While impatiently waiting for spring, I started a carbon fiber mast for my Skerry.
I'm just playing but its an interesting exercise.
All I've done so far is work on the core. I should start to layer carbon fiber this week.
I would love to hear from others who have worked with this material.
I found a combination carbon fiber and kevlar on sale so that is what I will be using, but I'm not so sure how thick the build up should be.
Fun while its below freezing in Toronto.
Christine
Christine,
I built a carbon fiber mast and sprit for my brand-x sailing dinghy. I used "sock" technology. That is, tubes of material pulled over the mandrel, rather than sheets rolled around it. I used 2 different styles of building for the mast and the sprit.
The mast has a 2-inch diameter core made of pipe insulation foam. The ends and the area where the mast passes through the partner are reinforced with glass tape. The layup schedule for the mast is biaxial glass, linear carbon fiber and biaxial glass again. The pipe insulation (a closed cell foam) stayed inside when the mast was done. The top of the mast is plugged with glass and wood putty and has a stainless steel eyebolt (the same as the Skerry, in fact, I got it at CLC)to anchor the lashings. The mast came in at 2 lbs without paint and without fittings.
The sprit is 1 1/4 inches in diameter. It was mainly an experimental piece, testing several different ideas and a new supplier of materials. It ended up way overbuilt and about the same weight as wood. Same general idea as the mast - linear CF sandwiched between biaxial glass. It's hollow with wooden plugs at each end. The nose is a dowel shaped to fit the peak loop in my sail, while at the knee the wood is entirely within the mast and acts to reinforce the mast for a hole for the snotter
For fittings I put a wooden collar on the mast with dowels that act like fixed belaying pins (they're recycled from CLC disposable foam brush handles).That way I didn't have to drill any holes in the mast.
The epoxy should be a high modulus one, like Silvertip or its equivalent. The main trouble I had was getting the work off the mandrel. Pieces of pipe, conduit, etc. have tiny irregularities in shape that are harmless in short lengths, but when extended to 10 feet or more make it impossible to get the work off the mandrel without cutting something. A foam core works much better (either pipe insulation or 2-part structural closed cell).
Cores and mandrels also like to flex. The easiset way I've found to make a straight mast is to hang the core vertically and work with gravity, instead of against it. That does need a tall shop and/or short masts, though. I'm planning a 21-foot mast later this year. That'll be hung from a tree once the great outdoors warms up again.
The early stages of my mast construction are at Krakenbait Gets a Carbon Fiber Mast. Now that the boat is finally finished, I need to go back and finish updating the mast pages.
Good luck with yours, they're a lot of fun.
Laszlo
Hi Lazlo
Great information thank you so much. I had many questions after reading your web pages on the subject.
I was not able to get my hands on affordable sock material in Toronto. Since I'm not really "needing" a new mast I could not justifying the expense.
Here is a link to the page on my boat web site. You will notice that I link to your mast pages in the research page.
http://www.christinedemerchant.com/carbonmast.html
All the best
Christine
I've had the pleasure of sailing in the Krakenbait and am impressed with the carbon fiber mast and sprit Laszlo made. The lightness of the rig is incredible surprising. Can't wait to see you build the 21 footer, Laszlo!
Christine, looking forward to seeing your results as well.
George K
George,
Thanks. Just waiting for some progress on the hull before I commit to the mast & rigging :-)
Christine,
Thanks for the link. Wow! That's low production rate tooling you've turned out there. You do good work. Soller's Composites is a good source for reasonably priced CF, including socks. I don't know what your budget is, but they also have deals and since they're up in New England the shipping should be reasonable.
I love the Static Guard idea, that's brilliant. Every time I've worked with foam it's been a blizzard.
Do keep us posted,
Laszlo
Hi Lazlo
It seems that shipping across the border is always expensive plus Revenu Canada or whatever they call themselves currently, takes a bite for duties and taxes.
What kind of boat is Kreken Bait? She's pretty. I guess you're not too superstitious. What 21 footer eh?
I have an ulterior motive in making this mast. I plan to build a new larger boat. Iain Oughtred's Ness Yawl. I hope that I can make a mast, use it on my Skerry and work out the kinks then just use it on the new boat. The mast should be about 16.5 feet.
I love my little Skerry, first love you know. I can't think of a better first boat, It does everything. But I would like a boat that can deal with the sometimes nasty mood swings Lake Ontario throws at me.
Had a slight setback. When I took the plastic off I realized that I had tightened it too much and the 2 halves had slipped a bit and did not meet perfectly on edge. No technical problem but not so pretty.
Started again but this time I will assemble the halves with toothpicks or skewers laying across so that the halves dont slide past each other.
Its really amazing, the tube I ended up with is very rigid already with just the 1-2 layers of fiberglass. Weights nothing too.
I might just use those for lug sail spars.
Cheers
Christine