Genoa fell down!!

[BobE]

My Genoa roller reefing failed on Monday en route to Cherbourg. The sail simply fell down when the top swivel came apart due to, (I think) the upper circlip thingy failing .
So now it’s being rebuilt.
But any comments on setup and/or tensions will be appreciated.
It seems to me that one should first set the length of the wire forestay to get a suitable mast rake. At a reasonable backstay tension (?? Wot’s reasonable??) (BTW forstay, backstay and shrouds are 7mm wire the babystay is 5 mm)
Then mount the foils ensuring that the top one can still rotate on the swage at the mast head when the lowest is clamped into the drum..
At this point I get even more befuddled than normal…
Why did the circlip fail? Had I overloaded it ? When sailing without all this gubbins we used to really pull up on the genoa halyard ‘till it was bar tight..
Now with the foil system I guess the luff sag is taken out by the foil and forestay tension and the halyard just tightens the luff tape to flatten the front of the sail and give a smaller angle of attack and therefore better pointing….
Am I right… Have I been over tensioning the halyard? Should I really whack up the backstay before adjusting the flow with the halyard…..
Help!!!!
Cheers Bob E….
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[Gin]

Don't know about the swivel circlip, but your idea for rakingmast and tensioning forestay/backstay is the right idea.

Get yourself a Loos tension gauge, Professional model as the smaller one won't cope with your 7mm wires (expensive at about £55). Then with your rake set as you want it tension up the backstay to about 20% of its breaking strain , this is for a masthead rig and assumes that forestay and backstay are the same diameter . Your cap shrouds want to be about 15-20% load(masthead) or 20-25%(fractional- these apply forestay tension too).

This should take care of forestay sag so when you hoist your genoa get it up tight enough to create the correct sail shape and doublecheck for sag as go along.

 

[Twister_Ken]

Bob,

Backstay tension takes out forestay sag, sans or avec foil.
Halyard tension moves genoa draft forwards.

Having a correctly set foil doesn't absolve you from winding on beaucoup de halyard tension if that's what conditions require.

Used to race a 41 footer with a calibrated hydraulic backstay tensioner, and we'd pump 5000 lbs per sqin onto it upwind inanything over about F3

 

[BobE]

Yes Ken,
That's what I remember from my racing days... So I was really surprised when the top swivel gave up the ghost... Seems that the circlip (a spiral one made of 25 thou stainless making a total of 50 thou) failed The current model uses a thicker circlip so mebbe it was a known problem...
So say I whack up the backstay to a measured tension ( I have already got a loos gauge) how on earth can I tell what to put on the Halyard?
I've already marked the halyard at what appears to be fully up and never get to the mark... All I can think is that the backstay has been to slack and I've been taking the forestay load on the halyard...Does that make sense??
Back in the 60's on Sunmaid V ( a 37 ) we used to actually jump on the coachroof mounted genny halyard winch handle to tension it... I remember that the handle screwed into the top of the Lewmar and the square section being weaker than the normal solid ones was deformed radially!
Now dear old Allegretto is only a 32 but I didn't put anything like that load on the little halyard winch just heaved like F..... by hand..
Of course Sunmaid had rod rigging and in those days hanked foresails..
Further commenta appreciated..
The parts are to be collected by me tomorrow so I might just cure this dose of "harbouritis" before Christmas..
Thanks for the input...
Cheers Bob E.........