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  1. #1
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    Sep 2009
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    Default Cement and chicken wire

    when I was young I inherited a book from my older brother about boat building (wish I still had it as I am now looking to build a kayak.) and in it there were plans to build a kayak out of a certain type of cement (not the normal blue portland variety) and chicken wire. has anyone got any info regarding this? Also as I have just stated I am looking at building my first kayak and as much as I would like it to be one of those clear skinned wonders with a tidy looking timber frame beneath, or even a 12 foot percy blandford design, I am planning to go the stitch and glue method. I have the plans from JEM watercraft for their laker 13 footer. What I would like to know is if anyone has built this particular craft and if so how it went.

    As I say I live with the dream of one day in the not too distant future building a canvas over frame, but for now I think a stitch and glue would be a good intro. I have paddled plastics fibreglasses and canvas craft and the canvas are just better in so many ways than the plastics and fibreglasses. I have a cousin who when I was about 13 or 14 lent me one for stint on the murray river and was so impressed by it I have wanted one ever since.

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  3. #2
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    Feb 2009
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    Adelaide - outer south
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    Hey Travis are you looking for someone who built one of these.....



    Don't know of anyone around here .........except Hairy Mick and myself.

    There are a few other aussies in the builders log section of the Jem site - John the Pom and Cridgie spring to mind - but I can't specifically remember any in Vic. Wouldn't be surprised if there are some though as this is a popular design.

    This was my first build and apart from a fiasco in the hull glass layup (because I decided not to follow the instructions ) it all went smoothly. The construction method is very forgiving and can give a strong lightweight hull if you pay attention to detail.

    I would like to make 2 points from my experience -

    1) - buy good quality ply. I bought cheap stuff and although I think I have a good boat I reckon it would have been even better if it was made of 3mm gaboon marine ply.
    This photo shows the voids in the ply (in my finished kayak) that show up when I put a 120w floodlight inside the hull at night. The horizontal lines are joints but the smaller ones running vertically are voids in the ply.



    The boat is still sound but I would feel better if these voids were not there.

    2) Take great care in marking out the panels and USE THE QA DRAWINGS. If you take twice as long as you should then it is time well spent if it allows you to get this bit right. As I said earlier the method is forgiving but a big mistake will require rework/extra work or make an inferior boat. If the panels are right the rest will flow

    Start builder's logs here and on Jem, update them often and you will have the support of dozens of experienced advisors - worth it's weight in gold but it's free!

    Good luck with it, looking forward to following your progress.
    Cheers, Bob the labrat

    Measure once and.... the phone rings!

  4. #3
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    Feb 2008
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    Eustis, FL, USA
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    Default

    The method you refer to is called ferro cement construction and a hugely critical element of it's success is the "wire armature" used internally. It has to be high quality, welded wire, and please not chicken wire. This mistake had been made countless times and as a result of it, people have died and the reputation of this method (which if done properly is fine) is considered the worst of all methods. It's in fact so bad in the USA, you just can't sell a ferro cement boat.

    This is partly because you can't "survey" the structure without extras or ultrasound, but mostly because of the terrible reputation it wears.

    In a canoe or kayak in this method is possible, but requires the most judicious use of expertise and materials that can be imagined. The resulting ferro skin will likely be less the 6 mm in most places and very flimsy if the "wire" isn't done right. In order for this method to produce a light weight boat, it has to be done "by the numbers" or you'll have a garden planter on your hands.

    Personally I don't think it's a reasonable method for the backyard builder in sizes under 30' on deck, but it can be done.

    The JEM Laker 13 is a fine little beginners boat, considering it's shape and design considerations. If you've purchased the 13' plans you'll find the forward sections slightly different then the free 13' kayak plans they offer.

  5. #4
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    Quote Originally Posted by labr@ View Post
    Hey Travis are you looking for someone who built one of these.....



    Don't know of anyone around here .........except Hairy Mick and myself.

    There are a few other aussies in the builders log section of the Jem site - John the Pom and Cridgie spring to mind - but I can't specifically remember any in Vic. Wouldn't be surprised if there are some though as this is a popular design.

    This was my first build and apart from a fiasco in the hull glass layup (because I decided not to follow the instructions ) it all went smoothly. The construction method is very forgiving and can give a strong lightweight hull if you pay attention to detail.

    I would like to make 2 points from my experience -

    1) - buy good quality ply. I bought cheap stuff and although I think I have a good boat I reckon it would have been even better if it was made of 3mm gaboon marine ply.
    This photo shows the voids in the ply (in my finished kayak) that show up when I put a 120w floodlight inside the hull at night. The horizontal lines are joints but the smaller ones running vertically are voids in the ply.



    The boat is still sound but I would feel better if these voids were not there.

    2) Take great care in marking out the panels and USE THE QA DRAWINGS. If you take twice as long as you should then it is time well spent if it allows you to get this bit right. As I said earlier the method is forgiving but a big mistake will require rework/extra work or make an inferior boat. If the panels are right the rest will flow

    Start builder's logs here and on Jem, update them often and you will have the support of dozens of experienced advisors - worth it's weight in gold but it's free!

    Good luck with it, looking forward to following your progress.

    That is a really nice looking boat, Wanna build mine...lol. you say that you skimped out a bit on the timber, does this mean that you used the Luan or merantii ply that most timber yards or large hardware stores stock?

    I haven't bought the ply or anything yet, as I was wanting to see and hear from other people who had made one first. where I would be doing a lot of my kayaking is in small streams and rivers where at times there is probably less than 6 feet of width to them and at times not much more than 6 inches of water (generally a couple of foot to 6 foot but unnaccesible by any means other than a canoe.)

    This leads me to the question how deep do you find it drafting? I weigh approx 90 kilos and would want to be carrying with me probably 20 to 30 kilo of kit (Comprising of a gold pan, small pick, shovel, first aid kit, and maybe a small sluice, and enough food to get me through lunch etc.) do you think it would handle this sort of load without too many problems?

    Even though as you say you can see the voids in the ply you got a really nice boat and I hope that I can build something 80% as good. it looks #### hot, Job well done. Oh and by the way I am led to believe that epoxy is approx 200 times stronger than the timber and thus the timber is only there as "body" so to speak, so I doubt that the voids will ever cause a problem

    Thanks Travis

  6. #5
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    Default

    Quote Originally Posted by PAR View Post
    The method you refer to is called ferro cement construction and a hugely critical element of it's success is the "wire armature" used internally. It has to be high quality, welded wire, and please not chicken wire. This mistake had been made countless times and as a result of it, people have died and the reputation of this method (which if done properly is fine) is considered the worst of all methods. It's in fact so bad in the USA, you just can't sell a ferro cement boat.

    This is partly because you can't "survey" the structure without extras or ultrasound, but mostly because of the terrible reputation it wears.

    In a canoe or kayak in this method is possible, but requires the most judicious use of expertise and materials that can be imagined. The resulting ferro skin will likely be less the 6 mm in most places and very flimsy if the "wire" isn't done right. In order for this method to produce a light weight boat, it has to be done "by the numbers" or you'll have a garden planter on your hands.

    Personally I don't think it's a reasonable method for the backyard builder in sizes under 30' on deck, but it can be done.

    The JEM Laker 13 is a fine little beginners boat, considering it's shape and design considerations. If you've purchased the 13' plans you'll find the forward sections slightly different then the free 13' kayak plans they offer.

    You say that the forward sectoins are a bit different on the bought plans compared to the free plans, in what way? and do the differences make a big difference on the water?

    I have a few ideas on how i would modify the front end slightly and was wondering if I was on the right track or not.

    As for the Ferro cement I wish I had photos of the huge ferro cement boats built by a bloke near Port Lincoln in south australia one would be about a 40 foot yacht, which is a finished hull and the other would be at least 5 times the size, unfinished. These are just sitting incomplete a long way up the hill from the harbor but the work that has gone into them is awesome. I don't know if the maker ran out of money or whether he passed away, but I believe that most builders on here would be in awe of them.

  7. #6
    Join Date
    Aug 2008
    Location
    Melbourne
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    Default

    Travis,
    you might find this of interest.
    http://www.ferroboats.com/

  8. #7
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    Jul 2005
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    'Delaide, Australia
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    Default

    Howdy,

    During the era when concrete boats had some popularity a lot of non boatbuilders were tempted to try them.

    The big problem was that they thought the hull was cheap so they would have a cheap boat so often chose quite large ones. Much larger than someone building of any other material would choose.

    Problem is that the cost of the hull shell in any material is just about the cheapest part. And choosing to build a bigger boat commits you to bigger expenses in all the other bits. A worthy lesson for all boatbuilders!

    Very large unfinished concrete boats sitting in the landscape for many years became quite common during the 70s.

    A couple of pro builders in New Zealand had a specialty in very high quality Concrete boats in the mid 30 foot range. You could not easily tell the difference between them and a production 'glass boat.

    Best wishes
    Michael

  9. #8
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    Feb 2009
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    Adelaide - outer south
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    Travis,

    Happy to build yours but I don't think you'd like the labour charge!
    Actually mine doesn't look quite that good close up - you'll do just as well.

    Regarding the ply: I selected mine from a wholesaler's web site and ordered it through a local hardware store. presonally I think external grade would be fine in most cases but will never be quite as good as the "proper" stuff. Don't think the ply is unimportant - if you use thinner ply of low quality but then have to apply heavier glass then you will end up with a heavier boat. Mik is a keen supporter of the "more timber less glass" theory and I agree with him. I used 84gsm (approx 2oz?) glass on my Laker and I think it's fine. If you are going prospecting in rocky rivers then you may want something heavier for abrasion and puncture resistance.

    Regarding capacity: I think the Laker will be fine for what you want to carry. Think out your hatches etc before the build and have a look at the builder logs on Jem for ideas and to see what works. Hairy Mick would be a good person to ask about this as he is near the upper recommended size limit for this boat. I am on the small side and have so little draft that I get blown away from other kayaks when stopped for a chat on the water!

    Regarding differences between the free and bought Lakers: Matt (the designer) told me that almost every panel is different - but not by much. The hull is symmetrical so front and rear panels are identical. Building instructions are the same.

    Also I just remembered there's a builder in Melbourne called Olsnapper - he may be able to help with material sources in your area.
    Cheers, Bob the labrat

    Measure once and.... the phone rings!

  10. #9
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    skimping on material is not really on the cards, was just wondering what you used. If I do build the laker I would probably go a combination of build option one and two with the 6 mm ply for the hull, 4mm for the sides and deck, taped seams and then fibreglass sheet the hull up to the joints of the sides. Granted this would be quite heavy but should be considerably more durable and "safe" for rocky creeks etc. I think this would also be better for teaching my youngsters how to paddle a 'yak. I would really like to build something along the lines of a PBK10 and may still go down that path yet. I have had a look at the yostwerks.com website and although the boats on there look very nice I would like something a little wider than what they offer as far as plans go (I dont plan on doing too many barrel rolls, and I am a fairly large guy at 6ft 8 and although I am not fat I would need at least 20 inches of opening to get my backside into the boat easily.) This is sort of what has led me to plans like the laker, the PBK 10 and 27 etc. because I want something easy paddling both for myself and the missus and for the young fellas to have a go at in a few years. This said I also want to be able to get into some fairly confined areas so I need something as compact as possible length wise. I COULD go to Rays outdoors and buy a Plastic kayak for about 4 to 500 dollars but I dont want a plastic, and I have the technical knowhow and tooling to be able to build what would cost me a lot more than that for around the same cost in materials. The labour as we all know is gratis and isn't really labour so much as doing something we enjoy and can see the reward for at the end of it. Here in victoria we have about 3 months more poor weather so it will give me something to do in the shed on weekends and evenings, and quite frankly I dont care if it takes till after christmas to complete the project. this said I would like to be out paddling quite a bit in late summer early autumn.

  11. #10
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    adelaide
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    Default cement boats

    From the little i know about cement boats one of the drawbacks is that if the job is not completed in one go and the wire sealed in before it has a chance to rust it inevitabley goes rusty inside, at least timber cant rust and if kept reasonably dry work can progress in stages over several years with no corrosion to worry about, peter

  12. #11
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    I don't think that's right.

  13. #12
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    Ferro boats do have to be "cast" in a single pour, but not because of the wire armature. If not cast in a single shot, then the seam will leak from water pressure. The steel in the armature usually does rust, unless special measures have been taken, like zinc coating the wire mesh before the pour. This rusting is one of the biggest issues with ferro cement construction, both in value, durability and most importantly evaluation for sale or insurance.

    Concrete pools are also done in one big continuous pour as well, for the same reason, it'll leak if it's stopped and started.

  14. #13
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    Par is spot on, however with the "Sayer's Method" you plaster ALL the outside then ALL the inside of the hull but with no joins in either coat. With regards rusting, ferro-cement (also called SRP-steel reinforced plaster) boats should be treated the same as a steel boat, ie; correct anodes, placed properly and consideration given to boat's environment
    (eg: neighbouring boats, shore power, pylons, seabed, etc).
    Most of these boats were were built outdoors, so they may remain exposed for some time before plastering. I suspect rusting usually occurred after they were built.
    I'm a solid plasterer by the way, sand and cement are my thing.

  15. #14
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    Going back a few years (80s or maybe even late 70s) there was a concrete canoe competition/race held overseas. I think it was somewhere in Europe but could have been USA. An Australian team entered but had trouble transporting their craft so came up with a design to make transport easier which also made it lighter and hence better performing. The reinforcement was a fine wire mesh, probably similar to flyscreen in dimensions, and the cement was forced into this with a trowel on a flat supporting surface. This gave a series of very thin flat hull panels that only needed to be joined at the seams. The panels were simply rolled up and placed in tubes for travelling.

    Travis, have you started your build yet?
    Cheers, Bob the labrat

    Measure once and.... the phone rings!

  16. #15
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    G'day Travis

    SA Uni engineering students have competed in a concrete canoe race for the last few years.
    Possibly against Flinders or Adelaide Uni.
    Design & build brief.

    Might be able to get info from them if you really want to do a concrete canoe.
    (Concrete seems to me to defeat the purpose of a canoe - small, light, portable, etc, etc...)

    cheers
    AJ

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