Running Backstays Attachment Points

[Weyalan]

My understanding is as follows:

The angle of the running backstay and the angle of the inner forestay are completely independent of each other. You do not need to worry about your inner forestay when locating your running backstay (except insofar as the attachment points of both, on the mast should be close).

As has been mentioned above, the main function of running backstays are to counteract the load applied to the mast by the headsail - i.e. the forestay trys to pull the mast forward, and the running backstays prevent this by pulling the mast aft.

Ideally, the fruther aft you can locate the runner attachment point to the hull/deck the better. The reason is that the further aft this point is located, the greater the component of the backstay load pulling the mast aft, as opposed to compressing the mast. If the runner was attached right at the base of the mast, all the runner load would be compressing the mast, and none would be pulling it aft. As you move the point aftwards, the component pulling aft increases and the compression load decreases. Ideally, if you had an infinitely long boat and the fixed point was at the transom, the load would become all pulling aft, and none would be compressive (but the marina fees would suck)

So, in summary, locate your fixed point for your running backstays as far aft as possible - preferably right at the transom. You are going to need a purchase system anyway to get any decent load on your runners, so you can, with judicious location of turning blocks, route your runner tail to wherever is convenient.

[Weyalan]

Here is the backstay, running backstay and checkstay arrangement on Insatiable:


The running backstays oppose the forestay loads. The backstay and checkstays are for shaping the mast (the checkstays also prevent mast pumping on what is a rather skinny mast section)

[Weyalan]

Not wishing to hijack, but the above is for a fractional rig. If you have a masthead rig with an inner forestay, then the the running backstays are, essentially checkstays that (a) oppose the loads of the inner forestay, and (b) allow a degree of mast shaping. Again, further aft is better (for the same reason as previously stated)

[silverp40]

Thanks Weyalan. The forestay is mast top so the running back stays counteract the forward pull of the inner forestay. I do agree that a more aft location reduces mast compression and puts more effort on the aft pull component. Unfortunately I cannot connect them on the transom (as in your boat) because there is a fixed bimini top over the cockpit. So, they will be as far back as possible, about 15" from the transom.

I was also contemplating the idea of doing without the 4 part tackle with cam that we presently have and just using rope clutches. The tensioning on the backstays could be easily done with one of the primaries?? The rbs are too short now and need new ones that are longer (with the relocation and all...)

What is your opinion on that?

[tdw]

Originally Posted by silverp40

Thanks Weyalan. The forestay is mast top so the running back stays counteract the forward pull of the inner forestay. I do agree that a more aft location reduces mast compression and puts more effort on the aft pull component. Unfortunately I cannot connect them on the transom (as in your boat) because there is a fixed bimini top over the cockpit. So, they will be as far back as possible, about 15" from the transom.

I was also contemplating the idea of doing without the 4 part tackle with cam that we presently have and just using rope clutches. The tensioning on the backstays could be easily done with one of the primaries?? The rbs are too short now and need new ones that are longer (with the relocation and all...)

What is your opinion on that?

Thats pretty much what we do. Our two aft most sheet winches are used for spinnaker sheets and the runners cos it would a very rare occasion were we'd want to you both at the same time.

Question.......do you sail the the Pearson as a cutter ? Our old girl is a sloop with removeable inner forestay on which we would fly a storm jib. We don't carry sail there as a matter of course.

[Weyalan]

Ok - so masthead rig with inner forestay and runing backstays (checkstays) to oppose the inner forestay - I got it!

In this case, getting a whole heap of load on these stays is not so important because you aren't trying to "tune" the mast, merely support it.

I have seen rope clutches used, as you describe, on a couple of late 80's style Farr 37s - that seems to work just fine. Just bear in mind, though, if you use a winch to grind on any significant runner load, you really ought to use the winch to take up the load before you release the rope clutch, otherwise you risk damage to the cover on your runner tail, shortening it's useful life significantly.

[Doodles]

Originally Posted by Weyalan

Ok - so masthead rig with inner forestay and runing backstays (checkstays) to oppose the inner forestay - I got it!

In this case, getting a whole heap of load on these stays is not so important because you aren't trying to "tune" the mast, merely support it.

I have seen rope clutches used, as you describe, on a couple of late 80's style Farr 37s - that seems to work just fine. Just bear in mind, though, if you use a winch to grind on any significant runner load, you really ought to use the winch to take up the load before you release the rope clutch, otherwise you risk damage to the cover on your runner tail, shortening it's useful life significantly.

This describes the setup on our Pretorian ... fixed backstay and two running backstay or to use the more correct term (thanks) "checkstays" or just "runners". The runners pass through a block on deck and then through a rope clutch to the winch. The boat is very new to us and I haven't had much chance to use the runners so far, but I appreciate the advice about taking up the load before releasing the clutch.

[silverp40]

Thanks also for the advice on releasing the load before disengaging the clutch..


To tdw:

Yes we sail her as a cutter but only on longer trips not daysails. The staysail works well on a beam reach and a bit deeper too. It adds sail area and fills in the slot behind the jib. Just got another saysail this one a deck sweeper that goes past the mast but have not tried it out yet. I suspect it would work for beating when the foresail is overpowered. We'll have to see though.

Otherwise the staysail is fairly high cut and heavily built and can be used for heavy weather too. It's also has one reef.

The inner forestay is removable(or easier relocateable), which is great for short tacking.

[tdw]

Originally Posted by silverp40

Thanks also for the advice on releasing the load before disengaging the clutch..


To tdw:

Yes we sail her as a cutter but only on longer trips not daysails. The staysail works well on a beam reach and a bit deeper too. It adds sail area and fills in the slot behind the jib. Just got another saysail this one a deck sweeper that goes past the mast but have not tried it out yet. I suspect it would work for beating when the foresail is overpowered. We'll have to see though.

Otherwise the staysail is fairly high cut and heavily built and can be used for heavy weather too. It's also has one reef.

The inner forestay is removable(or easier relocateable), which is great for short tacking.

Cheers.

There was a reason I asked that question but in the cold light of day..errr....ummm....I forget what it was....

Something to do with allocation I'd reckon but that would not apply if staysail is self tacking .

[silverp40]

-------There was a reason I asked that question but in the cold light of day..errr....ummm....I forget what it was....

Something to do with allocation I'd reckon but that would not apply if staysail is self tacking . ------

Our staysail is not self tacking as I really dislike the club foot(or something along those lines called) staysails. We tack it like the jib more or less (and release the leeward running backstay afterwards if we remember) . But we don't use it for short tacking/trips, mainly for longer trips where there is not a whole lot of tacking/jibing.

Well I guess that would be it, hope that answers your question?

[Jim Cate]

G'Day All,

Another data point:

On Insatiable II (not to be confused with Weyalans imposter Insatiable) we have a fractional rig with swept-back spreaders, a light permanent stay to the top of the mast and runners to support the forestay loads. Whole lot is a big PITA for a short handed cruising boat, but the performance is great. The runners are spectra with a three part tackle leading through Lewmar clutches to the secondaries for tensioning, and are used in all conditions save light airs. We routinely dump the Lewmar clutches with the full runner load on them, and after 37K miles there is no unusual wear on the tails. Other type clutches (Spinlocks in particular) simply would not release under load, so the issue of excessive wear is moot!

I'll add my strong advice to be sure that wherever you place the bottom of the runners the boom can not hit one in an accidental gybe. The sail hitting the runner might break a batten (we've done this) or even tear the sail (unlikely IMO), but if the boom should strike the runner the whole rig is at risk. Not a good thing!

In our case when we have two reefs in the whole sail clears the runners, so that in heavy conditions we can leave both runners set. This not only supports the mast extra well, but means we don't have to fuss with tacking the runners -- a big reduction in effort in trying conditions. Realistically, we often put in that second reef when at sea just to ease the crew work load... couple of lazy sods we are, Ann and I!

Cheers,

Jim and Ann s/v Insatiable II lying Hook Island, Qld, Oz northbound

[silverp40]

Thanks for the input Jim

It's tough to place the runners here so that they clear the boom as the runners go up to the 2nd spreaders and with the whole main up, the top of the main will get them in an accidental jibe...The bottom of the boom clears the runners so no hard contact but could break a break a batten...

I am just curious, if the boom should strike the runners is an accidental jibe hard enough to break the runner, would it not be better to break the rb rather than other things such as a gooseneck( that might loose the whole boom)?

Regards
Ovi

[deluxe68]

Originally Posted by svHyLyte

You are correct although the terms are sometimes used interchangably. On our yacht our runners are connected to the mast just below the upper spreaders and just below the point where our spinnaker poll lifts exit the face of the mast. Ours is an IOR era boat with in-line shrouds and the runners are used to stabilize the mast and prevent "pumping", a function that would be performed by fore'n aft lowers if they were fitted. Hence our runners are properly, Check-Stays as they "check" mast displacement out of column (necessarily "bend") that could lead to Euler Buckling.

Our runners were originally wire rope connected to 4-part tackles with the upper ("Koch") Block at about boom level. We replaced the wire with Spectra line and did away with the tackles in favor of single turning blocks attached to the Spinnaker Pad Eyes that lead the runner tails to #43 secondaries. We really only use the runners when the yacht is hard pressed or we can feel the mast pumping. In any case, however, check-stays or back-stays, the further aft the better in terms of stabilizing the mast and/or tightening a fore-stay.

FWIW...

We are looking at a First 42 in San Francisco that has the check-stays, the salesman told us they were running backstays. If these are just used for mast bending could they be eliminated for casual cruising? Or would it take a different mast to eliminate them?

[silverp40]

Qoute

If these are just used for mast bending could they be eliminated for casual cruising?


The running backstays are usually used for supporting a loaded staysail, such as a storm jib and keeping the section of mast from bending forward. If you are not planning on getting caught by heavy weather, they could be eliminated (if they are not part of the permanent rig).