The use of basalt fibres in boat building

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  • 03 Apr 2020 13:49
    Reply # 8876856 on 8873098
    Anonymous wrote:

    That's very interesting Jim. I was aware in the 1970s of Martin Iorns and Fibersteel, and the radical technique they developed, through an American engineer friend of mine.

    A brief history: Our first boat was a 55 ft motor-sailor called a Valeo. We just built the hull, deck and bulkheads. The customer took it from there. The parent company had already built a Valeo in a floating mold.

    We built a female mold with steel mesh on plywood mold frames using a proprietary mixture including Portland cement, sand, vermiculite, and, an acrylic latex called Experimental Emulsion E330. I was told it was basically the liquid portion of acrylic latex paint, without the pigment. Supplier: Rohm and Hass. The vermiculite was used to keep it light.

    The process: First we sprayed a release agent onto the mold. Then, we sprayed a proprietary mixture of Portland cement, pozzolana and E330. This was the functional equivalent of Gelcoat in fiberglass boats. It was dense and waterproof. After setting, starting at the keel, this was wetted with E330 and a coat of cement consisting of sand, pozzolana, Portland cement and a wetting agent to assist pumping, was sprayed onto the hull. (Another proprietary recipe) Into this layer, we rolled a sheet of expanded metal, pressing it down with rollers. The same method as used in fiberglass layup. More cement mix. Next, we laid another sheet on top of the first, overlapping as you would shingles. And so on, up to the deck edge. In two days we laid up a 55’ hull. A plastic tent was draped over the hull and steam pumped in for a faster cure.

    Pozzolana is a volcanic ash. it was used extensively by the Romans in their concrete.

    The deck/deckhouse was laid up the same way. Bulkheads were laid up on a horizontal surface.

    We next built six 34’hulls of a design called Saugeen Witch,  by Tom Colvin.

    Shortly after that, we went into receivership because of lack of cash flow. We weren’t selling our product fast enough.

    There were many life lessons in that experience. As I said, I could write a book.  Was mich nicht umbringt, macht mich staerker. -- Nietzsche
    Last modified: 06 Apr 2020 16:39 | Anonymous member
  • 01 Apr 2020 22:09
    Reply # 8873098 on 8866120

    That's very interesting Jim. I was aware in the 1970s of Martin Iorns and Fibersteel, and the radical technique they developed, through an American engineer friend of mine.

    When you get time I would enjoy hearing from you on this, either on this forum or by email.

    By the way Jim, when you were in NZ I promised to try and find you a copy of The Southseaman by Weston Martyr. I managed to lay my hands on one. When all this is over, I'll post it to you if you want. You will enjoy it.

    Last modified: 01 Apr 2020 22:09 | Anonymous member
  • 01 Apr 2020 20:19
    Reply # 8872780 on 8866464
     The obvious way is to do a gunnite layup inside a female mould and lay the fibres into the cement, rather than plastering over a mesh matrix. Fibersteel in the US built at least one ferrocement boat in this way. This would not suit amateur one-off construction. I’m like you, too little time left now for too much more of this sort of fooling around. Also, you are right – ferrocement is no longer a cheap way of building (if it ever really was, since, as you say, most of the cost is not in the hull anyway.)

    In 1972 I got involved with a group that set up a company called Atlantic Fibersteel Marine, in Mahone Bay, NS, Canada. We bought a license to use the Fibersteel method developed by Martin Irons. Martin came up from the US to help us with our setup. 

    Stay tuned, I'll come back later to finish this story.

    I aged/matured 5 years in one. I should have written a book...

  • 01 Apr 2020 01:34
    Reply # 8871196 on 8866120

    I'm going to get conversational and ramble here, no apologies. These are difficult times and this is as good an alternative as any to "whistling loudly" in order to reduce anxiety and induce thinking about other things.

    Arne - interesting photos. There are plenty of ways to skin a cat and I have no doubt the boats you refer to were sound and good. Richard Hartley was adamant in the use of truss frames and advocated not using transverse rods in the armature of all his smaller boats, including the South Seas. I guess the one in your photo was either not a Hartley, or it was a larger vessel as I can see the transverse rods (on a 45 degree angle). Personally I followed Brian Donovan's school of thought which was placement of longitudinal rods along the diagonals, transverse rods on an angle, structural floors and structural sole, and building over wooden temporary mould frames. In his writings and in his lectures, Hartley was totally one-eyed about his construction design and methods, which were based on his past experience as a wooden boat builder.

    (As a digression I once heard him justify his permanent truss frames by analogy with a canvas-covered canoe, and the fact that it would collapse if you took out the frames! He was not an engineer and he seemed to have a hatred of engineers, especially academics. I have seen him engage with Morley Sutherland (an engineer ferrocement pioneer) about these matters and feathers were very ruffled on both sides. That said, his designs worked reliably all around the world. A little-known fact is that, including his catalogues, he was in his day New Zealand's best-selling author.)

    And he was adamant about using the 2-shot method. Yet to talk to Richard personally on a one-to-one basis he was a really nice guy, kind, helpful and always willing to discuss. None of his ferrocement designs had any visual beauty in my view - except perhaps the RORC series, to a degree - but I commercially fished for 10 years out of a modified Hartley South Seas and got to like it. (We took a sledge hammer to it, chopped a metre off the stern, smashed off that ugly semi-clipper bow then repaired the damage. We shortened her down to 35' to avoid the survey regulations, and she was a better boat for it. It served me well and paid for itself many times over. The old transom (which must have weighed half a ton) is still lying in the mud down here in the mangroves. I will put photos and all that story up on my website later when I get time.)

    The Lone Gull turned out to be a superb longliner, I wouldn't have changed a thing more. The black longliner, Heidi Lisa, on the left, in the fishing basin photo,  is a Hartley Coastal 32. (Man, could that thing stand on its stern and pitch, when bucking a head sea. Did a lot of miles and caught a lot of fish though).

    Paul, thanks so much for those brilliant links. I am absolutely gutted now that I have gone too far in meshing up my current project with steel mesh, and commenced the plastering. I would rip it all off and use basalt fibre but there are about 7,000 or 8,000 staples holding the mesh down! (I used a battery-powered staple gun, burned out the first one, dropped the second one in the tide and I'm on my third. Brilliant device.)

    One of the links Paul gave me shows basalt rod, it appears to have better (memory) characteristics than semi-high tensile steel for using in a conventional ferrocement-type armature layup. Two directionally opposed layers should fair themselves up nicely.

    I would say a one-off BFRC hull along conventional FC lines would be feasible, and also being potentially stronger/stiffer it might be possible to move away from the double-compound curvature and look at hard chine models.

    Female moulds, gell coats and mortar with chopped strands sprayed onto a layer of mesh would probably be the shot for commercial production.

    I've got 45-year old tested ferrocement sheathing specimens here and I'm going down that road personally, for this somewhat extreme hull design. I have done it on a round bilge launch, but although the sheathing was satisfactory the result was not, so I don't recommend it generally, unless sheathing an old worn-out hull that would have to be scuttled otherwise, in which case it can sometimes be "just what the doctor ordered", depending on hull shape, displacement etc.

    Basalt fibre would have been lighter, stronger, and a cinch to apply as a sheath - and I would have considered stopping the the sheath at the boot top. Food for thought. Too late for me now.

    Marcus reckons he will pick up the baton. Some day.

    Last modified: 01 Apr 2020 06:27 | Anonymous member
  • 31 Mar 2020 14:42
    Reply # 8869594 on 8866120
    Anonymous member (Administrator)

    Here are two photos from the plastering of a Hartley boat (South Seas?), in 1976.

    One photo shows the process of pushing all the cement through from the inside, with a controller on the outside.

    The other shows how the owner is floating off the half-set cement with a ‘board’ of Styrofoam. This worked well, and the boat came out very fair.


  • 31 Mar 2020 12:59
    Reply # 8869434 on 8866120

    Graeme, this is a fascinating topic and I hope you continue to update us on this. I've been following this basalt and concrete thing for a long time and I was sure somebody would revisit the ferrocement building method but using basalt instead of 'ferro' rebar. Oddly, nobody seems to have done this until you so at long last we might get some empirical evidence as to the suitability of basalt instead of people just reposting articles from materials engineering websites.

    I cannot give you any hard won knowledge from hands on experience as I found information on standard ferrocement scarce enough but I have a feeling that instead of following the ferrocement methods, the new way would be likely influenced by progress made in the field of glass fibre reinforced concrete (GFRC) which has advanced hugely in the past 10 years alone. 

    Useful links are:

    A useful primer on youtube for GFRC in general:

    Any youtube videos by TrinicLLC are very useful:

    Incidently, a Danish chap by the name of Ole Brandt started a GFRC company off the back of the research he made in building ferro-free cement boats. As I understand he made one many years ago under the name of Elvira. The company he started is called BBFiberton

    Hope some of this is of use in your project

  • 31 Mar 2020 11:48
    Reply # 8869339 on 8866120

    Thanks for the reference Arne, I just love those old JRA magazines. The ferrocement pair trawlers look very odd for ferrocement, with those high unsupported bulkheads and flat sections. They don't seem to be floating too low in the water though. They appear to have water-pipe rail caps.

    Bulwarks are best not made in ferro. And double compound curves suit the material best.

    You may be right about the fibreglass being polyester not epoxy.

    "Floating off" with styrofoam boards eh? We learn something new every day!

    David, thanks for the technical information. The claims I read on the internet about basalt  being as strong as carbon fibre appear to be an exaggeration. Yes I think the fibres must suit high temperature applications well. Years ago I had an ambition to make a stove from ferrocement, and researching recently for a way to make castings for Marcus's woodstove on Havoc is what led me to the basalt fibres. I just made a grate for Havoc's stove, from basalt fibre reinforced refractory cement, and I am rather chuffed with the result.

    Can't wait to fire it up and see what happens.

    Last modified: 31 Mar 2020 12:14 | Anonymous member
  • 31 Mar 2020 10:26
    Reply # 8869301 on 8866120
    Anonymous member (Administrator)


    in my area of Norway, at least,  ferrocement boatbuilding was strictly  for amateurs, so only the one-shot method of plastering was used. Still  the method of pushing all the cement through from one side appears to have produced good hulls  -  but it surely was hard work. When the cement had started to set, one went over the area with long boards of quite hard Styrofoam.

    You mention that glass sheathing may come unstuck. Could it be that polyester resin had been used instead of epoxy? Polyester resin and cement are not good friends.

    As for ferro junks in China, they are briefly mentioned in JRA NL 28.

    I still have a soft spot for ferrocement. The way that big Colin Archer, with all its double compound curves could be built, more or less by ‘knitting’ small pieces together, was pretty amazing. Very simple tools were needed.


  • 31 Mar 2020 08:30
    Reply # 8869139 on 8866120

    When I have been buying carbon and Kevlar from Soller Composites, I have noticed basalt among their offerings,  and it still seems to be there, but only as unidirectional tape. They do still have a chart of relative strength, stiffness and temperature resistance, which puts basalt on a par with S glass and better than E glass.

    Its chief advantage seems to be for high temperature and fire resistant uses, eg:

    It seems to be used for laminates that are stronger and stiffer than GRP but cost less than CFRP. I can't see any other valid reasons to use it for boatbuilding, and certainly not for spars as its strength/weight and stiffness/weight ratios are not as good as for CFRP. The one exception is replacing steel in ferrocement:

    "Sudaglass (Houston, Texas) produces several products from basalt fiber, including concrete reinforcement rods. Pultruded from unidirectional basalt fiber, the rods are reportedly 89 percent lighter than steel reinforcement rods, have the same coefficient of thermal expansion as concrete and are less susceptible to degradation in an alkaline environment. The company claims that that 1 ton of basalt rods can provide reinforcement equal to 4 tons of steel rods."

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  • 31 Mar 2020 00:48
    Reply # 8868694 on 8866120

    "I guess basalt fibres might be more suited to production boat-building".

    You are probably right at the moment, Graham, but there are many ways to skin a cat and I would not preclude the possibility of a DIY-suitable technique evolving.

    Also, I have not yet been able to get my hands on some basalt reinforcing rod.

    Cement seems to be a thing of the past for most people now, anyway. Basalt fibre reinforced resin might be more promising. I'd like to see a spar made of it. I wonder what David Weaverbird  thinks if it?

    Arne's photo gave me a moment of nostalgia too. Back in the day, back yards with projects like this were to be seen all over NZ.

    I hope you get a chance to try out your lovely new sail quite soon.

    Last modified: 31 Mar 2020 01:02 | Anonymous member
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