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Old 22-01-2016, 09:25   #16
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Re: carbon fiber masts

Just again coming from aircraft CF isn't very damage tolerant, a nick or scratch and you get a stress riser and that leads to a fatigue failure, plus how do you attach anything to it? Cushioned clamps would I guess be the answer. But if anyone is wondering about strength / flexibility, look at a CF fishing pole, we have all seen them bent double without failure
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Old 22-01-2016, 13:30   #17
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Re: carbon fiber masts

Going Walkabout,

Currently I own one carbon mast, and two alumnium masts. I have also had an aluminium mast struck by lightning.

There is no question that if you get hit you could have substantial damage from a lightning strike, but wether the mast itself is damaged is an open question. In our case the copper conductor took the brunt of the hit but everything electrical was still fried on the boat. Had it been a carbon stick I am pretty sure that the same thing would have happened.

My basis for arguing that CF is no more likely that aluminium to suffer lightning damage is that insurance companies don't charge different rates based on the material of the mast. They likely do charge for the price of replacement, but not its construction. If there was a statistical difference in the damage likelihood between them it is the insurance companies that would be the first indicators.
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Old 22-01-2016, 17:12   #18
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Re: carbon fiber masts

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Originally Posted by Stumble View Post
Going Walkabout,

Currently I own one carbon mast, and two alumnium masts. I have also had an aluminium mast struck by lightning.

There is no question that if you get hit you could have substantial damage from a lightning strike, but wether the mast itself is damaged is an open question. In our case the copper conductor took the brunt of the hit but everything electrical was still fried on the boat. Had it been a carbon stick I am pretty sure that the same thing would have happened.

My basis for arguing that CF is no more likely that aluminium to suffer lightning damage is that insurance companies don't charge different rates based on the material of the mast. They likely do charge for the price of replacement, but not its construction. If there was a statistical difference in the damage likelihood between them it is the insurance companies that would be the first indicators.
Maybe, maybe not. The fact is there are still very few carbon spars out there, and lightning primarily damages electronics, but secondarily structures in a mode that is often difficult to predict. If I was looking for answers (and the OP is!) I would look for the answered questions in an extremely high value and failure sensitive industry, namely the aviation industry. It is quite clear from the comprehensive lighting strike testing in this context that carbon is much more vulnerable to lightning strike than is aluminium, to the extent that these multibillion dollar corporations with millions of passengers in a safety critical situation have decided to put an aluminium weave throughout their carbon composites… not an easy thing to do. Do you have some other intelligence on the issue?
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Old 23-01-2016, 13:39   #19
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Re: carbon fiber masts

Researching further I have discovered drilling through the epoxy into the carbon causes a point of electrical penitration. It is this point of entry by lightening that does the damage. If hit the CF has been known to explode and dramatically disintegrate. Other times no damage is obvious from visual inspection since the carbon is basically wrapped in epoxy hiding damage. This explains the cases of masts coming down time after the lighting strike.

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Old 23-01-2016, 15:06   #20
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Re: carbon fiber masts

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hi all I am looking at a freedom 39 pilothouse schooner rigged with carbon fiber masts. I was wondering if anybody had any experience with them and the pros and cons . to my inexperienced eye it looks like a clean and simple rig. thanks

I have the express version of the F39 (same hull as pilot house but a cat ketch rather than a schooner) and have no concerns whatsoever with the CF masts. Both of my masts were replaced about 10 years ago by the previous owner under an insurance claim resulting from a lightning strike.


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Old 23-01-2016, 18:47   #21
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Re: carbon fiber masts

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Originally Posted by Muckle Flugga View Post
Maybe, maybe not. The fact is there are still very few carbon spars out there, and lightning primarily damages electronics, but secondarily structures in a mode that is often difficult to predict. If I was looking for answers (and the OP is!) I would look for the answered questions in an extremely high value and failure sensitive industry, namely the aviation industry. It is quite clear from the comprehensive lighting strike testing in this context that carbon is much more vulnerable to lightning strike than is aluminium, to the extent that these multibillion dollar corporations with millions of passengers in a safety critical situation have decided to put an aluminium weave throughout their carbon composites… not an easy thing to do. Do you have some other intelligence on the issue?
Ya, it isn't like almost every high end production boat uses cf, or almost all race boats, or every super yacht. It isn't like almost every sailboat over 80' built in the last 10 years hasn't used CF.

This isn't exactly a new idea. CF is a very well understood and reasonable alternative. The only real downside is the initial cost, which is certainly an issue with entry level products.
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