Backstay Adjuster

[bayhoss]

I'm thinking of adding a backstay adjuster to my '86 E28 and a couple of questions come to mind. 1) Is the Keynon mast flexable enough to really benifit.
2) When reefing do you release the backstay to the orginal tension. As the main is made shorter it would seem to benfit less from the flex of the mast.

Thanks in advance for any help, Also, if anyone has a brand/type that they use I would very much like to hear of it.

Best Always,
Frank

 

[adavid]

I added a backstay adjuster to my '86 E-28, and definitely recommend it. It's a simple improvement, and makes a big difference. Though the mast is not as bendy as a typical raceboat, it definitely bends when you crank on the backstay. It flattens out the main, and opens up the leach, while also tightening the headstay. I just came back from sailing today in 8 - 14 knots. In 8 knots I would have no backstay on, and in 14 it would be cranked 1/2-way down. Without the adjuster and no weight on the rail (135% jib and full main), I would need to think about reefing. With the backstay adjuster, it is an easy way to depower.

In terms of the impact once you reef the main, it doesn't have as much impact on the shape of the main, but it does still tighten up the headstay, which is helpful.

You can see the setup that I have in the picture here.

Andy

 

[markvone]

Frank,

I agree with David. I added a simple 4x block and tackle to the backstay of my '84 E26 (also a 7/8 fractional) and the flatening effect was very noticable, even double reefed. The simultaneous tightening of the forestay and flattening of the jib combined with the flatter main covers a pretty wide wind range. My block/tackle had a releasable shackle on the transom in the center, attached to a padeye, so I could move it away to use the swim ladder and still pull straight down to squeeze the split backstay together. The ability of the Ericson's with fractional rigs (26-30 and 33RH) to flatten the bigger main without furling or changing headsails is one of their better sailing attributes, IMHO.

Mark

 

[markvone]

Sorry, that was Andy I was agreeing with!

 

[mherrcat]

I seem to recall reading somewhere that increasing the tension on the backstay of a fractional rig does not increase the tension on the forestay. Am I wrong?

 

[Frank Langer]

Hi Mark,

The one-pager on rig tuning in the Ericson 30+ manual (it's under the specs section in this site) does say that tensioning the backstay does not increase headstay tension.

I think the reason for this may be that the backstay goes right to the masthead, whereas the headstay only goes about 7/8 up the mast, so the backstay does not directly counter the headstay to tension it. Others may have other or better explanations.

Frank

 

[markvone]

Yes and No

The backstay will primarily bend the mast and flatten the main on a fractional rig. I think the tuning guides say what they say to keep people from tensioning their fractional rig backstays like they would on the more common masthead rig - to add headstay tension.

That said, something has to oppose the tension in the headstay. Swept back sidestays can do all or part of the job. But if you have a backstay and you tighten it, it will pull down and aft on the top of the mast which will primarily bow the mast center forward but also and pull aft to a degree on the forestay via a lever arm (the upper mast section). So as you flatten the main you also eliminate some sag in the headstay to a lesser but noticeable and useful degree.

 

[Seth]

Correct

Mark is right, and this is a matter of degree having to do with how bendy the mast section is. On the E boats the masts are not super bendy, so the backstay will have some effect on HS sag, wheras with a more racy bendy rig it is little or no effect.

Either way, the BS on the frac boats will never provide enough HS tension for optimal performance upwind in breeze-about the best you can do is stop the HS from bouncing around in waves when upwind in ligfht-moderate breeze. After than you either need running backs or swept back spreaders
Cheers

 

[bayhoss]

Thanks!

So, if I have this correct, the backstay on the fractional rig (even with the stiffness of the Kenyon mast) will do a very good job of depowering the main by controlling draft. But, don't expect a great deal of improvement on the HS.

Best,
Frank

 

[Seth]

Pretty much

If the rig is really stiff I would prefer to phrase it like this:

It will do a DECENT job of flattening the main, and only have a limited impact on the HS. It is affect the HS in the transition from light to moderate air, but have less and less as the breeze builds.

On the 28 types, you can really make a difference in sail shape by using the forward and aft lowers to set or remove prebend. If you have a deep mainsail, set up the mast with tighter fwd lowers and looser aft lowers. This will create bend and help flatten the sail. Or, you can also tune for conditions: on light days go for a straighter mast (less relative load on the fwd lowers) for a fuller mainsail, and on breezy days go for more prebend-and a flatter mainsail..

On some of the boats with a really stiff mast, runners will not help much (like the 28's), and the BS adjuster is really the best tool you have (plus rig tune of course). The bendier the rig the more this is true.

Hope this helps,

S

 

[Frank Langer]

Seth, how does this apply to the E30+?

Frank

 

[Seth]

30+

Hi Frank,
The 30+ is a little more bendy, so the backstay will be a little more effective for mast bend than the 28's, and a little less effective for HS control, since it is a bit more "fractional" meaning the HS does not extend quite as high proportionally up the mast. You can control prebend equally well by using the forward and aft lowers.
Make sense?
Regards,

S

 

[Frank Langer]

Hi Seth,

Thanks for your reply. Yes, I understand the backstay not going as high on the E30+, and I do find the backstay adjuster to make a difference when the wind pipes up. But my 1984 E30+ has the cap shrouds, intermediate and lower shroud, rather than the lower forward and aft shrouds. The one page rig tuning section from the E30+ manual advises no mast rake on the E30+, and doesn't address mast bend, which I found a bit unusual. At this point I have no mast bend, and the shrouds all tuned tight enough that there is no slack when the boat is heeled about 20 degrees in about 18 knot winds, with the cap shroud the tightest (I think at about 12% breaking strength), the lowers about the same and the intermediate a little bit less. The mast appears straight, both by sight up the mast track and by halyard measurement at the dock, and does not bend to leeward when I sight up the mast under sail. The furling headsail/headstay has about 6 - 8 inches sag in it. I would prefer to tighten this a bit more, but I have adjusted it as tight as it will go on the Harken furler and don't want to re-cut at this time. I have slight weather helm in higher breezes, but never alot of pressure on the wheel--at most the steering wheel is turned one quarter of one turn to counteract weatherhelm, and it can turn two full turns side to side in its full range from rudder stop to other rudder stop. When I turn the rudder that quarter turn at the dock, I can see that the rudder is turned just slightly from centre--maybe about 5 degrees, though it's hard to eyeball.

I can easily get the boat to 6 knots in about 15 - 20 knots wind, and on a relatively flat/low waves day, I have achieved 7.8 knots. I reef the main at about 18 knots and a 2nd reef at about 23 knots, to keep her on her feet and not heeled too far. Any other suggestions to help her sail to her potential? I am familiar with outhaul, boom vang, traveller, cunningham adjustments.

Thanks for any extra tips. In general, I am very pleased with how our boat sails, but always looking for ways to get that extra 1/10th of a knot!

Frank

 

[Seth]

Sorry I'm late....

Right, I remember now the rig is all in line, and deck stepped, right? This means you can't do a whole lot with tuning in terms of bend/prebend...

6-8" will be ideal in lighter air, and as long as you don't end up with much more than this in breezy conditions you are in good shape for a cruising genoa without a backstay adjuster. Your rig sounds failry well tuned-although a bit tight for light air sailing...


Sounds like you are getting very good performance from the boat. The big thing is whether or not you can get the mainsail flat enough when it is windy.
If you could post a picture of the mainsail trimmed going upwind sighting from the mid point of the boom I could have a sense of how deep it is to begin with, but the depth of the sail (if excessive) is the biggest problem in terms of creating too much weather helm and/or being overpowered. I tended to design cruising mains pretty flat to begin with so the boats would not be way overpowered as the wind comes up given most cruisers have very limited tools to change the sail depth.

I can give much better specific advice for you if I see how deep the main is to begin with.

Sorry for the late reply..

Cheers,

 

[Frank Langer]

Seth, and others, I've attached pictures of the mainsail....

Hi Seth,

Thanks for your reply above. I will try to attach pics of the mainsail ( I haven't done this before, so hopefully it will work). These pics were taken while underway in about 12 knots of wind, with outhaul almost fully applied, boom vang somewhat applied and halyard only tight enough to remove wrinkles. Boat speed on our E30+ was about 6 knots at the time. Sail trim isn't perfect, but hopefully will show mainsail shape. This sail is about 8 years old, but still serviceable in my opinion. I would appreciate any suggestions on sail trim or sail re-cutting.
Thanks,
Frank

 

[CaptDan]

Headstay-Forestay

For what it's worth.............

The late great Gary Mull used to throw fits over this terminology. He absolutely insisted that - if the 'forward vertical wire' is attached to any place beneath the masthead - it's called a FORESTAY. If it goes all the way to the top - it's a HEADSTAY.

I'll take my beating now.:nerd:

Capt Dan G>E35II "Kunu"

 

[Emerald]

For what it's worth.............

The late great Gary Mull used to throw fits over this terminology. He absolutely insisted that - if the 'forward vertical wire' is attached to any place beneath the masthead - it's called a FORESTAY. If it goes all the way to the top - it's a HEADSTAY.

I'll take my beating now.:nerd:

Capt Dan G>E35II "Kunu"

No beating on that one - you just made my life so much easier because now I can sort out (on my cutter rig) how to keep novice crew clear on which stay I'm talking about - yankee is on the headstay and staysail is on the forestay. Why didn't I think of that?

 

[CaptDan]

Why didn't I think of that?

I believe you just did, Sir.

Capt Dan G>E35II "Kunu"

 

[Seth]

Mainsail

Thanks Frank.

And thanks Dan-I think the great Gary Mull (also a hero of mine-remember "Improbable"? Awesome boat) is generally right, but this is in the sense of a masthead boat which may carry an inner forestay, at least I think so. I think when it is a fractional rig it is still applicable to call it a headstay. But, I wouldn't go so far as to argue the point with TGGM! Not that we could anyway, since he has passed....

Frank, your mainsail looks VERY deep for the conditions, and quite twisted at the top. As to the halyard tension, the draft distribution is quite uneven top to bottom-the top draft stripe looks OK at 45%-50% of cord length, but the bottom is super draft forward, and this may be the cause of the reverse you see in the lower section of the sail towards the leech, which can be fixed by a sailmaker.

You clearly need some mast bend to get rid of the draft for this condition, and if you can't add that adjuster, I would take this sail to have it flattened (remove some luff curve and than maybe add some take up in the leech to have the reverse curve corrected. I think a good sailmaker can see this and figure out how to accomplish all of this, but he will have to re-do the luff curve (remove the luff hardware and re-attach), and open up some of the shaping seams.

Ideally, you should have more mast bend to reduce the overall draft, and then lower the traveller and add some sheet to get rid of most of the twist. If you do that with the sail as deep as it is now you may find yourself overpowered, so job one is to get the sail flatter in these conditions and go from there..

This could be a $500 job, so it is something to think about, but if the cloth is healthy you will be much happier with the sail.

Let me know if this makes sense and/or if you have any other questions.
Cheers,
S

 

[Frank Langer]

Thanks, Seth. You have given me lots to think about and discuss with a local sailmaker. We are on a tight budget, so may have to think about how to achieve the best results for a reasonable price.

Thanks again!

Frank