RE: [AlbinVega] Headsail only in strong wind

[roy]

I do remember reading about column collapse.
I believe boats with fractional rig are more prone to it.
What happens is that when you have the mainsail up, the whole luff edge is pulling on the mast to aft. The fractional forestay is pulling on the mast to forward.

So when you totally remove the mainsail force, the only remaining force is the forestay pulling on the midsection of the mast and the backstay pulling from the top of the mast....
Then you get a buckle at the midsection when you get a gust or you go over a big wave and the boat lurches.

There may be other ways for column collapse. I am definitely not an expert sailor.

rb

 

[Vega1447]

Thanks Rob,
so it looks like a masthead rig like the Vega is less vulnerable to this??

All the best,

John

Vega 1447 Breakaway

John A. Kinsella Ph: +353-61-202148 (Direct)
+353-61-333644 x 2148 (Switch)
Mathematics Dept. e-mail: John.Kinsella@...
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[groundhogyh]

You're making me work here

I'm not an authority for sure. There are a bunch of ways for a mast to break from what I am reading.

I have a copy of Alard Coles Heavy Weather Sailing.
Page 46.

Other ways stated are repeated mast flexing from untuned rigging. This will work harden some point in the mast and it will become brittle and weak.

Where the rigging attaches, there are several types of attachment designs. Some are weaker designs than others. If one of the rigging wires snaps off, you can mis-load the mast and cause failure.

Another one is that in a full masthead rig, if you reef the main, you are now pulling more on the midpoint of the mast toward the stern. Again a big puff or lurch and you might buckle the other way.

"Generally most boats are adequately stayed in the athwartships plane. It is achieving sufficient fore-and-aft support that causes most problems. Beating into a heavy seaway with a deep reefed main can be one of the most punishing situations for a mast. High shock loads transferred through the rigging, as the boat pitches and slams through each wave can cause the mast to pump fore and aft..."

So it looks like both masthead and fractional rigs both have thier weak points depending on how you have your sail plan up.

Roy