Hello,
Do any of you have running backstays rigged? If so, how have you connected them to the hull? Thank you in advance for help.
Cheers,
Does anyone know where Renegade is these days? Or detailed photos/drawings of her rig?
I ask because my understanding, limited of course, is that:
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Hale Field designed the rig of Renegade and included running backstays;
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Larry Pardey saw Renegade (by then no longer owned by Hale Field) and considered her the closest boat to his ideal, and then followed up by talking to Hale Field who introduced him to Lyle C. Hess;
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as part of what became Larry’s ‘Go Simple’ philosophy, Larry spurned running backstays so …
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when Larry talked with Lyle C. Hess about boats, leading of course to the design of Seraffyn and eventually to the design of the Bristol Channel Cutter, a fixed backstay was a fundamental part of the rig and the boat design.
In my state of ignorant bliss, I’ve always thought very kindly of Larry, because:
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I prefer not to fuss with running backstays; and
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when I sail on other boats that do have running backstays, I’ve found that only the most competition-oriented racer types bother with cranking and de-cranking running backstays.
Bil
Hello Bil,
I had thought I had dispensed with the idea of runners as well but a recent demonstration of my mast “pumping” has me reconsidering them. I may have been a bit obtuse in my request for info but the runners would oppose the forestay and not the headstay.
Cheers,
Tom
Tom: Hi!
I had thought I had dispensed with the idea of
runners as well but a recent demonstration of my
mast “pumping” has me reconsidering them.
Was that mast pumping when at anchor, or mast pumping when under sail?
Zygote’s mast pumps under certain wind conditions when at anchor or docked. I don’t think I’ve noted pumping when sailing.
In Words, the word list I wrote for Zygote (in yet another failed attempt to persuade my daughter to get into sailing and inherit Zygote), I did my best to describe mast pumping:
“mast vibration due to shedding of a Kármán vortex street (named after Theodore von Kármán) along the bare mast; noticeable when the frequency of vortex shedding coincides with the natural resonant frequency of the mast section. [yachting English 1976 mast pumping; MAST; + Modern English 1803 pump, to work with an action like that of a pump handle, to shake vigorously] Mast pumping occurs at anchor or when berthed with strong winds. The mainsail, when hoist, prevents a vortex street forming. Mast pumping can be defeated by wrapping a hawser in a spiral around the mast to form a helical fence, or by hoisting a small fender (longer than the diameter of the mast) using the main halyard and a tag line, to about 2/3 mast height.”
Others argue that changing (meaning increasing or decreasing) the tension of the inner stay and lower shrouds to some magical point does the trick. I’ve never discovered the magical tension combination that works.
Another way of defeating mast pumping when not under sail is to somehow fly an abbreviated sail: a piece of sailcloth longer than the diameter of the mast and about as long as the diameter of the mast, at that magic 2/3 mast height position. Working out how to do that with sail slugs in the mainsail track defeated me, so I have tried the thick hawser around the mast and the small fender tricks.
Bil
Ahoy Tom and Bil , I am wondering about , " a recent demonstration of my mast “pumping” , Tom , what was that demonstration ?
And Bil , " I have tried the thick hawser around the mast and the small fender tricks." , so did this work ?
Shipwright’s Regatta tomorrow Feb 28th , there will be Hess boats attending .
Douglas: Hi!
And Bil , " I have tried the thick hawser around
the mast and the small fender tricks." , so did
this work ?
I’ve never done the right thing of making a note in the log when I’ve had mast pumping.
My feeling is that Zygote’s mast pumps when at anchor (i.e. head to wind) with winds of 35 knots or more.
Mast pumping is very much less common when Z is in her marina berth. I usually dock Z with her bow pointing into the prevailing SE wind, but the wind is not always precisely at SE and I figure wind in the marina is much disturbed by the forest of other masts upwind.
I’ve a length of 3 strand nylon, about 1" in diameter. I’ve done a loose spiral of it around the mast, starting from the lower spreaders down, at one anchorage when the wind forecast was 35+ knots. I didn’t notice mast pumping, but I cannot swear it was because of the hawser or it was just that the wind didn’t get to the right speed.
I’ve a small fender ready for next time (spiralling the hawser around mast takes effort up the mast steps and time). My idea is to make the main halyard to a loop of small stuff through the top eye of the fender and another, longer length of small stuff to act as a downhaul to the bottom eye of the fender. And I had in mind that I could use that downhaul to haul the fender aft away from the mast if it starts bouncing on the mast.
Shipwright’s Regatta tomorrow Feb 28th , there
will be Hess boats attending .
Wonderful! Hope you enjoy it! Lyle’s birthday is 19 March, so this is a particularly good time for owners of his designs to get together.
Is Calliste in the water? Will she be at the Regatta?
Bil
Hello all,
It would appear I’ve used the wrong term! The mast pumping I referred to was the flexion seen as an assistant pulled on the forestay (boat at dock). I could see the dramatic motion of the mast particularly from the upper spreaders to the top. With this type of movement noted I could only wonder at what my sail shape would be as I moved through peaks and troughs as well as gusts while going to windward (try as I might to avoid windward!) As an aside, my rig is well tuned.
Cheers,
Tom: Hi!
I was in my backyard pruning our mango tree and your post came to mind, specifically:
The
mast pumping I referred to was the flexion seen as
an assistant pulled on the forestay (boat at
dock). I could see the dramatic motion of the
mast particularly from the upper spreaders to the
top.
That doesn’t sound right. Added tension on the forestay should be resisted by the pretension in the backstay, right? That’s the theory of a masthead rig (which is different from the theory of a fractional rig).
As an aside, my rig is well tuned.
And that made my brow furrow. Even while contemplating whether slicing off another bough might persuade our mango tree to reconsider its attitude to fruiting in a season or three (not many fruit last season and all enjoyed by the fruit bats, not me, because the fruit were way out of my reach).
Not being a professional rigger, let me lay out my understanding of how Zygote is rigged (because Terrier may be quite different).
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Zygote has a roller-reef foil on her jib stay, so fore-and-aft tension is handled by tension in the backstay only.
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Zygote has 9/32" 1x19 ss wire for the jib stay and the backstay. 9/32" is 0.28" or 7.14 mm. Notional breaking load for 0.28" ss wire is 8,700 imperial pounds.
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Roger Olson, who taught me how to tune Zygote’s rig, said to make the backstay “bar tight”. I’ve a rig tuning book on board (where I’m not at the moment) by a guy whose name I cannot pronounce or spell that gives a numeric guide for ‘bar tight’. Without that book, I today turned to the online Selden tuning guide at http://www.riggingandsails.com/pdf/selden-tuning.pdf which gives a slight different but similar numeric guide for pretension in backstay of a masthead rig:
“Tension the backstay to 15% of the breaking load of the
wire. Over a short period (a few hours) the load may be
increased, but not to more than 30% of the breaking
load of the wire.”
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I cooperated with the late Tom Harrer (of BCC White Wings III, peace be upon him) to come up with an easy guide to backstay tension for our boats. Tom and I came up with the target backstay pretension of 1,740 pounds, or about 20% of the notional breaking load. That’s 47 or 48 on one of the inexpensive Loos gauges. Tom and I sailed our respective boats, trying to work out tension that gave best windward performance. Tom preferred a Loos gauge figure of 47. I plumped for 48. The scale of the el cheapo Loos gauge is such that the difference between 47 and 48 is not significant.
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I’ve not tried tugging on the forestay, because on Z the jibstay is surrounded by a foil. I’m sure the masthead moves a tad under sail, but I’d be surprised to see dramatic movement with the backstay bar tight.
Hope that helps
Bil
Hello Bil,
Thank you for the thought put into my query! My mast is straight fore and aft with a bit of rake and tensioned appropriate as measured with a Loos guage at the dock and tweaked underway. I have also roller furling on the headstay (jibstay) but hank ons for the forestay. The motion noted is the fore and aft bowing centered where the forestay attaches which I thought might be reduced with the addition of opposing runners. I am often using my foresail in addition to varying amounts of the genoa when windward bound. So is it worth the effort to have better opposition to the forestay?
Cheers,
Tom
Hello Bil,
Thank you for the thought put into my query! My mast is straight fore and aft with a bit of rake and tensioned appropriate as measured with a Loos guage at the dock and tweaked underway. I have also roller furling on the headstay (jibstay) but hank ons for the forestay. The motion noted is the fore and aft bowing centered where the forestay attaches which I thought might be reduced with the addition of opposing runners. I am often using my foresail in addition to varying amounts of the genoa when windward bound. So is it worth the effort to have better opposition to the forestay?
Cheers,
Tom
Tom: Hi!
guage at the dock and tweaked underway. I have
also roller furling on the headstay (jibstay) but
hank ons for the forestay. The motion noted is
the fore and aft bowing centered where the
forestay attaches which I thought might be reduced
with the addition of opposing runners. I am often
using my foresail in addition to varying amounts
of the genoa when windward bound. So is it worth
the effort to have better opposition to the
forestay?
Interesting. I must admit I’ve not spent time looking watching the middle of the mast. I’ll have to put that on my list.
Zygote also hanks the staysail onto the forestay (which Selden prefers to call the cutter stay - the diagram in the Selden pdf is a lot of fun for a way of distinguishing among ‘cutter stay’, ‘inner forestay’, and ‘baby stay’).
Z has a Highfield lever on her forestay. We sometimes fly an overlapping genoa and prefer to unhitch the forestay and lash it to a stanchion, allowing easy tacking of the genoa. Other times I tack the overlapping genoa by roller-furling it partly, tacking, and then unrolling. In truth, we under-use the genoa.
Fore-aft stability in the middle of the mast is theoretically the province of the forestay and the lower intermediate shrouds.
Tom Harrer and I decided on a Loos gauge tension figure for the lower aft shrouds of 37 (equivalent to about 690 pounds) and 42 for the forestay (aka cutter stay or staysail stay).
I’ll have to wait until I’ve done some sailing while watching the mid-section of the mast to comment further. With luck someone else who has paid more attention will chime in …
My bow saw and I dropped one bough off the mango tree yesterday. Today I cleaned up and put the trash on the sidewalk for pickup by the local government’s contractor. I’ve decided a more vigorous trim of the mango is needed! So more pruning action to come.
Bil