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Thread: Unstayed Carbon Mast for Small Boat

  1. #1
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    Default Unstayed Carbon Mast for Small Boat

    This is a cross post from Boatdesign.net. Sorry but I didn't get much of an answer.

    I'm looking for my next project.
    Current candidates:
    Bufflehead sailing canoe
    Mellonseed.

    I am looking for manufacturers of relatively short unstayed carbon masts. Probably 20' or less.

    Anyone have a suggestion? Or two?

    So far I don't want to build my own. Although I'm content that I "could" build a wooden birdsmouth mast.

    Thanks

    Marc

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    Default Re: Unstayed Carbon Mast for Small Boat

    What size are the masts on Roxanne or Romilly?
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: Unstayed Carbon Mast for Small Boat

    I don't know about those two boats.
    Until recently those are not boats I would have been interested in.

    But if those have been built with carbon spars, I can compare as soon as I get my plans.

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    Default Re: Unstayed Carbon Mast for Small Boat

    Ben Fuller just had one made for his Harrier. I'm guessing he'll chime in in short order.
    Quote Originally Posted by upchurchmr View Post
    This is a cross post from Boatdesign.net. Sorry but I didn't get much of an answer.

    I'm looking for my next project.
    Current candidates:
    Bufflehead sailing canoe
    Mellonseed.

    I am looking for manufacturers of relatively short unstayed carbon masts. Probably 20' or less.

    Anyone have a suggestion? Or two?

    So far I don't want to build my own. Although I'm content that I "could" build a wooden birdsmouth mast.

    Thanks

    Marc

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    Default Re: Unstayed Carbon Mast for Small Boat

    20' carbon sounds like a spinnaker pole.
    Heute ist so ein schöne Tag...

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    Default Re: Unstayed Carbon Mast for Small Boat

    A little bit of thread drift here.
    I costed a proposal for a home build budget blue water sailing cruiser a little while ago, and while the building skills, space and other issues pretty much meant hard chine plywood there was room in designing the rig to be a bit radical. We'd settled on a gaff sloop configuration. I did some research and proposed that the boat had, instead of a stayed rig, an unstayed carbon mast with running backstays to manage the forestay tension. The reduction in the number of fittings, stays etc more than paid for the cost of the carbon tube mast.

    I've since used the concept of a free standing mast with runners on other main and jib boats, and there are some interesting benefits, particularly on smaller cruisers and dayboats.
    Its very common for untoward things to happen when the main is pinned against the side stays, broaches, capsizes and so on. Also, when the main is able to be let out to 90 deg with the jib down the boat stops lying ahull with no way on. Note, thats not the best position in big waves, but its very handy when in confined spaces. There are other benefits, Howard Rice's SCAMP has proven the rig type, and that with a wooden mast.

    John Welsford
    An expert is but a beginner with experience.

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    Default Re: Unstayed Carbon Mast for Small Boat


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    Default Re: Unstayed Carbon Mast for Small Boat

    plans are from http://www.duckworksbbs.com/plans/bufflehead/
    info includes Hugh Horton who can help with mast making

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    Default Re: Unstayed Carbon Mast for Small Boat

    I really appreciate responses, BUT, I just said I don't want to build my own mast, and I have Bufflehead plans on the way.
    Additionally, Duckworks just says contact Hugh Horton - not much help there.

    I'm assuming that typical wood unstayed masts are tapered. So I assume the carbon mast would be tapered to work the same. So not a straight spinnaker pole.

    I just looked up previous Ben Fuller threads on Harrier's mast and will PM him if he doesn't show up soon. Thanks.

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    Default Re: Unstayed Carbon Mast for Small Boat

    Quote Originally Posted by upchurchmr View Post
    I really appreciate responses, BUT, I just said I don't want to build my own mast, and I have Bufflehead plans on the way.
    Additionally, Duckworks just says contact Hugh Horton - not much help there.

    I'm assuming that typical wood unstayed masts are tapered. So I assume the carbon mast would be tapered to work the same. So not a straight spinnaker pole.

    I just looked up previous Ben Fuller threads on Harrier's mast and will PM him if he doesn't show up soon. Thanks.
    Googling for windsurfing mast specifications produced a wealth of general and specific technical info.

    Various small boats have used them - varying means of attachement, including freestanding. seems thay's bee great for a sailing canoe as the righting moment is likely to not be the problem.

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    Default Re: Unstayed Carbon Mast for Small Boat

    There has been a lot of discussion of using windsurfing masts for sailboats.
    The typical conclusion is that a sailboat loads the mast more, and the mast is deliberatly more flexible to match the specific windsurfing sail.

    So I'm looking for one with higher stiffness.

    Several forumites say they have tried them and they always break. I'm assuming that would be the same for either of these boats.

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    Default Re: Unstayed Carbon Mast for Small Boat

    Take a look at http://www.cruisingworld.com/sailboats/escape-dinghy and see if this might be a good resource for you carbon rig.

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    Default Re: Unstayed Carbon Mast for Small Boat

    http://fortecarbon.com/marine/masts-booms/ I have had friends get masts from Forte, but don't know about the cost.

    a couple of other companies to talk to:
    http://www.offshorespars.com/masts/carbon-fiber-masts/
    http://www.seldenmast.com/index.php?id=4369

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    Default Re: Unstayed Carbon Mast for Small Boat

    I built Damfino's masts and building an unstayed carbon spar is neither simple nor inexpensive.
    The UFO foiler has a rig based on a windsurfer mast. Rigging supplies the needed stiffness.
    There's a good article on the boat in the current issue of Professional Boatbuilder mag.

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    Default Re: Unstayed Carbon Mast for Small Boat

    If you look here you can see Bufflehead with a carbon rig.

    http://forum.woodenboat.com/showthre...London-UK-2015


    Jamie Clay built the boat, but said the owner sourced the rig from the US. He modified the bottom of the mast to make the revolving cleat arrangement. It was a three part mast to come apart i think, i guess to fit in the boat.

    If I remember there is someone who makes a sail and carbon rig for Bufflehead in the US but I cant at the minute remember who it is. Hugh Horton would probably know. Note that some favour a batwing sail.
    Last edited by Edward Pearson; 04-17-2017 at 02:01 AM.

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    Default Re: Unstayed Carbon Mast for Small Boat

    This article and others is why I am asking about carbon masts.
    Horton was unwilling to continue an email discussion before I bought the plans.
    They haven't arrived yet.

    So there might be information with the plans, but he clearly said the plans provide geometry, but not building directions.
    With the combined experience of this forum, I had hoped for a simple recommendation, or someone who has built the boat.
    Fortus has been recommended but I am waiting for the plans and some geometry specifics before talking to them and any others.

    Hopefully I have a choice.

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    Default Re: Unstayed Carbon Mast for Small Boat

    Well, yes, I am building these 3-parts carbon masts for the Bufflehead sailing canoe, and a half-wishbone boom if needed. They do fit on other small boats as well. Self-promotion is not permitted, so please, send me a PM if you need more info.

    Cheers! Axel

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    Default Re: Unstayed Carbon Mast for Small Boat

    Folks,

    Chiming in. I did get my new mast from Tony Delima at Forte. I went up a half inch or so to get the stiffness I didn't have in the 2" 19' carbon mast that I got years ago from Ted Vandusen. Said mast needs a home and would be great for about 75 feet of lug or a larger sprit or gaff. PM me if interested. Tony uses the weaving system that Ted developed. Most of the inexpensive windsurfer masts are too flexible. A lug mast can't be too stiff as you don't want it to bend when you tension the rig. When the sail is laced or tracked to the mast, bending the mast flattens the sail.
    Ben Fuller
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    Default Re: Unstayed Carbon Mast for Small Boat

    Thanks to Ben and Axel.
    PM's coming.

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    Default Re: Unstayed Carbon Mast for Small Boat

    Not sure if you still need this http://uk-cherub.org/doku.php/tech/masts

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    Default Re: Unstayed Carbon Mast for Small Boat

    Windsurfer masts are all 4.7 m long or 15' 5" long. They standardized years ago and use base extensions to change lengths for different sails. They are also very flexible and usually aren't stiff enough for free standing in a small boat. They are usually strong enough, they just fall off to leeward so much that performance is very sub par. For something with next to no righting moment, this can be acceptable. So might be it might be OK for the Bufflehead , but not for the Mellonseed. The windsurf mast is much cheaper than all the alternatives because they are manufactured in huge volume by Chinese companies. A custom US shop will struggle to prep the mandrel for what the landed cost of a Chinese mast.
    The good news is that you can easily add reinforcement to the outside of of a windsurfer mast. There are a few tricks, but not much.
    Another alternative is to seek out your local rowing club or college crew and see what they have in the land of worn out oars. A sweep oar shaft is a great place to start if you want to build a gaff or standing lug rig.
    SHC

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    Default Re: Unstayed Carbon Mast for Small Boat

    Hwl,

    Not sure if I do or don't but it is very interesting.

    Thanks.

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    Default Re: Unstayed Carbon Mast for Small Boat

    OK, I'll bite.
    Do you have a reference to the "tricks" for beefing up a windsurfer mast?

    Quote Originally Posted by SHClark View Post
    Windsurfer masts are all 4.7 m long or 15' 5" long. They standardized years ago and use base extensions to change lengths for different sails. They are also very flexible and usually aren't stiff enough for free standing in a small boat. They are usually strong enough, they just fall off to leeward so much that performance is very sub par. For something with next to no righting moment, this can be acceptable. So might be it might be OK for the Bufflehead , but not for the Mellonseed. The windsurf mast is much cheaper than all the alternatives because they are manufactured in huge volume by Chinese companies. A custom US shop will struggle to prep the mandrel for what the landed cost of a Chinese mast.
    The good news is that you can easily add reinforcement to the outside of of a windsurfer mast. There are a few tricks, but not much.
    Another alternative is to seek out your local rowing club or college crew and see what they have in the land of worn out oars. A sweep oar shaft is a great place to start if you want to build a gaff or standing lug rig.
    SHC

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    Default Re: Unstayed Carbon Mast for Small Boat

    Don't waste your money trying to use a windsurfer mast on a different type of sail or rig. (home-brew stiffened or not). The only reason they even work on windsurfers is because they are pre-bent quite a bit using the outhaul to stiffen them and pretty much lock them into that shape. All it will do on a "normal" boat is guarantee you crappy performance just about all the time. It also makes the job of your sailmaker nearly impossible, simply because he has no good way to even guestimate what shape your free-standing mast is likely to have at any given time. Using one may look really convenient, cheap and like an easy fix, but it's a stupid rookie mistake.

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    Default Re: Unstayed Carbon Mast for Small Boat

    Todd,

    I recall your previous posts on this subject. That was what I was referring to about problems with windsurf masts.
    Even if you tried and succeeded in reinforcing the stock mast, the diameter of the mast has a bigger impact on stiffness than wall thickness, for an equal weight.

    Actually, I did not want to build one my self, although technical articles are always interesting.

    Do you have a source for such a mast?
    Again, I believe I could always build a wooden birdsmouth mast (or solid) but wanted to find out about the 20th century.

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    Default Re: Unstayed Carbon Mast for Small Boat

    Quote Originally Posted by upchurchmr View Post

    I'm assuming that typical wood unstayed masts are tapered. So I assume the carbon mast would be tapered to work the same. So not a straight spinnaker pole.
    I guess what I was trying to say was that at that size, people who make carbon spinnaker poles may be an option. Their autoclave would be the right size. And they may be cheaper, because their autoclave is not as big (and expensive) as a mast autoclave.

    They can make a taper, or not. You would have to discuss it with them. The purpose of the taper on a mast is to reduce mass aloft, where the strength is not needed. With carbon, the taper would come down to aesthetics. But not every carbon pole is straight. Wood poles tend not to be straight. Aluminum poles are an extrusion, and they tend to be straight as it's easier/cheaper to make them that way. Strange how our perceptions are now based on aluminum.

    Just trying to be helpful...
    Heute ist so ein schöne Tag...

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    Default Re: Unstayed Carbon Mast for Small Boat

    First, never built one, or even used carbon fiber, but a couple of points I've read:
    Daffodils withstand spring winds because they are stiffer to longitudinal bending forces than rotational ones, thus the weathervane.
    Years ago an Admiral's Cup racer, Crazy Koyote II, was designed with such a self-depowering rig. It did not race because the committee slapped it with a punitive rating.
    Back when Finn dinghies were sporting wooden masts, sailors would plane them down for optimum curvature and the saying was that it was fastest just before it broke.
    Can't wait to hear more.
    Good Luck

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    Default Re: Unstayed Carbon Mast for Small Boat

    I am very interested in this thread ever since inheriting a carbon mast that came from a Payson "Windsprint" hull that also came with a 113 sf balanced lug. The hull needed finishing so I tried the rig on my outrigger canoe. The carbon mast looked professional but has no company ID on it. It is 2.25 inch at base and tapers to the top, and though at first seemed stiff, I thought I noticed it bending under the stress of a balanced lug (both downhaul and gusts -- exactly opposite to what is wanted in a lug rig.

    Thus I thought perhaps this mast was meant for a windsurfer or a small non-lug rig, so I think my quest for a stayless carbon mast for this boat is complexified. Unstayed rigs for my need in an outrigger canoe are problematic because there is less stress relief on the mast due to less heeling.

    So, yes, interested in this thread. Some of the suppliers I looked into seemed heavy-duty cruising boat oriented. Forte Carbon looked promising, but I started wondering if at a certain price leve/ the simple aluminum T6 alloy tube seems best. Too bad they don't come tapered! -- Wade

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    Default Re: Unstayed Carbon Mast for Small Boat

    Quote Originally Posted by tom151 View Post
    Googling for windsurfing mast specifications produced a wealth of general and specific technical info.

    Various small boats have used them - varying means of attachement, including freestanding. seems thay's bee great for a sailing canoe as the righting moment is likely to not be the problem.
    --- Just be very careful about windsurfing masts unless you are using a windsurfing rig meant for them. I bought a pile of glass windsurfer masts years ago for a good price, but then used some for standing lugs in a cat-ketch rig; the masts flexed quite noticeably in gusts and under vang tension, but they never broke, will give them that (and they were great for various nonmasty things, such as outrigger side seats and safety ama cross-beams). Carbon will flex less, but flex it will unless proportioned for the task ( see my previous post) --just, do not assume unless you know your sail works well with a mast than can bend when unstayed. -- Wade

    [edit] OK, just saw Todd got in this already, above, though my glass tubes were straight (pre-pre-bend days???).

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    Default Re: Unstayed Carbon Mast for Small Boat

    Composite Engineering (composite-eng.com) or Forte (fortecarbon.com) are your best bets on the east coast for buying a mast that is designed for the job. Expect to pay upward of $1000. Forte makes rigs for the Byte and Maga Byte which are sold through Zim sailing.So they have a laminate schedule and diameter that works on boats about the same stability as a Melonseed.
    Kilwell FiberTube builds the raw tubing for many OEM spar buildershttp://kilwellfibretube.co.nz/ THey are in New Zealand, but if you buy a mast that sleeves together shipping is not bad. CST(cst-marine.com) is Australia. Both CST and Kilwell may build un-stayed rigs for other dinghies, and may have an off the shelf product you can buy.

    Todd's points are all correct. But..... you can stiffen up a sailboard mast to an acceptable level. Consider the sailboard mast as a mandrel that you are not going to bother to release. You will want to add about 2 mm of carbon fiber to the outside. This is done by laminatying 0 degree plies of unidirectional to the outside of the mast, compacting it with a spiral wrap and letting it cure. "Standard"300 g/m^2 carbon uni is about .014" per ply, so think in terms of 4 plies around the bottom 6' of the spar with a taper of several inches per ply. It is best to do this with the mast supported in a fixture that allows you to rotate it, and it is a good idea to have a helper to crank the handle you have fixed temporarily to one or the other end of the tube. We call this the Infinitely Variable Speed Voice Actuated Co-Magnon Digital Tape Wrapper. It works really well. After you have cured the laminate, you can test the stiffness by supporting it in a horizontal set of partners and hanging a weight on the tip that would be heavy enough to tip you over and measuring the deflection. If it isn't stiff enough , add more carbon and test again. If you want to help your sail maker out or just keep better track of what you are doing, take measurements at 1/4 heights. Once you have sonmething you feel is about right, sand the outside smooth and stretch a ply of braid over it to make it look nice. Soller Composites www.solarcomposites.com sells carbon braid by the foot. They also can supply the uni carbon either as flaty fabric or as a unidirectional sleeve with stretchy off axis fiber that is really easy to work with.
    When we built our own rigs years ago, we did things about like this to tune our masts for our weight, sails and sailing style. That is how I met Ted Van Dusen and started building carbon dinghy rigs in 1981. Carbon allows you to do what the masters did with wood masts, not settle for what is manufactured but tune it until it works perfectly. This isn't cobbling things together, this is custom building to a high level. Getting the mast right is like getting the centerboard and rudder right, it doesn't matter until you are next to another boat, and then it is very nice.
    SHC

  31. #31
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    Default Re: Unstayed Carbon Mast for Small Boat

    Quote Originally Posted by upchurchmr View Post
    There has been a lot of discussion of using windsurfing masts for sailboats.
    The typical conclusion is that a sailboat loads the mast more, and the mast is deliberatly more flexible to match the specific windsurfing sail.

    So I'm looking for one with higher stiffness.

    Several forumites say they have tried them and they always break. I'm assuming that would be the same for either of these boats.
    I am using windsurfer masts on my open sea going BayRaider for my -unstayed- topmast, mizzen mast, as well as for main, mizzen and jib booms. For near ten years, and in weather up to F8. Never broke one. They are as tough as nails if you take care of the main strain points.

    : If left unstayed, they need to be internally reinforced where they come out of the deck socket neck. Some round mahogany or teak piece approximately the inner carbon tube diameter serve nicely.

    Then, you can get windsurfer masts in many different lengths (my longest were 5.8 mtr), carbon content (do not buy more than 75% carbon!), different rigidity (Flex), and at least two different diameters (avoid the "skinny" sort.)

    Ideal for you purpose would be a 5.8mtr windsurfer mast with IMCS (flex value) greater than 32, 75% carbon, and with a core of teak wood inside, minimum 10" below and above the deck socket neck.

  32. #32
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    Default Re: Unstayed Carbon Mast for Small Boat

    I'm not really worried about the strength of windsurfer masts (although the wooden plug you are sticking in there makes one hell of a stress riser). They are simply too flexible for use with regular sails, and every time it flexes (or un-flexes) your sail's shape, draft, draft location and often also the entry angle and/or leech tension change. That's a really lousy formula for good performance, as well as being extremely hard to design a sail for. To those who say their re-purposed windsurfer masts work "just fine". I would usually say "Take a closer look with a critical eye" or just "Compared to what?" If somebody wants me to make them a sail for a sailboard mast, I just tell them to go away.

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    Default Re: Unstayed Carbon Mast for Small Boat

    don't know about your application,
    but the 'PT eleven' dinghy by PT watercraft uses a custom made unstayed carbon rig for its 58 sq ft sail.







    Reading their blog (i think i read that) they started out using modified windsurfing masts, but then went with the purpose-made setup...
    Maybe they would share some supplier info, or you could grab the whole kit at a cost of about $1350


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    Default Re: Unstayed Carbon Mast for Small Boat

    Quote Originally Posted by Todd Bradshaw View Post
    ... To those who say their re-purposed windsurfer masts work "just fine". I would usually say "Take a closer look with a critical eye" or just "Compared to what?"...
    : Compared to a custom made carbon rig for $$$$s.

    But otherwise agreed, flex of windsurfer masts is not always welcome. To avoid much flex, go for long windsurfer masts with high IMCS number (Indexed Mast Check System) as substrate for your rig.
    The higher the IMCS value, the stiffer the mast.
    If you take a long mast with high IMCS value, and then shorten that back for your specific length required, you achieve the best / highest possible stiffness. Years ago I did some practical tests for my own purposes, holding two 5.2 m windsurfer mast with IMCS 28 and 34 by their foot horizontally and hanging 4 kgs water bottles from the mast tops. The stiffer mast bent approx 20 cm over the entire free unsupported length, while the mast with the IMCS of 28 bent more than double that.

    The internal wooden plugs to reinforce the mast are for preventing the mast from sudden flattening and breaking at the stress point. (Like any hollow pipe would.) They also serve as foundation where you need to screw fittings like gooseneck on. C.
    Last edited by Craic; 04-18-2017 at 03:27 AM. Reason: added another happy Smiley.

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    Default Re: Unstayed Carbon Mast for Small Boat

    What a thread! Windsurfer masts have been standardised? Windsurfer masts have pre-bend? Windsurfer mast stiffness is adjusted by the outhaul? Err, no.

    Rick

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