mainsail catching backstay

[Kleverken]

Hi all
Have a SO35 and have noticed in Very light breeze that the top batten catches the backstay, holding till the wind picks up,when it then flicks accross.
under normal conditions the sail crosses and you dont notice in midst of everything else. As I see it this will end up wearing at that point.Maybe doing something stupid but cant just see how to stop this. any suggestions ?

 

[ShipsWoofy]

Presumably you or the previous owner upgraded to a fully battened main without checking the clearance.

I would suggest your only options would be to down grade to a 3/4 batten sail or replace the single backstay with a twin stays, but that would bring a whole host of problems with tensioning etc,

My guess will be live with it, if it breaks get a new sail built that fits the boat. /forums/images/graemlins/smile.gif

 

[Kleverken]

Boat was delivered new two months ago . so I guess the problem will be somebody elses to sort. but cant see as its a production boat how the riggers have got it wrong .. if indeed they have

 

[Phoenix of Hamble]

Is the batten in a pocket in the sail?... or does it have an end fitting with a screw or rope tensioner?.....

If it does then these can protrude quite a long way... this could be your cause?

Either way... in the mean time, at least as a temporary until you get a permanent resolution, fit a sacrifical strip of some kind....

 

[Ships_Cat]

I am not sure what the SO35's sailplan is supposed to be like in way of the roach, but it is not unusual for the sailplan to be designed with the roach fouling the backstay in order to get more elliptical shape into the sail.

You could ask Jenneau as to what it is supposed to be like but I don't think that I would be too bothered myself. If you want some comfort have a look at the sailplan of the HR37 on the Hallberg-Rassy site.

Some big cruising boats have been designed with very large overlaps, for example some of the Dashew Offshore Design ones - have a look at the third photo down on http://www.setsail.com/dashew/dashoff.html. If you look carefully you can actually see the backstay and its relationship to the leech.

John

 

[William_H]

Does it occur at different backstay tensions. Of course this doesn't help as you must have the correct backstay tension fior the conditions.Presumably it is catching at a batten end. If you shorten the batten it may be possible to tuck it in further into the sail while maintaining the correct batten tension. that depends a bit on the batten arrangement.
Next option is to not pull the main so high up the mast although that seems a bit drastic assuming the tack (bottom front) of the sail is attached close to the boom.
the next fix is to fit or extend if fitted a backstay crane. This is a solid horozontal extension at the back of the top of the mast where the backstay attaches. In my case the crane is U shaped and two pieces of S/S could be fitted in to the U with a hole to take a bolt in the existing clevis pin hole for the backstay and another hole in the plates to take the backstay clevis pin. A section of the plates forward would keep the plates horozontal. You probably only need to extend by 50mm. If you dont have a crane then it is a riggers wekding job to fit one. I sympathise that it is anoying and if it is new the manufacturer should fixed. regards will

 

[FullCircle]

Dear Kenw
Welcome as a new user, but you are obviously going to be my bad news bringer. I am eagerly awaiting delivery of my SO35 (Lift Keel), and with respect to the other posting assistants here, this is my twopenny worth.
First I tried without success to delete the sails from the package. /forums/images/graemlins/laugh.gif
But, as you will be aware, and the others may not be, is that there is no variable backstay tensioner on the SO35, and there is a small horizontal overhang already.
This then probably means that either the mast is canted back or forward too much, pullling the sail into contact with the stay, or that the sailmaker has given you some extra unwanted material for free. Either way, contact your dealer straight away, and have him investigate. The chafe will become an issue over time, as I am expecting the main to last a good few years. On a racing boat, a full cut roach is prob a good thing as they throw their mains into the garage after half a season, never to be seen again until the boat is sold.
If you cant be arsed with that, how about cutting 1/4 an inch at a time off the batten and see if it clears.
Did they send yours with the right specification overall?

/forums/images/graemlins/wink.gif


Cheers
Jim

 

[Kleverken]

Jim

(that there is no variable backstay tensioner on the SO35,)

that s what got me thinking. Had thought about the mast having been tensioned up wrong but am not very well up on "bending" masts,more used to big lumps of wood keel mounted. Going to boat this weekend so will try to have a word with the guys who do the rigging as they had also got the single line reefing wrong (twice). AFter all that still love it. /forums/images/graemlins/grin.gif(mine also lifting keel.)

 

[ecb]

My friend with a SunFast 26 had exactly the same problem. It was really infuriating in light airs.... exactly when you want a nice clean tack!

The North Sails website has some FAQs on overlapping roach mains...

SNIP > The majority of North's cruising customers prefer to have the sail clear the backstay without hitting it. Even if you don't want the sail to interfer with the backstay, we can proably build a sail with significantly more roach area than your existing mainsail. If you don't mind the sail striking the backstay during tacks and gybes we can build a mainsail with a more aggressive shape in the upper sections of the leech. We build plenty of cruising sails that hit the backstay. Our batten pocket construction methods and chafing systems are well established and you can count on using the sail for 2 or 3 years or 10,000 to 15,000 miles of sailing before you will need to renew the chafe protection. The objections to a sail that overlaps the backstay are that it can hang up in very light air conditions during tacks and gybes, and that the battens bang against the stay during raising and lowering the sail or motorsailing if the boat is facing directly into the wind. For some sailors, these are minor annoyances when compared to the performance benefits of the increased sail area and more efficient sail shape. <SNIP

I think that decent sailmakers get round the problem by covering the back portion of the top batten pocket with some low-friction material. Also I guess a slighty less firm top batten would have helped.

However, in the end my friend with the SunFast26 had the sail re-cut and the amount of roach reduced significantly!!!!!

 

[FWB]

Yet another reason to sail a gaffer!

 

[Will_M]

Its the same deal on our J109, and yes its ment to be like that.

Like you say its only light wind where it catches, if the wind is that light then often it can be 'flicked' out as it where.

But the real easy solution is as you go through the tack bang on aload of kicker and then release after tack, job done that way! Although we do change to the top battern to a lighter weight battern in the lower wind strengths, all fairly stright forward.

 

[boatmike]

Could you possibly lower the gooseneck and move the whole sail down the mast a bit?

 

[charles_reed]

I really wouldn\'t worry

If, little Neddy, you're sitting comfortably, I will tell you a story:-

Sailing in the Med, where there's either too little or too much wind, I decided to get a fully battened mainsail, with a really aggressive roach exploiting every mm of boom and main. This gave me a 32.4M2 main instead of a 28M2 sail (for the senior readers that's 343ft2 instead of 296ft2).
This resulted in a very welcome improvement in light-air performance but, due to an geometric error on my part, in calculating the backstay offstand on my new mast, when I got the sail the top 3 (of 5 battens) overlapped the backstay, in the case of #4 (from the bottom) by 316mm (12.5" for imperialists) and about half this for the 2 on either side.
My lamentations were grievious and the sense of woe was enhanced by a number of experts (riggers and sailmakers) who proposed a number of extreme solutions ranging, from cutting the foot off the sail, through slicing off the roach, to replacing the standing with twin running backstays.
The only person to give me comfort was an Aussie called Hob, working for Harken in the US, who reckoned anything up to 2' was OK. As he used to helm Sidney Harbour Skiffs many might consider him an eccentric advisor.
In the end I put in a 4th, single-line, lower reef and gave it a try.

Two years later and, at the risk of being complacent, I'm still sailing and instead of having irrecovable lee-helm at anything under 4 knots apparent the boat handles superbly and no battens have been broken and there are only very occasional (and only in light airs) refusals to go through the wind.

You see when the battens bend, they pull the roach away from the backstay. If there is insufficient wind to make the sail take up its camber that's when the main balks.
To guard against that I slacken off the backstay and reduce vang and mainsheet tension before tacking. Admittedly my backsaty is only there for mast bend, having 22.5degrees sweepback on the spreaders has some advantages (but many drawbacks). So here are my suggestions:-

1. Try tacking with less mainsheet and vang tension and slacken off the backstay. If that doesn't work.
2. Use your flattening reef reef in those conditions where you're getting the hangs.

Rest assured - there's little wear occuring, if you're concerned about that put some HDPE around the point of contact.

Any queries PM me.

 

[anglo_saxon]

Re: I really wouldn\'t worry

could it possibly be that the forestay is to tight reducing the mast bend. may be completly wrong on this.

 

[charles_reed]

Re: I really wouldn\'t worry

If you're assuming a masthead rig that could be the (unlikely) case. More likely the other way around, backstay too tight.

Wouldn't like to comment further without looking at how the rigging is set up.

 

[Oldhand]

In light breezes you shouldn't have a lot of backstay tension on so as you tack just give the backstay a good shake and the sail will pass. Did that for over 10 years on our last boat, no problem at all. /forums/images/graemlins/smile.gif

 

[Kleverken]

Re: To all

thanks for all the input will try to sort it out with riggers and/or agents this weekend and if there is a definitive answer i will drop a post on this thread /forums/images/graemlins/confused.gif

ken