E29 backstay

Hi all,

Looking for some wisdom/advice.

I currently have a split back stay with the associated tensioning device. Works fine as far as tensioning goes. I am not entirely happy with it though.

I think that when it was installed the brackets that the split attaches to were installed under zero tension. As a result, when tension is applied, an angle develops between the bolt line on the bracket and the rigging wire. More tension, bigger angle. I recognize that some variation in the angle is inevitable, but I seem to be on the wrong side of things. Would prefer if it had been installed so that things lined up when tension was high.

In addition, the split back stay simply gets in the way all the time. I am on the tall end of the spectrum so when standing it gets in the way. It also seems to magically get in the way when I am sitting.

So, thinking to go back to a single back stay. Options are a hydraulic tensioner (big $), a "screw/wheel" style tensioner (less $ but bulky), or a simple block/tackle system.

I am leaning towards the simple block/tackle system. My question is - how does one size the block tackle system? What is the backstay load on an E29?

Thanks in advance,

Peter

AFAIK, 10% of breaking strain... 750-800 lbs? Do you do a lot of backstay adjustment on your E29? I just have the stock turnbuckle.

To be sure I understand, are you suggesting that the system should be designed so that the actual load is 10% of the breaking load?

If I look up breaking strain of wire rigging I get


The owners manual specifies the rigging as 1x19 7/32 so that would correspond to about 630 lbs at 10%

However, i guess one should then take a similar approach to sizing the tensioner then? Go for 6300 lbs? Or thereabouts.

Do I have a lot of adjustment? Not 100% sure how to answer that without a comparison boat. I have never felt like I did not have enough.

Peter

Hey guys. Lets start off by first establishing that the 10% of break strength will not correspond in any way to the tension on the tackle. We are deflecting the wire at a steep angle and therefore you have gained tremendous mechanical advantage / leverage. Also you have split the load between two wires below the triangle plate. the bridal wires are sometimes downsized from the main backstay. I have sailed and owned boats with split back stay tensioners and I like em. Their simple, cheap and quick as lightning to adjust. I have a single back stay with hydraulic tensioner now and would say thats every bit or more in the way. split backstays are devised to add room to the helm.
The keys to good operation are as follows.
A high quality low friction tackle arrangement with smooth cam cleat w adjustable angle on your lower fiddle block. ideal set up would be 57mm carbo harken PN 2676. If you have a triple single block arrangement and not a dedicated backstay truck that will hinder things as well. ideal part would be Johnson 38-203. this truck is rated for max 3/16 wire but I guarantee it will be just fine w 7/32. Lastly I have seen split BS where the bridal is not long enough. perhaps you need to raise the whole operation up which would be relatively easy and inexpensive since shortening the backstay is no trouble and then two short bridal wires. I have sailed the E29 and its a great boat! I would think you should be comfortable back there provided the tackle is set up correctly. You could do this all at the dock with mechanical terminals. I also like the shaefer triangle plate.



When I set up a split BS tensioner heres the process.

1 determine that the rake of the spar is correct.
2 check to see if you bridal set up looks to be a reasonable height. I would guess at 8-8-6' from the coaming / tang measured vertically.
3 set your static backstay tension (which is essentially sloppy) 1' deflection by hand approx.
4 with the BS set at it loosest setting staticly
(as per johnson recommendations)
NOTE: For maximum car release, use a 1.5 to 1 ratio between backstay base width and car height. For example, if backstay width is 5 feet, car height should not exceed 7-1/2 ft. to 8 ft. in height off deck. Higher ratios may require manual release with aid of boat hook, etc.
4 4:1 tackle with cam cleat mounted off to preferable side. I mount a diamond pad eye as close to one side as feasible.
another little trick is to have a handy hanger on the rail to collect the excess line. If you find that you have gobs of line you could most likely get away with a 3:1 purchase as I would think this is more than sufficient for the tension you require and reduce line further.

Hope this helps.
Capt. Ian

Pondering method and result

Perhaps some "real world" numbers might help a little. We have a SailTec hydraulic integral backstay adjuster. I leave it tight but under a hundred # when parked. For going to weather and taking sag out of the headstay I pump up to about 1000# on the gauge.
I have pumped it up past 1500# a few times but pointing does not improve much, and as we get closer to 2K the boat starts to make some creaking sounds.

More seriously, you can also look at the various cascading purchase set-ups on the sites like Harken and see what ratio's they picture and I recall that they are arranged by size of boat and sail plan.

Whatever you decide on, make it easy to adjust with one hand, while your other hand is steering and you are looking ahead focusing on course.

Yea, you have to be a little careful with these hydraulic backstay adjusters. You can do serious damage to the boat with them. I remember back when they broke the back of an America's Cupper in San Diego.

The one advantage I can see with the split backstay over the cascading system is the backstay is always solidly attached to the boat. In most of the cascading systems, I see a mixture of wire and rope that ends in, usually, two cleats. If you trust that, go for it. They certainly adjust well. Most of the rigs that use the cascades are pretty high tech bendy systems that need precise control. The average Ericson mast is not in that category and only needs to be tightened to tension up the forestay for windward work. You certainly don't have to make the boat creak!

My E29 Back Stay Adjuster



This is a photo of two my friends out for a sail... But you can clearly see the Backstay Wheel.
It is fool proof... and with a Mast Head Rige it realy only does two things....
1: Put some Froward Rack in the Mast when going downwind...
2: Tighten up the forestay when going up wind.

The Wheel adjuster was on the on Boat when I bought it. But I would buy one it was was not there.

Rick+

thank you all

Thanks to all who replied. A nice set of information to mull over. I have had a look at the Harken site and most of the block/tackle systems they have are for "small boats" and that got me to wondering about loads.

The 57 mm carbo block referred to below has a maximum working load of 792 lb. I think this was suggested in the context of a split stay system where, as it was pointed out, the load is shared between the 2 bridal wires and the tensioner itself, albeit with some reduction due to the angles involved.

Seems too small to use as a replacement for the split stay arrangement.

Loren - having never been near a hydraulic backstay adjuster, I have to ask - are the numbers you are quoting in lbs or lbs/sq. in. ? If in lbs/sq. in., do you know what the relationship is between that and the actual tension? I think they would only be the same if the piston had an area of 1 sq. in.

Best regards,

Peter

The possibility of block failure is real. I looked at the failure of a 12 part system for mainsheet adjustment on a Soverel 33 with a custom rig and I could picture that bringing down a rig if used on a cascading backstay. The problem was a little corrosion causing a hairline crack which then failed. The Soverel is close to the E-29 in weight so the cascading system it has would be about right. I can get some pix of it and post them and I can take some shots of a C&C99 with the cascading system.

The Hydraulic Backstay Adjuster would be both expensive and overkill for the 29. I could picture easily breaking things on a 29 with one. I do like the wheels, though. Simple, positive, easy to install. Just think of a turnbuckle with giant handles on it.

I've not used a backstay wheel, but have sailed with a split backstay/blocks arrangement for the past 12 years in our 1984 E30+. It has been great with no issues. I use it whenever the wind increases in the Strait of Georgia / Salish Sea.
Frank

There's a Ronstan backstay wheel adjuster on sale now on E-Bay for $399.99.

I got the shots of the cascading backstay adjusters today. The Soverel 33 is 5,800lbs but carries 538 Sq ft of sail making it lighter than the E-29 but it carries the sail area of an E-32. The cascade arrangement would be appropriate for the 29. Way complicated and way adjustable. The C&C99 arrangement allows for tightening with a winch. It is 9265lb with 562 sq ft of sail area. The system would be impossible to set up on a 29.

I would stay with the split backstay as they work very well and you already have it. If you want to get rid of the split, you can't go much better than the wheel.

Bob,

Thanks so much for all the ideas. Wheel does seem the simplest if I decide to change.

Best,

Peter

If I were your rigger I would do what I could to steer you away from a wheel adjuster. Personally I think their a PIA. their expensive, terribly slow to adjust, require some lubrication, and can have real propensity to work harden tangs that were never designed for such an arrangement i.e. E29's. Also they are heavy and with the rig slack (typically broad reaching or running) they will sway around and therefore should be set on a double toggle jaw (though seldom are!). All negatives in my book. In regards to load on the 57mm blocks (or equiv.) I am certain that 700+ lbs will be more than sufficient. Also unlikely that someone would produce 700+ lbs load by hand. 700 / 4 = 175lbs. The resulting tension transmitted to the backstay from deflection the bridal wires is what I believe to be referred to as a catenary that is point loaded. If a block were to fail you would not loose the rig and could easily jury rig a temporary fix. We need an engineer to chime in here. Yes the rig could easily produce a greater load than 700 lbs but the tackle arrangement does receive that load! the truck does and only fractionaly by trying to be separated by the two cantnary's trying to be returned to a straight line. My trig skills are non existent but I know it is a complicated calculation. So as a shad tree engineer I shall use the following painful example. One helpful chap on your dock fending your boat off via a lifeline can fold up stanchions, bend pulpits, break fittings and welds with relative ease. a very strong man on his feet can't produce as much force as even his body weight, so that deflection produces huge increases in tension. This is why we jump and deflect halyards! I don't think were looking at the real physics here regarding the load on the blocks. Again this is all dependent on several factors. length of bridal wires. distance between mounting points at the transom, elasticity of the wire, friction, etc, etc. I just know from almost 40 years of sailing that this arrangement works and works well. Again just my typical overstated opinion. keep it simple, effective, and cheap. If we have and engineer in the house please chime in.

Hope this helps. Capt. Ian

Jenkins said:

Thanks to all who replied. A nice set of information to mull over. I have had a look at the Harken site and most of the block/tackle systems they have are for "small boats" and that got me to wondering about loads.

The 57 mm carbo block referred to below has a maximum working load of 792 lb. I think this was suggested in the context of a split stay system where, as it was pointed out, the load is shared between the 2 bridal wires and the tensioner itself, albeit with some reduction due to the angles involved.

Seems too small to use as a replacement for the split stay arrangement.

Loren - having never been near a hydraulic backstay adjuster, I have to ask - are the numbers you are quoting in lbs or lbs/sq. in. ? If in lbs/sq. in., do you know what the relationship is between that and the actual tension? I think they would only be the same if the piston had an area of 1 sq. in.

Best regards,

Peter

Click to expand...

By the later 80's, EY was installing integral hydraulic backstay adjusters on quite a few of their boats. Ours had one installed as a stock piece of gear. It was a Navtec product, and after I had it built once and it failed again, I changed to a SailTec.
They are a small company and very helpful when I have had a question.
https://www.sailtec.com/products/hydraulic-integral-adjusters.html

I would suggest asking your very logical question to them directly. Tell them I said hello, as well.

Loren

Loren,

Thank you very much for your response. I found this document from Navtec - http://www.sailtec.de/pic/upload/navtec_integral_serie-8le_manual.pdf - that tells you how to convert pressure readings to "pull force" as they call it for their units.

The conversion factor depends upon the size of the hydraulic unit - the unit they refer to as a size of -12 specifies that at 1000 lbs hydraulic pressure you get 1500 lbs "pull force" for example.

I note looking at the Sailtec site that the gauges on their units read in psi (and bar) so a conversion factor would be needed for one of those and it would depend upon size as well.

If you know which unit you have, I would be happy to email them.

Best,

Peter

Peter, our Olson 911 is just under 30 feet and we have a -10 Sailtec on our boat which would most likely be the size you would need as well. When we bought the boat it had a slight leak, and had it serviced by Sailtec for a fraction of what a new one cost.

That said, another 911 owner went to a purchase system which is detailed in this thread http://www.ericsonyachts.org/infoex...Backstay-Upgrade&highlight=olson+911+backstay

Hi Peter,
Very Interesting. You have found what appears to be German distributor ("Sailtec") selling Navtec parts. Perhaps they avoid legal problems with their name because they are not a manufacturer. i guess, perhaps.
They note that Navtec (a part of the Lewmar empire) no long sells parts. The totally different company that produced our adjuster is still in business , tho.

As for translating the gauge face, I have no idea if this applies to a rival company's product from the USA.

Interesting trivia in any case.

Hmm! Sailtec is selling Navtec parts? I will have to check. The pressure gauge on my 1030 looks worse than the lenses on my Lewmar hatches. I'll have to see if I can get a new one.

Note the brand name - it's important

supersailor said:

Hmm! Sailtec is selling Navtec parts? I will have to check. The pressure gauge on my 1030 looks worse than the lenses on my Lewmar hatches. I'll have to see if I can get a new one.

Click to expand...

Just be aware that the German company with the web site is probably not related to the American manufacturer, 'SailTec", and is selling NOS parts from the Lewmar subsidiary brand, Navtec. Might be good to have a part that fits your old adjuster... or the gauge might be generic. (?)

As advised, just call up SailTec and ask your questions... best starting point if nothing else.
https://www.sailtec.com/products/hydraulic-integral-adjusters.html


Loren