Today, we had decent 10-13mph breeze, with a few gusts,so we rigged up & took the whole family for a an hour cruise. The old 5.7 still made pretty good time, even with 4 adults onboard.
About half way home I heard a bang, & saw the sail going quickly to leeward. My first thought was the mast was coming down. Luckily that proved not to be the case. The clew plate had blown completely apart, with a rain of rivets showering down on the tramp. It seems the heads all seperated, or sheared off.
Of course the multiple layers of sailcloth could not hold the hook, & it tore through, releasing the sail.
I undid the mast rotator line, & wove it into a bridle through through the remaining holes in the sail, so as to distribute the load, then placed the hook into the jerry rigged bridle.
This got us home, but better yet allowed us to pass the Albacore headed back to the same bay. Second place to an old Albacore would have been to painful to bear.
This was my spare (light wind sail, it's 10-12 sq ft larger than the original) & lightly used. The fabric is very crisp, the bolt rope shows almost no signs of wear, even the Skip Elliot decal shows almost no wear from folding etc.
It seems age & corrosion weakened the rivets to the point they failed under what I deemed a fairly light load. Upon inspection of the jib, I see two rivets missing the head.
My original 5.7 sail,(from a freshwater enviroment) despite seeing much more use, seems to have all rivets intact.
Luckily both sides of the clew plate landed on the tramp. I'm sending the piece containg rivet remains to a colleague in our fueselage structures shop for analysis of the rivets. I don't know enough about corrosion of aluminum to tell whether they failed due to load exceedance, or metal fatigue/corrosion.
I plan to get the guys who rivet skins in the fuselage dept to put it back together, using aviation rivets.
Can anyone tell me what, if anything needs to be done with the tear through the hole?
I'm thinking that it is the two plates fastened tightly together, gripping the material, that hold the load. The bit of fabric,(several layers thick) at the bottom of the hole doesn't do much?
Do the saltwater sailors see this sort of thing on a regular basis?
I have not operated Cats in salt water, & thought this sail would be as strong as new. Despite little previous use, it came from a salt water enviroment. I thought those rivets would not corrode, or is it more likely metal fatigue due to age?
I will certainly pay more attention to the head & clew plate fasteners from now on.
Edited by Edchris177 on Jul 19, 2011 - 03:42 AM.
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Hobie 18 Magnum
Dart 15
Mystere 6.0XL Sold Was a handful solo
Nacra 5.7
Nacra 5.0
Bombardier Invitation (Now officially DEAD)
Various other Dock cluttering WaterCrap
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