Batten for marking out mainsail roach

[Poignard]

I need a 32-foot batten to mark out the curved leech of a mainsail I am altering but it would have to be transported in four 8-foot lengths (approx.) to fit in my car, then re-connected on-site.

The idea is to borrow a church hall and lay the sail on the floor with weights holding the batten in place whilst I mark the sail with a pencil.

Some material for the batten that will take up a fair curve is needed.

It must also be cheap as I will probably discard it afterwards.

Any ideas for suitable batten material, please?

 

[wilkinsonsails]

Use a string line between the battens ,eye it up for fairing with weights .
You don’t want a curve between the battens. with soft fabric you usually need a slight concave .
You won’t really get a fair curve with joins ,if you do find a suitable stick .

 

[greeny]

Do you know any coarse fishermen? (haha) If the use a pole for fishing they are often between 11 an 14 metres long. See if you can borrow one of their old ones.

 

[Hoolie]

Thin plastic curtain rail, with joiners, if you're not convinced about string theory. Though you could use string to maintain the curve you want

 

[Poignard]

Use a string line between the battens ,eye it up for fairing with weights .
You don’t want a curve between the battens. with soft fabric you usually need a slight concave .
You won’t really get a fair curve with joins ,if you do find a suitable stick .

Sorry, I should have explained. There will be no battens.

I am doing a 'roachectomy' on an old sail so there will be a hollow leech.

 

[wilkinsonsails]

The same applies, though you need a collection of 1” steel rod off cuts . For a 10m leech round about 12 of them .
Check the fairing by eye from head or clew ,allowing for a headboard if using one ,you can easily move the weights
in or out to get the curve fair .
You can do the same thing with push pins but not on a rented floor ?.

Then mark under the string line using a short ruler .Once that’s done, you can use a longer batten say a metre ,to line them all up .

 

[Poignard]

The same applies, though you need a collection of 1” steel rod off cuts . For a 10m leech round about 12 of them .
Check the fairing by eye from head or clew ,allowing for a headboard if using one ,you can easily move the weights
in or out to get the curve fair .
You can do the same thing with push pins but not on a rented floor ?.

Then mark under the string line using a short ruler .Once that’s done, you can use a longer batten say a metre ,to line them all up .

Let me see if I have got this clear.

1. Make 12 small round steel weights, 1" diameter.

2. Lay out the sail on the floor.

3. Position the weights where the new leech is to be so as to produce a fair curve by eye.

4. Stretch string around the inboard side of the weights.

5. Mark the sail below the string so that there is a series of straight lines marked on the sail.

6. Remove weights and string.

7. Using the straight lines as a guide, mark a fair curve with a flexible batten.

Is that right?
.

 

[wilkinsonsails]

Yes that’s it exactly.
It was one of the original ways I was taught .
We lofted the larger barge Sails in our village hall using this method ..
You can’t transport a pair or 45ft stiff GRP long battens that easily , so the bit of string and the weights served us well..

 

[William_H]

Coming back to basics a roach is made to give the mainsail the biggest area for the available space. ie the triangle within the back stay. That is unless you intend to release the back stay with a spring to pull it away when tacking. Assuming that is not the case then you need to mark out the location of the back stay in relation to the mast. ie locate the mast crane end and the back stay chain plates then locate the sail ie mast and boom in relation to the back stay.
Many modern boats then will have a square top to the sail to fit inside the mast crane then something more like a straight line or perhaps some roach down to the clew.
OP seems to be seeking a beautiful symetrical rounded roach which might only be found on a main sail where there is no back stay. In other words the beauty of the symmetry of the roach is a lesser concern. Then as said the leach is usually straight or concave between the batten ends . ol'will

 

[PuffTheMagicDragon]

Plastic conduit. Cheap, flexible and comes in 3-metre lengths, easily joined together.

 

[Poignard]

Coming back to basics a roach is made to give the mainsail the biggest area for the available space. ie the triangle within the back stay. That is unless you intend to release the back stay with a spring to pull it away when tacking. Assuming that is not the case then you need to mark out the location of the back stay in relation to the mast. ie locate the mast crane end and the back stay chain plates then locate the sail ie mast and boom in relation to the back stay.
Many modern boats then will have a square top to the sail to fit inside the mast crane then something more like a straight line or perhaps some roach down to the clew.
OP seems to be seeking a beautiful symetrical rounded roach which might only be found on a main sail where there is no back stay. In other words the beauty of the symmetry of the roach is a lesser concern. Then as said the leach is usually straight or concave between the batten ends . ol'will

I want to alter the sail so it has no battens. Doing so means it cannot have any roach, since there will be no battens to support it.

But if I just make the leech dead straight, it will flutter. So it is necessary to have a concave leech, and that is what I need to mark out on the sail.

 

[Plum]

I need a 32-foot batten to mark out the curved leech of a mainsail I am altering but it would have to be transported in four 8-foot lengths (approx.) to fit in my car, then re-connected on-site.

The idea is to borrow a church hall and lay the sail on the floor with weights holding the batten in place whilst I mark the sail with a pencil.

Some material for the batten that will take up a fair curve is needed.

It must also be cheap as I will probably discard it afterwards.

Any ideas for suitable batten material, please?

The advice from Wilkinson Sails looks excellent but may I suggest one of these to lay around the weights. I have a shorter one used for fairing. Silverline 656602 Drain Cleaner 10 m: Amazon.co.uk: DIY & Tools

www.solocoastalsailing.co.uk

 

[Hydrozoan]

The advice from Wilkinson Sails looks excellent but may I suggest one of these to lay around the weights. I have a shorter one used for fairing. Silverline 656602 Drain Cleaner 10 m: Amazon.co.uk: DIY & Tools

www.solocoastalsailing.co.uk

Or at about half the price, 10m of curtain wire? 50cm 1m 2m 3m 4m 5m 10m 20m 30m WHITE NET CURTAIN WIRE FREE HOOKS AND EYES | eBay (Might depend I suppose on the relative usefulness after completion of a drain cleaner versus curtain wire!)

 

[Poignard]

Plastic conduit. Cheap, flexible and comes in 3-metre lengths, easily joined together.

That was a good tip!
I bought 4 lengths plus couplers from B&Q , then returned them for a full refund afterwards.

 

[lw395]

I want to alter the sail so it has no battens. Doing so means it cannot have any roach, since there will be no battens to support it.

But if I just make the leech dead straight, it will flutter. So it is necessary to have a concave leech, and that is what I need to mark out on the sail.

I think if you do this, you will get a poor result due to the weft no longer being parallel to the leach? Unless the roach was minimal to start with?

IF you see, for example a laser sail set on the rig with the battens removed, it doesn't just fold over around a straight line from head to clew, it distorts like a bag of spanners. For some reason, people trying to sell cheap lasers on ebay are very keen to demonstrate this
laser one sailing dinghy old and not a race winner hence the price with 2 mains | eBay
Lasers don't have much roach.