Running backstays... Sails and Rigging- Standing and Running Forums

Scratch:

I have a PDF and JPG of a sketch of running backstay (provided by DE38 owner), detailing parts and connnections, but I can't upload right now because of  internet speed constraints. If you want, I should be able to attach it to an email an send it to you direct. Just email me at : de32@fairpoint.net / Duane Nealon

Below is running backstay overview that I had in my files that I found on the net.

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Running backstays may look and seem complicated but they're really not, particularly on a boat the size of yours. The concept behind these stays is that they allow you to control the upper portion of your mast, and therefore adjust the shape of that same area of the sail plan. Now using them properly depends upon a few things. I'm assuming that your boat is a fractional rig and therefore the designer added the running backs to help support the uppermost portion of the sail plan. In lighter winds, you may not need to use them at all. We used to have a set of running backs on an E-Scow that I sailed on, and we rarely used them in under 10 knots of wind.When the breeze comes on, so do the running backs. You'll need to spend some time experimenting with their use so that you know just how much adjustment you need given different wind conditions. What I recommend is that you pick an afternoon (preferably one with moderate winds, say 12 to 15 knots) and head out sailing with your normal crew. Once you've got the sails trimmed in and you're heading upwind, tension the running backstay on the weather side (with the leeward one loose) and then stand at the base of the mast and site up the spar to see what additional adjustment does to the mast and consequently the shape of the sails. Depending upon where the stays are fitted to the mast, tensioning them may also affect the tension of the headstay, so it's also important that you look at your headsail after you adjust the running backstays. These kinds of observations are the best way to learn about the use of the running backstays on your particular boat. Also, if your boat is fitted with a speed gauge, you can correlate that information as well to better understand the outcome of the adjustments you make with the backstays.Now, you ask about the potential of duplication with running backs and what most sailors refer to as the permanent backstay. What's involved here is really geometry. The running backs are usually attached somewhere below the masthead, so the force they exert on the spar is largely different than the force exerted by the permanent backstay, and thus the end result on the shape of the sail plan is slightly different as well. Also, running backstays aren't set in exactly the same plane (getting geometrical here) as the permanent, so they tend to exert a side force on the spar and thus the sail plan. That's another reason why it's critical to site up the mast and observe the changes made by adjusting the running backstay. After you've become more comfortable with the range of adjustment on your running backstays, you won't need to site up the spar. By that time, your eyes will be trained to see the changes in sail shape and that will become your gauge regarding the appropriate tension for the runners. One final word of caution. The improper use of running backstays has been known to get sailors in trouble. If you're out sailing in big breeze, say over 24 knots, and someone forgets to release the running backstay on a jibe, or worse yet, put tension on the new weatherside one, you could end up breaking the mast. So give yourself some time to learn these stays and their general use when the wind is moderate and you should be good to go.

I added running backs to Bodhran back in 2006 and have used them all of 3-4 times since.  The above theory is great for high performance fractional rig boats, but for Downeaster's the main reason to have running backs is to support the mast at the inner forestay when you're flying with just the staysail up.  In really heavy winds the staysail can start pumping the mast, bending it forward at the inner forestay attachment point.  Having a reefed main up provides enough tension to keep the mast from pumping, but when you go down to just a staysail, then it's nice to put on the running backs.  I've yet to see my mast actually do the pumping thing, but I've been out in 35+ with just the staysail up a few times and have always put the runners on.  If the wind's ahead of the beam, I normally have the trysail or double reefed main up.  Downwind is where I think the runners may be necessary.  The attachment point for the inner forestay on our boats is pretty high and may be supported well enough by the backstay so I'm not sure that they're really necessary.  Still it gives me a warm fuzzy to have them on when it's really snarly out.

I installed the Brion Toss cheap and chearful version of running backs.  I added t-bar fittings with eyes just above the inner forestay attachment to the mast.  I tied length's of 5/16" spetra to each and then leave them coiled on my pin rails when not in use.  When you need a running back, simply run the windward line through the windward genoa car slid back to the aft most position and then tension it with a winch.  Doing away with the traditional 4:1 tackle cuts way down on the expense and clutter.  Using a winch allows you to tension way beyond 4:1 if you need to in heavy winds.  Here's a pic of the T-bar toggle eyes on my mast:

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Jason Rose

DE32 Bodhran

This is a sketch that a DE38 owner (not sure who to credit) had provided.

The only thing I would change, or add to this design is that I would drill the mast for a 'compression tube' to accommodate the 3/8"SS through bolt. I might also recommend an additional aluminum pad to be machine screwed (or welded as is the mast spreader connection) on the outside of the mast to essentially double the 'meat' of the aluminum against where this through bolt bears. 

Also, I'm not sure I would use the deck track for this application. I've uncovered my deck track to rebed it. The factory installed backing plate is not that substantial. Also, if your boat's deck track has experienced any water intrussion over the years, the core may have been degraded or a degree of fiberglass delamination may be present in this high stress area. I'm not sure that the cap rail is the best connection either. Maybe beefing-up the bulwark for a backplated eyepad.

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