Running Backstays
Managing the backstays that support the mast from behind and must be swapped on every tack and gybe
Why Running Backstays Exist
On a fractional rig, the forestay attaches to the mast somewhere below the masthead — typically at 7/8 or 15/16 of the mast height. The permanent backstay, however, attaches at the very top. This means the section of mast between the forestay attachment and the backstay attachment has no aft support. Under the forward pull of the forestay and the compression of the rig, this unsupported section can bow forward or pump in a seaway. Running backstays solve this by attaching at or near the forestay height and running aft to the quarters, providing the missing aft support for that critical section.
Runners do more than just hold the mast up. They give you direct control of forestay tension independent of the permanent backstay. On a masthead rig, the backstay and forestay are directly opposed — tightening one tightens the other. On a fractional rig with runners, the runner tension controls forestay tension at the forestay attachment point, while the backstay controls the masthead. This separation of controls allows much more precise management of forestay sag and, by extension, headsail shape.
Not every boat needs runners all the time. Some fractional rigs are designed with enough mast section stiffness and swept-back spreaders to sail upwind without runners in moderate conditions, relying on them only in heavy weather when the loads climb and the mast needs maximum support. Other boats — particularly racing designs with thin, bendy mast sections — need runners loaded for all upwind work. Your boat's designer and rigger will specify when runners are required.
Runners also appear on masthead rigs with an inner forestay (babystay or staysail stay). The inner forestay pulls the mast forward at a point below the masthead, and a runner opposes that pull from aft. Without the runner, setting the inner forestay would induce a forward bend in the mast that could be difficult to control. On cutter-rigged cruising boats, the runner is essential whenever the staysail is set.
Never release both running backstays simultaneously, even briefly. The mast section they support is structurally dependent on them — an unsupported mast in a seaway can pump and fatigue, or fail catastrophically in a gust.
Why do fractional rigs need running backstays?
On a masthead cutter rig, what does the running backstay oppose?
Types of Runner Systems
The hardware that tensions and releases running backstays varies from simple to sophisticated, and the choice depends on the boat's size, crew, and intended use. Every system must solve the same problem: apply high tension quickly on the new windward side and release it quickly on the new leeward side during every tack and gybe.
The Highfield lever is the simplest mechanical solution. It is a lever arm that tensions a wire runner to a preset load in one motion — flip the lever up to tension, flip it down to release. Highfield levers are fast, reliable, and require minimal crew skill. The limitation is that they provide only one tension setting, determined by the wire length and lever geometry. You cannot fine-tune tension for different conditions without physically adjusting the wire length at the toggle. They are common on cruising boats and older racing designs where simplicity outweighs adjustability.
Cascade tackle systems use a rope purchase — typically 6:1 to 12:1 mechanical advantage — to tension the runner. The tail is cleated when loaded. This provides full adjustability: you can set any tension from light to maximum, and change it instantly as conditions shift. The trade-off is more crew work and time on each tack. A crew member must physically haul and cleat the purchase, and release it cleanly on the other side. On shorthanded boats, this can be demanding. Line material matters here: Dyneema/Spectra lines are popular for cascade systems because they are light, thin for their strength, and have virtually no stretch — critical when you need precise forestay tension control.
Hydraulic runners are the most powerful and easiest to adjust under load. A hydraulic ram tensions the runner at the push of a button or turn of a valve, applying enormous force smoothly and precisely. They can be adjusted in increments while loaded — something that is nearly impossible with a cascade system under heavy tension. The drawbacks are cost, weight, and complexity. Hydraulic systems need maintenance, are susceptible to leaks, and add significant weight at the stern quarters. They are found primarily on grand prix racing boats and large performance cruisers. Some boats use a checkstay arrangement where the runners lead to the middle of the boat rather than the quarters, which reduces the geometric complexity during tacks — the boom is less likely to catch the runner.
If you are upgrading to Dyneema runners, be aware that Dyneema does not hold in standard cam cleats as reliably as polyester — its smooth, low-friction surface can slip. Use cleats specifically rated for Dyneema, or wrap the loaded section with a sacrificial cover.
What is the primary limitation of a Highfield lever system for running backstays?
Why is Dyneema/Spectra a popular line choice for cascade runner systems?
Handling Technique
The central challenge of running backstays is that they must be swapped on every tack and gybe. The windward runner is loaded (supporting the mast), and the leeward runner must be slack (otherwise the boom or mainsail hits it). When the boat changes tacks, the roles reverse. Timing and coordination are everything — a botched runner swap can mean a broken mast, a fouled boom, or a dangerous situation in heavy air.
The tacking procedure follows a consistent sequence. The helmsman calls "ready to tack." The runner crew on the new windward side takes up all slack on the new runner purchase or positions the Highfield lever. The helmsman calls "tacking" (or "helm's alee") and puts the helm over. As the bow passes through the wind and the boom begins to cross, the new windward runner is loaded — hauled and cleated on a cascade, or lever flipped on a Highfield. Simultaneously, the old windward runner (now leeward) is released. The timing window is narrow: the new runner must be loaded before the sails fill on the new tack, and the old runner must be released before the boom reaches it.
The consequences of poor timing are real. A late release on the old side means the boom swings into the loaded runner — at minimum, this stops the tack dead and backs the mainsail; at worst, it can break the boom or runner attachment. A premature release on the old side, before the new runner is loaded, leaves the mast momentarily unsupported. In moderate conditions this brief gap may be tolerable, but in heavy air with a seaway, even a second of unsupported mast can allow a dangerous pump or bend. With practice, the swap becomes reflexive — experienced crews execute it without conscious thought, and the boat loses almost no speed through tacks.
Gybing with runners presents the opposite geometry. The boom swings from one side to the other on a downwind course. The procedure reverses: load the new windward runner as the boom comes across, release the old one. The challenge during gybes is that the boom sweeps a wider arc and moves faster than during a tack, so the timing is tighter. On boats that run with the boom well forward, the leeward runner may need to be partially eased even before the gybe to clear the boom. Communication between helmsman and runner crew is paramount — call every step clearly.
Before a race or passage, practice the runner swap in moderate conditions until it is automatic. Start with slow tacks — the helmsman turns deliberately, giving the crew extra time. The crew calls 'new runner ready' before the tack begins. As the helm goes over, the crew loads the new runner and releases the old one, calling 'runners set' when complete. Gradually increase tacking speed. Time each swap. A well-drilled two-person crew on a cascade system should complete the swap in under 4 seconds. On a Highfield lever system, under 2 seconds. If you find the crew consistently late on the release, shorten the delay between 'helm's alee' and the boom crossing by tacking more slowly until the timing clicks.
During a tack, what is the consequence of releasing the old windward runner too late?
What is the correct timing for loading the new windward runner during a tack?
Tuning with Runners
Beyond their structural role, running backstays are a powerful sail-shaping tool. Runner tension directly controls forestay sag — the degree to which the forestay bows to leeward under the load of the headsail. More runner tension equals tighter forestay equals flatter headsail. Less runner tension allows more sag, which deepens the headsail. This gives you a direct, immediate control over headsail power that works independently of the backstay.
In moderate upwind conditions (10-16 knots), set the runners to produce a moderately tight forestay. The headsail should have noticeable depth — around 12-14% of the chord — with a smooth, full shape that generates strong drive without excessive heel. Sight up the forestay from the bow: it should have a slight, even curve to leeward, not a dramatic sag or a ruler-straight line.
In heavy air (18+ knots upwind), tension the runners to maximum. The goal is minimum forestay sag, producing the flattest possible headsail. Combined with maximum backstay tension, this is your primary upwind depowering system for the headsail. The flat headsail generates less heeling force, the boat stands up, and the helm lightens. Watch the jib telltales — if the inner telltales are stalling consistently even with good sheet tension, the headsail may be too flat, and you can ease the runner a fraction to restore some depth.
On a reach, runners are typically eased to allow the forestay to sag and the headsail to fill with more depth. Reaching requires power, and a deep headsail generates more drive on these angles. When running downwind, runners should be eased completely — the boom needs to go out to near-perpendicular, and a loaded windward runner restricts boom travel and risks the boom hitting the runner during an accidental gybe. Some experienced sailors leave the windward runner on a light preset tension even when reaching, providing some mast support without restricting the boom. This is a judgment call that depends on sea state, wind strength, and how much the mast section relies on the runners for stability.
Sight up the forestay from the bow periodically to assess sag. A straight or nearly straight forestay in heavy air means the runners and backstay are doing their job. A forestay with a deep curve to leeward indicates the runners need more tension — the headsail is deeper than intended and generating excess heel.
You are sailing upwind in 22 knots and the boat is overpowered with excessive heel. What should you do with the runners?
When running downwind, why should the runners be eased?
Summary
Running backstays support the mast section between the forestay and backstay on fractional rigs, and oppose the inner forestay on cutter rigs — they are structural necessities, not optional.
Runner systems range from simple Highfield levers (one tension, fast swap) to cascade tackles (adjustable, more crew work) to hydraulic rams (maximum power and adjustability at high cost).
The runner swap during tacks and gybes must be precise: load the new windward runner as the boom crosses, release the old one simultaneously. Late release fouls the boom; premature release leaves the mast unsupported.
Runner tension directly controls forestay sag and headsail shape — more tension for a flatter headsail in heavy air, less tension for a deeper headsail in light air and on reaches.
Never release both runners at the same time. The mast section they support depends on at least one runner being loaded at all times when sailing.
Key Terms
- Running backstay
- A stay running from the mast (at or near forestay height) aft to the quarters, providing aft support for the mast section the permanent backstay cannot reach
- Highfield lever
- A mechanical lever that tensions a wire runner to a preset load in one motion — fast and simple but not adjustable without modifying wire length
- Forestay tension
- The tension in the forestay, controlled by backstay and runners, which determines forestay sag and therefore headsail depth and shape
- Fractional rig
- A rig where the forestay attaches below the masthead, creating a section of mast above the forestay that is unsupported without runners
- Cascade tackle
- A multi-purchase rope system (typically 6:1 to 12:1) used to tension runners with full adjustability, at the cost of more crew effort
- Runners
- Shorthand for running backstays — the stays that must be swapped from loaded to slack on each tack and gybe