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-   -   Running Backstay setup (http://www.briontoss.com/spartalk/showthread.php?t=1863)

amkaplan 04-25-2009 05:12 PM

Running Backstay setup
 
I've got a Baba 40 with a cutter/ketch rig, and would like to get the running backstays on the main mast set up. The runners on the mizzen are fiddle blocks with a cam cleat that clip to padeyes by the cockpit. I figured that I would rig a similar configuration to another pair of padeyes I have, seemingly for the purpose.

In looking back through SparTalk archives I see that most threads consider running the runners back to a windward winch. Is this really necessary? Wouldn't the fiddles/cam cleat idea (similar to a boom vang) be adequate? I spoke to a Harken guy recommended by Bob Perry who suggested using Harken Mid-Range Classic blocks 1559/1564 with a SWL of 1800 lbs as being fine. With that recommendation in the hopper, I'm interested in opinions regarding the "boom vang" version as well as the degree of beefiness of the hardware needed.

Opinions, please?

Many thanks,

Allan

Brian Duff 04-26-2009 07:14 AM

Running Backstays, their effectiveness and use, are a function both of the power available to control them AND the ability of the mast section (and the way it is tuned static) being able to allow the runners to control the mast.

IIRC you have a big Ketch with two headsails, the inner staysail being the one which you desire to support with these runners? When setting up runners to control the tension on the inner forestay, a great amount of power is needed - on your boat I THINK that a 1:1 runner to your weather genoa winch, which is probably a 46:1, would be effective. Be sure the mast is tuned with some prebend, such that once you apply the runners you do not invert the mast section and ruin mainsail shape. On bigger boats i suggest a 2:1 before hitting the weather genoa winch, anyway.

While most boats come stock with 4:1 runner tackles, and while this may be effective purchase for a 28-32' boat, that doesn't mean that 4:1 is the best choice, or even suitable for bigger boats. We have modified many 45'-65' boats that came with 4:1 runners that were not effective. While these runners will indeed prevent the mast section from buckling under staysail stay loads, 4:1 will not allow you to add inner forstay tension or control that forestay for wind conditions. of course, you could lead that tackle to the winch, but then you have two problems - its REALLY difficutl to get the line out of the cam cleat on the lower block unless you relead it and apply load again AND now you have way excessive purchase, be careful not to break anything!

4:1 tackles are much more difficult to work with underway than a 1:1 or 2:1 runner with retractor, the 4 part purchase doens't haul in or easy out of the way of boom easily, the upper block and tackle gives the system a lot of weight which means it needs to me kept under control on the leeward side so people and boat parts don't get hurt, in order to retract that system someone needs to unshackle the bottom block and walk it forward to the shrouds then tension the system again, what PITA.

Save the weight, the expense, wear and tear on the boat and the hassel under way cut the block and tackle and just run your runners from that un-used windward winch!

Auspicious 04-26-2009 08:20 AM

I have wire runners with a 4:1 tackle near the bottom on my Hallberg-Rassy 40. The inner forestay is removable.

To get any reasonable tension on the inner forestay I have to crank down as hard as I can on the forestay clip and then tension the appropriate runner.

When tacking I have not had to move the leeward runner back to the shroud; easing it a good bit keeps it away from the boom and the main sail. Whether you can do that or not depends on how long your boom is, how much roach you carry, and where you land the runners.

Once set up, I have found the runners contribute to pointing higher when flying only the staysail.

sail fast, dave
S/V Auspicious

amkaplan 04-26-2009 11:30 AM

Brian,

Thanks for this explanation. I don't know how big I'd consider a 40' ketch, but yes, the runners are for balancing the inner forestay.

I think I follow your reasoning, at least for the 1:1 runner. Essentially, do you just use a length of line through a snatch block back to the winch? When off-wind, what happens with the runner -- doesn't it need to be kept out of the way somehow so it doesn't flail around and chafe? With a 2:1, don't you run into the same hassle of stowing the runner forward as the 4:1, except that you've got smaller tackle to deal with? Or, are you somehow rigging the 2:1 on the genoa track? I don't understand how you avoid stowing something forward in any case.

And what sort of line are you using for the 1:1, double-braid or Dyneema/etc.?

Thanks,

Allan

Brian Duff 04-27-2009 05:37 AM

with both 1:1 and 2:1 we use retractor lines lead through a block at the aft lower chainplate. all runner rigging is set up permenant.

gotta go rig boats npw, catch up with you all later on in the week!

Brion Toss 04-27-2009 09:40 AM

Power
 
Hello,
I'm emphatically with Brian on this one; on the mizzen, all the runners do is to keep the head of the mast from popping forward in a chop, or from the minor strain of a mizzen stays'l. On the main you are expecting them to do for the forestay what the backstay does for the jibstay. You probably would never even consider having a mere 4:1 purchase on the backstay, right?
Taking the line to the winch gives you the appropriate power, BUT please remember that the turning block (and its padeye) will take something like 150% of the runner load. A snatch block is extremely unlikely to be up to this, and the erratic nature of the loads won't be kind to it either. You don't want to be installing a missile here, so land herky, dedicated blocks, scaled to the load.
Fair leads,
Brion Toss

Auspicious 04-28-2009 07:08 AM

From a sailing point of you, think about how you will use your winches on each tack and how you will get from one to the other. Make sure you have enough and lines lead fair to primaries and--if you have them--secondaries.

We ran out of winches on a Beneteau 50 and ended up with the spinnaker flying from the masthead otherwise unsupported. It was quite a night, and a wonderful bar story. Not so good at the time.

hnoor0077 04-27-2016 09:20 PM

thank for sharing this
I'm emphatically with Brian on this one; on the mizzen, all the runners do is to keep the head of the mast from popping forward in a chop, or from the minor strain of a mizzen stays'l. On the main you are expecting them to do for the forestay what the backstay does for the jibstay. You probably would never even consider having a mere 4:1 purchase on the backstay, right?????

FecklessDolphin 05-21-2016 09:28 AM

If I read Brian's post correctly, he is advocating for a running backstay system composed of a single Dyneema line led to a block on the aft quarter and then to a secondary winch. Prior to reading this, everyone had steered me toward a 4:1 system with fiddle blocks. I like the idea of keeping fiddle blocks out of the air above my head. It also gives me another excuse to get secondary winches. The problem is that I do not have a spot for a rope clutch so that on port tack my secondary winch could not be used to reef my jib because the running backs would be using it. I have a new to me Morris Justine that I plan to sail offshore. Running backstays have been highly recommended. I have a thick mast (Metal Mast) with double lowers.

Brion Toss 05-24-2016 08:37 AM

Runners
 
Hello,
If I understand you aright, you want a rope clutch on the starboard side, so you can reef the jib, but there is no space for a clutch. First, on a boat that size, a cam cleat should be plenty to belay the furling line. Second, do you really need a winch to reef that jib? Optimal lead blocks, intermediate blocks, ratchet block aft, rig tune, etc. should make for minimal furling effort.Third, you don't actually need secondary winches; the weather primary is free of sheet.
Fair leads,
Brion Toss


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