View Full Version : running back stay
01-11-2005, 05:28 PM
I know almost nothing about running back stays on small boats. Would like to learn and none of my books go into any detail .. like design, installatin and use. Any suggestions? Thanks in advance
They can be used for a number of different reasons. On many small gaff boats the boom is so long that a fixed backstay isn't possible, and you use the two running backs to tension the rig and keep it from falling forward. This is especially true going down wind.
On other boats you may have a fixed backstay, but also have running backs. Often on a fractionally rigged (the forestay doesn’t go to the top of the mast) boat this is the only way to tension the forestay for going up wind. Many older wooden boats had tapered masts so that pulling on the backstay would only bend the top half of the mast.
Folkboats for one had diamond stays that went from the top of the mast down so that you didn't need running backs, but you could still get tension on the forestay...and have a flexible top section of the mast so that the sail would de-power in a blow. Many modern catamarans use this system and it works well.
I'm being brief in my explanation, and I'm sure others will follow with more details and reasons for using them.
01-11-2005, 05:45 PM
The unloaded or lightly loaded mast must be able to stand up without the runners set. The runners' real function is to counter a jib or forestaysail stay that's not supported by anything else. (Sometimes this job can be more expediently handled by jumpers.)
Gaff sloops may have runners as there is no way to set up a fixed back stay. But depending on how the rig is laid out, you may find that the pressure of the peak hallyard adequately tensions the jib stay and you don't really need runners, given the mast's strength and all. Or you may need the runners on a heavy gaff rig to counter the forward thrust of the gaff itself.
On modern rigs the use of runners is so different that they are not often called running back stays - more often called check stays. They are used to help control the mast bend. For example, hard on the wind in a good breeze you might crank in the back stay and forestaysail stay to give the mest some bend and use the check stay to keep the mast from pumping or even collapsing with that bend.
01-12-2005, 09:39 PM
Running backstays are a racing boat feature - they allow forestay tension to be maintained by helping support the mast that is too slender and weak to maintain the tension by itself. They are a bother, and a little scary when it's blowing and you realize without them the mast could go over the side. It encourages you to pay attention. But you get used to them and when your next boat doesn't have them you forget you ever had them.
The boat on which I learned to sail (a wooden Dragon class Olympic racer) had runners so I thought it was just part of sailing - I didn't really notice that all those other boats didn't have runners. It's true that those other boats looked like floating refrigerators, or worse: like sneakers someone left in the water by mistake. And that genoa of ours set perfectly every time even though we didn't really know why. We thought every genoa set that well.
01-13-2005, 06:06 AM
I have a gaff cutter and she has running backstays.
It might be amusing if I set down the terminology applicable to this part of the rig on an English gaff cutter:
The wires that go to the top of the topmast from the sides of the boat are usually called topmast shrouds, but according to Claud Worth in "Yacht Cruising" this is incorrect and they should be called topmast backstays, because topmast shrouds are always set from a top (cf "Master and Commander", &c!)
I mention this because this is why you never see reference to "topmast backstays" when discussing backstays!
Now, a gaff cutter with a topmast, or a large Bermudian cutter such as a J class, has
two sets of running backstays.
One set are called the runners, and they are set up to the lowermast head or about in line with the forestay, the pull of which they oppose.
The other set are called the preventer backstays, and these are set up to the topmast head.
Both have two parts - the wire attached to the mast, which is called the pendant, and the tackle attached to the deck, called the fall. The pendant is obviously a fixed length whilst the fall obviously is not!
You can replace the fall tackle with a Highfield, Giles or Warrington Smyth lever, but the flexible wire going to the lever will still be the fall.
It is possible to minimise the need for running backstays if the aftermost pair of shrouds are led well aft, in which case they are called swifters.
However, in my view, on a gaff cutter of even moderate size, it is wise to keep the weather backstay set up in a seaway because it takes the pitching loads off the masthead.
There is never any need to set up the preventers unless and until a jib topsail is set, or a topsail is set on a run or broad reach.
I hope all is clear now, marks will be awarded out of 10... ;)
01-13-2005, 06:39 AM
Like Andrew said (I can only provide some pics - without preventer of course)...
01-13-2005, 08:07 AM
Running back stays? You don't need no stinkin' running back stays! Rake your mast, and off you go! :D
01-13-2005, 09:27 AM
Jim, what kind of boat are you talking about? I have a Star with double running back stays, and I have a Dragon with a single runner and a permanant backstay. to give you any real insight we need to know what kind of boat you want to do this on.
01-13-2005, 12:27 PM
Re: mast staying up without them. I once had a short time at the helm of an America's Cup boat, and was busy showing how quickly and smoothly I could tack the thing. Then the skipper asked me to tack more slowly. I forgot that on the AC boats there is no backstay, only runners, and a misstep does in fact send the mast over the side. Makes for an interesting gybe.
01-14-2005, 02:03 PM
Mickey .. the boat is Ed Davis' Tropic Bird (WB#163). A surf dory rigged for both sailing and pulling
01-14-2005, 02:14 PM
More on the Tropic Bird design:
You might try contacting Andy Oldman to see if backstays are useful on the boat.
[ 01-14-2005, 03:17 PM: Message edited by: rbgarr ]
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