridgeline that carries a wet tarp all night.

How long should a tarp ridgeline be?

Take the tree distance and add about 3 m: roughly 1.5 m at each end for the wraps, the hitch and the tail. With trees 5 m apart you need about 8 m of cord. A 10 m line covers tree spacings up to about 7 m; carry 15 m if you often camp in open woodland where suitable trees stand far apart. The tarp pitch and cordage planner uses the same rule and adds guylines and a 10 % reserve.

Ridgeline knots for tree 1: round turn, timber hitch or Siberian hitch

The first end of the ridgeline needs a hitch that holds under steady load and comes undone easily in the morning. Three ridgeline knots cover almost every situation. All three are taught step by step in the hitches section of the knots guide; the descriptions here match that guide.

Timber hitch – fast on a thick trunk

Pass the cord round the tree, take the working end round the standing part once, then twist it round its own part three to four times – five or more on smooth bark or slippery cord. Pull the standing part so the twists bite against the trunk. The timber hitch holds well while the line is under steady tension and falls apart almost by itself when you release it. Its weakness is a slack load: if the ridgeline goes loose in the night, check the timber hitch before you re-tension.

Siberian hitch – the quick-release start

The Siberian (Evenk) hitch is tied round your hand in a few seconds and released with a single pull on the slipped tail – ideal on cold mornings when your fingers do not want to pick at knots. It is good under load; push a small stick through the bight as a toggle when you want it extra secure, for example on a windy night or with slippery HMPE cord.

Tensioning the ridgeline: trucker’s hitch with a slippery finish

The second end is where the ridgeline gets tight. The classic answer is the trucker’s hitch: a loop in the standing part acts as a pulley wheel, giving a theoretical 3:1 advantage (friction reduces it in practice). With it, you can pull a ridgeline drum-tight with one hand, lock it, and release it in the morning with a single tug.

Why a slippery finish?

A “slippery” or slipped finish means the last half hitch is tied with a bight instead of the end, like the bow of a shoelace. Pull the tail and the hitch falls out. You will untie the tension end more often than any other knot – to lower the pitch, re-tension or pack up – and a slipped finish makes each a two-second pull. Leave the tail long enough to find in the dark, coiled and hung on the tree.

Alternatives to the trucker’s hitch

• Toggle-locked slipped hitch: pass the line round the tree, form a slipped half hitch round the standing part and push a small stick through the bight. Fast and releasable, but with no pulley advantage.
• Taut-line hitch: adjustable and familiar from guylines, but it tends to slip on slippery low-stretch cord. Fine on nylon and polyester, less so on HMPE. See tensioning knots.
• Small mechanical line tensioners: light aluminium or plastic pieces that lock the cord by friction. Quick and neat on a pre-rigged line; carry the knot as a backup in case one breaks.

Prusik loops on the tarp ridgeline: slide, centre and tension the tarp

A prusik tarp set-up hangs the tarp below the ridgeline on two short loops of thinner cord. Wrapped three times round the line, a prusik grips when it is loaded and slides freely when you take the load off. That gives you three advantages over tying the tarp straight to the line: you can centre the tarp exactly between the trees, you can stretch the ridge seam taut by pushing the prusiks outwards, and you can take the tarp off in the morning without touching either ridgeline knot.

The diameter rule: the loop must be noticeably thinner than the ridgeline – for example 2–3 mm loops on a 4–5 mm line. If the two cords are similar in size, the prusik will slip. On a very thin ridgeline, add a wrap rather than reaching for a thicker loop. Make four loops at once – two for the tarp and two spares for a lantern, a gear bag or a drip line – as described in the prusik section.

Over-the-line instead? You can simply drape the tarp over the ridgeline. It is quick and needs no prusiks, but you cannot tension the tarp along its length, and water running along the cord reaches the fabric at the ridge seam. The under-slung prusik method is the bushcraft standard for good reason. The tarp’s own tie-out layout matters here too: see tie-outs and attachment points.

How high should a tarp ridgeline be? Heights for common pitches

The ridgeline height depends on the pitch, the tarp width and the wall angle you want. For a ridge pitch such as the A-frame, each half of the tarp slopes from the ridge to the ground, so ridge height = (tarp width ÷ 2) × sin(angle). For a lean-to the whole width forms one slope: height = width × sin(angle). The tarp geometry section explains the formulas, and the tarp planner calculates them for your tarp.

Field check without a calculator: at 45° the ridge height equals the horizontal distance from the point under the ridge to the tarp edge. Measure both with a stick. A ridge higher than that distance means steeper walls, which shed rain better.

Level or slightly lower at the foot end. Never let the ridgeline drop towards your head end: water follows the line and the seam, and runs to the low end. Sight along the line from one tree before you hang the tarp.

No trees? Two trekking poles or straight dead sticks of about 1.2 m replace the trees for a low A-frame. Run the ridgeline over each pole top and on to a stake about 45° outwards along the ridge axis; the tension holds the poles upright. Good stakes matter more here than anywhere else – see tent pegs and stakes.

Re-tensioning when the cord gets wet

A ridgeline that was perfect at 5 p.m. can sag by midnight. Three things cause it: the cord stretches when it gets wet and cold (nylon much more than polyester), the knots bed in under load, and a wet tarp is heavier and stretches too. None of this is a fault – it is why the tension end is slipped and easy to reach.

How to re-tension without starting again

Pull the slipped tail of the trucker’s hitch to release the half hitches, keep a pinch on the crossing so the line does not run back, take in the slack through the loop and tie the slipped half hitches again. With a pre-rigged mechanical tensioner, just pull the tail through. Then slide the prusiks outwards until the ridge seam is straight once more. Do not try to cure a sagging ridgeline by pulling the prusiks apart: they will slip, and the seam stays slack in the middle.

Guylines follow the same logic. Tension the corners first, then the side tie-outs, using adjustable hitches you can reach without leaving your sleeping bag in a hurry. The routine for long wet nights is in camping in the rain, and camping in strong wind covers storm pitches; the wind and Beaufort calculator helps judge when to lower the line.

Protecting trees: wide straps instead of bare cord

Thin cord under tension acts like a saw on bark, especially when wind moves the tarp all night. It can damage the living layer beneath the bark that the tree needs to move water and nutrients. A ridgeline carries less load than a hammock, but the same courtesy applies: put a wide strap round the trunk and tie the ridgeline to the strap, or at least wrap a piece of fabric under the cord on soft or thin bark.

Choosing the trees is part of choosing the site: level, raised ground, no water channels and nothing overhead that can fall. The camp site selection guide shows how to read the canopy, and leave no trace explains why the strap matters even for one night. Hammock straps double as ridgeline straps; the hammock guide’s tree section covers sizes and soft-barked species.

Hammock ridgelines: tarp ridgeline vs. structural ridgeline

Hammock campers usually rig two different lines, and they are easy to confuse.

• The tarp ridgeline is a normal ridgeline between the same two trees, tied about 30 cm above the point where the hammock straps meet the trunks. It is independent of the hammock, so you can pitch the tarp first in rain and hang the hammock in the dry beneath it.
• The structural ridgeline is a short, fixed-length cord tied between the two ends of the hammock itself. It sets the same sag every night, regardless of how far apart the trees are or how high the straps go. As a rule of thumb it is about 83 % of the hammock’s length – for a 3.3 m hammock roughly 2.7 m.

The structural ridgeline should be a low-stretch cord, tied with fixed loops or adjustable through a friction hitch while you fine-tune it. It is not a load-bearing tarp line and should never carry the tarp: if it is pulled taut by your weight, it is too short. It is, however, the perfect rail for a bug net, a small organiser or a head torch on a prusik. All the hanging details – the 30° hang angle, strap heights and the diagonal lay – are in our guide on how to hang a hammock.

Common ridgeline mistakes and three practice drills

Most ridgeline problems come from a handful of habits. Catch them in the garden and they never cost you a wet night:

• Knots in the middle: keep the section over the shelter as clean cord, with all knots at the trees, so the prusiks can slide.
• Thin cord straight round bark: use a strap – for the tree, and because a strap stops the hitch sliding down a smooth trunk.
• Unslipped tension knot: a jammed hitch in frozen cord can take many minutes or a knife to undo.
• Prusik loops as thick as the ridgeline: they slip; thinner loops or an extra wrap fix it.
• Ridgeline in the path: a taut line at chest or neck height is a hazard at night. Hang a bright marker on it, especially in group camps.

Once the ridgeline is automatic, the rest of the tarp pitch is quick. Add a cord repair to your kit – a spare 3 m line and two spare prusiks weigh almost nothing – and see the repair kit guide for what else to carry. The knot finder suggests a hitch when the trees, cord or weather do not match the textbook.