Perhaps understanding what they are will help.
While not as popular as they once were, running backstays may still be a worthy addition to your rig.
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A running backstay is a removable stay that provides aft support to the mast from either the masthead or the point at which an inner forestay is attached. It originated as a response to the material…
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Running Backstays
Last Updated on Wed, 05 Oct 2022 |
Sail Technology
Running
backstays come in pairs, one to a side, and are not permanently fixed. Instead they can be eased off or removed on the leeward side when not in use. In most cases, running backstays will run from the aft weather side of the boat to a point on the mast usually two-thirds of the way up the spar. If the mast is sophisticated there might be two, or even three sets of running backstays on each side that can be independently adjusted. In this case the lower running backstays are called checkstays.
If
your boat is equipped with running backstays and checkstays, or "runners" as they are most commonly known, you can use them to arrest the bend of the mast instead of just having it bend of its own free will. Specifically, as you tighten the backstay the mast will only bend until the runner comes tight, at which point the spar will no longer bend. The runners can also be used to straighten the mast if doing so will help you achieve a desirable sail shape. Furthermore, in concert with the backstay they can be important in controlling the shape of a headsail since tension aft will apply tension to the forestay. This interplay between the backstay, runners, and forestay is important to overall sail trim. Note that by manipulating the backstay and runners you are not only controlling the amount of camber in the mainsail, you are also affecting its location, since as the mast bends and pulls shape from the sail, it pulls it from the front of the sail, with the result that the location of the maximum amount of camber moves further aft. In mainsails you want to keep the point of
maximum draft at roughly the midpoint of the sail, something you should always keep in mind when adjusting the other aspects of mainsail shape.
In recent years there has been a trend away from the running backstays that were so prevalent in the past. Before fabrics became really stable you needed to be able to manipulate sail shape in quite large measures, and bending masts was a good way of doing this. Having a mast that relied heavily on running backstays to keep it upright, however, was not something many sailors were keen on, so with the advent of newer sailmaking materials the trend has been toward fixed swept-back spreaders to support the mast without all that extra rigging. One drawback to these newer setups is that once the rigging is tight you are not able to bend the mast so much. Fortunately, with precise sail engineering, this is not the issue it used to be.
