Tighten Backstay?

[Spirit (of Glenans)]

The cap shrouds on my Dufour 30 Classic are attached to an internal structure within the mast, and emerge through oblong cutouts on either side. On my last trip to the masthead, in early March, I noticed that both shrouds were touching, and chafing, the rear edges of the cutouts where they emerge. My take on this situation is that there is not enough rake in the mast to pull the masthead aft enough to allow the shrouds to sit centrally in these cutouts and that the remedy is to increase tension on the backstay to reintroduce the rake.
Should I just tighten the backstay, assuming that the forestay has also lost tension, or should I compensate by slackening the latter? Or should I ask a rigger to rectify the matter?
I should point out that the standing rigging was replaced about four years ago, but has received no adjustment in the interim.

 

[fredrussell]

I’d speak to a rigger myself. Not an area to get anything but pro advice surely?

 

[lw395]

What style is the rig?
It could just be main shrouds are too slack, or lowers too tight.
No you should not just pull on the forestay, you should check everything.
Possibly the shrouds are attached wrongly inside the mast.

 

[Quandary]

Abbreviated instructions for setting up a deck stepped fractional rig (also available in more detail from Selden)
Step mast with everything 'just tight'
Adjust uppers to ensure mast is centred, use a halyard to measure.
Adjust rake (uppers, forestay if adjustable) using the main halyard with a bucket of water as a plumb bob. ( Anything more than about a foot at deck level is usually too much.)
Pull on backstay to introduce pre-bend the amount you want is dependent on the condition of the mainsail
Tighten lowers (evenly) until they are really hard removing some of the prebend. Release backstay.
Tighten uppers sighting up the mainsail groove to make sure everything stays straight.
Apply a bit of backstay (with swept spreaders this just needs to be hand tight until going to windward.)
Go sailing in 3-4 heading to windward, if leeward shrouds are slack tighten, tack tighten by same number of turns.
Uppers will still be just slack but not floppy.
Check shape of mast again adjust amount of prebend with lowers. At least a visual check that spreaders are even in both planes, I use a template and usually go through the whole procedure at least twice.

This is a shortened version but as you do it each year you will learn what gives you speed and pointing. A mast tensioner can be useful but a lateral tug at shoulder height tells you as much. The uppers will displace three times as much as the lowers which will take most of your strength to move.
If, when set up correctly the spreaders roots are chafing speak to an experienced rigger, you may have trouble finding an expert, many guys who have not raced and step masts know no more than you can read on Seldens website, sailmakers usually know a good deal more about it, that is why when you are ordering sails you get the sailmaker out on your boat and remember everything he tells you.

 

[neil_s]

When your rigger replaced the wires four years ago, he would most likely put some tension on them for safety, but would be expecting you to come along later and adjust it all to your own preference! The Selden site is most helpful - told me all I needed for my own boat!

 

[VicS]

This is the Selden advice referred to

http://www.seldenmast.com/files/595-540-E.pdf

 

[William_H]

I have not seen this kind of shroud attachment to the mast. It sounds a bit odd to me. However I wounder just how much change of direction of approach of the shrouds to the slot you would need to reduce the contact you are concerned about. I imagine you would need to move the mast top a long way aft to reduce contact. This might leave the mast too far aft for aesthetics or good sailing.
Secondly I wonder if a bit of wear of the SS on the ali mast will really matter.
I am aware of the shroud attachment where a SS plate is attached in side the slot and the shroud has a lug swaged on the end. Goes in and turns 90 degrees. In this case the slot and plate should be angled to accept the shroud coming from aft of abeam the mast but is often straight vertical so offset of shroud approach does not matter. I mention all this just on the off chance you have this system and di not recognise it. ol'will