Carbon or Aluminium Mast ?

[Nicholson58]

Race - carbon - for all of the obvious reasons.

Cruising - I stick with Aluminum. If the carbon spar breaks, it is usually catastrophic. Frequently a shattering and split. You are not likely to proceed. With Aluminum, you might be able to continue with a shortened spar. Also, I think you are less likely to injure crew with aluminum. I fails in a sort of ductile colapse rather than a shredding crack. If your boat is so rediculously light that you worry about weight aloft (probably racer anyway) you probably won't be comfortable cruising so follow your wallet or you hormones.

[s/v Jedi]

Assuming a high performance, fully roached mainsail, you do not need a taller mast. The designer of your boat has matched the rig with the size and weight of the boat already. One of the big advantages of high performance sails is that you can go with lower mast and thus easier to handle sail, easier clearance under bridges and less maintenance. Taller rigs are the opposite.

Also, when you start bolting aluminium hardware onto a carbon spar, you take away 50% of the advantages carbon brings. You need to use molded carbon fittings instead, multiplying the cost.

Lastly, carbon spars conduct electricity very well. You also get galvanic corosion.

ciao!
Nick.

[Matt Johnson]

Originally Posted by MacG

Carbon mast are already used (not widely) in one off's (not production boats as far as I know) so the benefit is there as long as it stays together.

I know at least Tartan uses carbon masts, but I'm sure other production yachts do too.

[Sand crab]

Eric Sponberg has a real interesting article on 4 mast failures. Some carbon, some lightning, some manufacturing screwups. Really detailed with great pics.
Four Mast Failures
I suggest a complete read of his site.
I have noticed an increase in the carbon fiber option on high end cats. If you got a cool mill to spend on a boat what's the big deal on another 50 Gs on a fancy stick?

[pbr]

When comparing aluminum to carbon for same moments of inertia you usually save at least 30% of the weight. Going to aramid rigging first is actually more productive relative to cost than changing to carbon mast. I have and never will buy into the concept that more weight aloft no matter what design is a good concept. To reduce weight aloft I would in order of priority go: rigging, sails, and then mast.

[pbr]

I will add the caveat that though a freestanding mast may be heavier overall it will have a lower CG than a conventional stayed mast, which is the pertinent number.

[jacob30]

The Freedoms have carbon fiber masts. They are a cruising boat. I looked at one and seemed like a great boat. The big downfall would be that if that mast breaks you are in for a really expensive replacement.

http://www.yachtworld.com/core/listi...url=&imc=pg-fs

[pbr]

Gary Hoyt was way ahead of his time, cf freestanding mast and the Camber Spar jib were great ideas then and still are now. Came standard with a rigid vang for twist control and all lines lead to the cockpit.

[captainbri]

The carbon fiber wishbone masts are pretty cool, Most of the website seemed to be defending carbon fiber masts and to me that was not a good selling point.

There are pros and cons to everything, I would stick with Aluminum but is is just a personal preference.

[MacG]

For the free standing mast, carbon might be a good idea. But there is a huge difference between carbon and carbon.
I have looked at the ad of Tartan boats, the explained that they use E (electrical) grade glass in unidirectional rovings combined with epoxy resin to reduce fattening and the chance on getting osmosis. Pretty cool system although I would use S-glass instead of E. I have experimented with a combination of titanium and carbon, the two materials bond quite well but the mastbuilders have no idea about exotic metals and are reluctant to make a life sample. I builded myself a mastsection of titanium wiremesh and a batch of carbon used in the B2 bomber.
In aluminium you can work with sections, with carbon you cannot. You must make the mast in one piece and in an uninterrupted process. That and the basic material makes the top-quality carbon masts quite expensive. Carbon is just a generic name. To talk about the material you must name horse and number and calling the material plus matrix with the correct tag. Otherwise this sort of discussion renders useless.

[delmarrey]

titanium and carbon, the two materials bond quite well

Can you give more detail.
I've machined a lot of titanium but didn't think epoxy would bond to it very well. Never tried myself. I've made a large rudder shaft for a colleague's 43' sloop but assumed he uses a 3M sealer between the shaft and epoxy as I do with SS and epoxy.

[Jim Cate]

Originally Posted by Sand crab

Eric Sponberg has a real interesting article on 4 mast failures. Some carbon, some lightning, some manufacturing screwups. Really detailed with great pics.
Four Mast Failures
I suggest a complete read of his site.
I have noticed an increase in the carbon fiber option on high end cats. If you got a cool mill to spend on a boat what's the big deal on another 50 Gs on a fancy stick?

G'Day SC,

Thanks for that link... a truly interesting piece! I think that all of you guys arguing about this subject should read it, for it is written by someone who actually knows something about the subject and expresses his knowledge well.

I was particularly interested in the two examples of lightning strike damage on carbon rigs, and in the "lightning arrestor" that is shown as the latest thinking in that arena. Quite the opposite of the "witches broom" ion dissipators that many use.

Cheers,

Jim

[MacG]

Originally Posted by delmarrey

Can you give more detail.
I've machined a lot of titanium but didn't think epoxy would bond to it very well. Never tried myself. I've made a large rudder shaft for a colleague's 43' sloop but assumed he uses a 3M sealer between the shaft and epoxy as I do with SS and epoxy.

Titanium bonds extremely well with carbon because the metal is almost inert.
There is the general alloy TiV6 the most widely used, there are also many other alloys but for general use the TiV6 works fine. Carbon in general has no effect on Titanium, the racing crowd uses therefore titanium for the connecting parts for the rigging.

The reason that carbon can give all in a sudden way is to be found in the way the layers are build up and the frequency of vibration. One thing carbon doesn't like.

[pbr]

Mac you generalize way too much, there are all kinds of processes, spun filament on a mandrel, female mold, wet layup, pre-preg, etc To right off carbon fiber masts as iffy in this day and age is rather absurd, look at the 25 year old Freedom mast referred to earlier, old technology and still going strong. That mast today could be just as strong and probably 20% lighter.

[delmarrey]

I've been contemplating building/install a yoke about 7'- 10' back from the bow for a bridle setup for use in anchoring or sea anchor. It would pass thru the hull just under the deck and aft of a bulkhead.

It needs to be water tight so stainless was out of the question but did consider CF as a possibility. If titanium adheres to epoxy as you say, that would make a better choice. Or even CF over Titanium.

As an retired toolmaker I tend to think out of the box a lot and experiment, with pretty good success.

But back to Masts!

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