Hollow 12 sided wooden bird’s mouth sailboat mast covered with a woven biaxial carbon fiber sleeve
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- čas přidán 20. 08. 2024
- Mast I built for my Slingshot 16 Tandem Trimaran designed by Frank Smoot plans are available on Duckworks. Sail is 107 square foot leg o mutton with a loose footed boom. Sail made by Poly Sail International.
Nice looking job. Also - jealous of your shop tools.
That is down right beautiful.
Great job! Can't wait to see it sail.
you are a champ well done
great video. Did the carbon fiber stiffen it up some? Looked kind of flexible when just wood.
Thanks It did stiffen it up a lot but it still has a good amount of flex but nothing like it did in the video.
Tks, I guessed you're using pine wood. I confess, I'm quite skeptical using pine... maybe here in Brazil the pine is different... look the same but I'm not sure about the resistance, the stress of the bending.
Great job in describing the process. I'm particularly interested in the geared motor that was turning the mast during the post-processing. Is that something you bought ready-to-go or did you make it up? I could really use something like that in our shop.
Thank you. It’s a gear 12 volt head motor that was originally used to swing out a stop sign on a school bus. Grainger sells them in various rpm’s and voltages. Depending on water your doing you might be able to use one of those tumbler or coffee cup spinner’s. Go with the slowest rpm you can find probably less that 10.
Did you think of a expandable foam inside the mast? displaces moisture and stiffens a bit more.
Never thought about it. Sounds like a good idea. Thanks
Pretty cool project. How much does the mast weigh? I'm building a Farrier F22 trimaran and I've been trying to figure out how to build my own mast for it. Maybe I could use this technique. I think the Carbon sleeve would work well, but I think it would need a few layers of unidirectional as well.
It’s about right at 20 pounds. It does flex quite a bit but it’s proven to be very strong. I’m sure if you added more layers of material would stiffen it significantly. Also increase the thickness of the wood. Wall was about 5/16” thick on this mast. Pretty thin.
Good stuff, so aprox weight per ft after laying the carbon fiber & epoxy?
I’m thinking it was about a pound per foot. I gifted that boat to another club member or I would weigh it for you. The staves were about.300 thick. It flexed quite a bit so I added rope stays but its still going strong.
Will, that looks great! Appreciate you sharing the process. How much did the mast way before hardware?
I didn’t weigh it before but I’m guessing 21 pounds. It was an interesting project.
Nice build. What's the total length? Is it tapered? How many layers of carbon fiber did you put on?
Thank you. 22 feet 4 inches tall. Yes it’s tapered and one layer of carbon. 2 layers on the bottom 2 feet.
Oh dear, firstly you missed out showing the only difficult bit, gluing up the wood and getting it assembled and clamped up. Then the most useful technique with sheathing, vacuum bagging.....
I truly wish I would have done a better job getting more video for sure. Should have took the time to set up Timelapse of the assembly. It was not easy. No vacuum bagging on this project. Just used the rotisserie to get an even application of epoxy.
do you think it could be done with divinycell instead of wood? building each half and glassing both sides... then gluing both sides...
I’ve never worked with that material before. I’m sure it could be done but not for sure if it would be good for a mast. Would be a neat experiment.
Nice build, do you have a jig for the 24 or 12 taper pieces?
Thanks. No jig it was a router bit I purchased off Amazon.
Good evening. Which wood did you use? Which software to calculate the sections. Tks
Select pine from the hardware store. I used Duckworks birds mouth calculator.
What is the motor you used to turn the mast when applying epoxy to the carbon fiber?
It’s a 12v gear head motor I salvaged out of a school bus stop sign. Grainger sell all kinds of these motors in various voltages and rpm’s. I got the idea from my wife she makes drink tumblers and coffee cups and she uses a similar device when applying epoxy.
How to you prevent water intrusion through the holes at the top?
The masthead is a hardwood plug separate from the hollow mast. Keeping things water tight.
Can you provide a link to the mast design program?
The only thing I used was Duckworks Birds-mouth Calculator. www.duckworksmagazine.com/04/s/articles/birdsmouth/
Fill it with hard foam, coat it with polyester Fiber epoxy
I never thought about filling it with foam.
🤔 unless you completely seal the inside of the mast. It will definitely rot from the inside out.
Your correct. There are parts of this I didn’t video because it was difficult to do by myself. I did lay all of the staves flat and roll epoxy on the inside portion before assembly. The test mock-up tube I did not. Things got really busy when it got assembled. Time was not on my side but we pulled it off. I highly recommend a helper when doing this type of project.
What was the software that you used
www.duckworksmagazine.com/04/s/articles/birdsmouth/
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Carbon fibre is toooooooo stiff
It’s to late. It’s a done deal.