We love Ferro cement but beware !

Discussion in 'Boat Design' started by manta.bay, Feb 23, 2008.

  1. capt littlelegs
    Joined: Apr 2010
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    capt littlelegs New Member

    The problem that I've found with fiberglass mass production is that too often they are built down to a price and are too thin, because they can be built like an egg shell! In a fibreglass boat you will often hear all the water noises which is not encouraging! You don't hear any of this with a ferro hull and I know who would win in a ramming contest! I don't mind if others don't like ferro as it keeps the price down, I bought mine for half the cost of a fibreglass boat and it's better equipped so I don't have as much money floating about. The information is that ferro gets stronger with age, you can't say that about other materials, even steel will rust eventually but as with anything there are many bad ones out there and I'd be very choosy.
  2. Brent Swain
    Joined: Mar 2002
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    Brent Swain Member

    This is a good reason to avoid newer fibreglass boats , but seek out a pre 1980 hull, from back when materials and labour were cheap, ossmossis unheard of, and when no one quite trusted it structurally.
  3. tugboat

    tugboat Previous Member

    Terry- its just a thought but wouldnt ferro cement used as a core beneath say epoxy and fiberglass mat in three layers per side, stop the a ferro hulll from any cracks and resist impact damage? the cost of standard core material for a large boat is enormous but if one could use ferro cement as a core and epoxy the hull inside and out using glass--wouldnt that be a unbelieveably strong and impact resistant hull? that would make a fc composite hull even though fc is already a composite...??..its justa thought...
  4. DrCraze
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    DrCraze Junior Member

    The last thing you want to do is laminate a layer of fiberglass to the hull. Ideally you want to keep the cement serviceable. If you catch a spot of rust simply divot the spot and fill with non sanded grout mixed with acrylic.

    I think the common misconception between ferro-cement and a typical concrete structure is that they have anything in common. In fact proper ferro panel is very crack resistant and behaves much like a fiberglass composite. More fiberglass would be redundant.

    The most surprising thing I have observed during my limited experience with a ferro boat is the incredible flexibility of the hull after it has been pulled from the mold.
  5. tugboat

    tugboat Previous Member

    Capt littlelegs- That's what I think too- ferro went in the wrong direction when they replaced mesh with chicken wire- people used it because the impact damage was supposed to spread out more absorbing the impact and the layers of mesh de-laminated when overloaded- and the chicken wire could be made to form better over compound curvature- so chicken wire was more of an adaptation to fit the builders ease and not the design need to fit the material.

    the strength of FC with mesh is far superior to my knowledge.

    If i do build a ferro boat in the future it wont be with chicken wire...Benford talks about this somewhere i was reading. He states emphatically not to use chicken wire- and i have to agree- because with mesh you have a much stiffer structure. As well the material tends to "bounce" back into place instead of just fracturing. the bad points are the layer/sandwich type of de-lam effect of the material when impacted. But to me that's not a big deal you simply re plaster later.

    to be objective- i searched the Benford site for any tugboats designed for FC- alas there were none...

    Rwatson--I have to submit to your points on high cost and strength of fiberglass...shear strength yes- and ductile strength...perhaps.
    But i don't know if I agree that it has the same impact resistance of ferro for sharper objects? to have the same it would sure have to be thick fiberglass...not cored either. fiberglass sure is easy to use--but certain types of light make the material brittle. and nowadays most people are using core for stiffness-0- and believe me-its expensive for good core material. and then there are probs with de-laminations as well and osmosis..I don't like vinylester and if your going to build a fiberglass hull- go all the way and use epoxy.
  6. WestVanHan
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    WestVanHan Not a Senior Member

  7. DrCraze
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    DrCraze Junior Member

    Shhhhh...your blowing preconceived notions out of the water:p
  8. tugboat

    tugboat Previous Member

    LyndonJ- sorry it took so long- i got cought upin some other forums- i apologize i dont ahve any pics-i havent looked yet and i have been busy- i will get to it...if i cant find any--ill have to concede your are correct.

    btw i will be building in steel...

    here is a quote from my thread --its self-explanatory...i hope the poster does not mind me using it...
    the thread has to do with decreasing plate thickness to save a little on plate costs. i took his advice btw.

    "To the original poster:

    I personally wouldn't go any thinner than 1/4" .... I design tugs and OSV's for a living and trust me you can't put too much steel into a workboat. I have seen owners punch a hole in a 1-1/8" shear strake. 1/4" plating doesn't give much room for wasting and after a few years a sand blaster will punch holes through your hull."
    Its all i have for now LynbdonJ...
  9. BillAU
    Joined: Jun 2010
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    BillAU Junior Member

    Ferro Cement Boats

    For those of you seeking helpful advice on Ferro Cement boats...From people who own and sail them, check-out this URL The page contains a bunch of links to Ferro Cement boats, their owners and where they are sailing. There's also a link on there to a site that promotes...American building and racing of concrete canoes!
    Who said "you can't build a small boat using Ferro Cement"? Someone must have forgotten to tell the "American builders and racing concrete canoe" mob :)
  10. tunnels

    tunnels Previous Member

    Yeah yeah !! My father Knew Everet Sayer and his brother Ron Sayer both plasters in there own right and both there familys , I sailed with the Sayers in the 60s a few times and went away for long weekend to places off the nz coast .I was in my teens then but remember it will and have lots a photos of there Yacht that my father had fitted a Yanmar motor to in Whangamata .
    Ron had a big power boat with a ford 6 motor that he bought from the ford garage where i worked !! " SEA JAE" was the name if his boat!
    Ah those were the days !!!:D
  11. BillAU
    Joined: Jun 2010
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    BillAU Junior Member

    (Originally Posted by lazeyjack
    when i was up in Fiji in early 80 I saw and met folks in ferro who were too scared to move)

    Lazyjack! You don't know Kiwi's...They were too scared to move...Off their bar stools, because they were so pi-eyed they didn't want to fall down ;)
    As for Kiwi's and Ferro boats...Kiwi's love Ferro boats, have you not read about Hartley Boats? They've been around for 70 plus years and the Kiwi's build and sail some beaut Ferro yachts :D Just try to get a Kiwi to sell his Ferro boat on the cheap...He/she will soon tell you what you can do with your offer!
    A quote from Hartley Boats

    Hartley & Brookes boat plans is the oldest business of it's kind. Since the first plans were sold for home construction in 1938, it is estimated that in excess of 95,000 Hartley Boats have been built. Apart from 'class dinghys', there are probably more Hartley Boats throughout the world than any other designer. And probably more Hartley ferro-cement boats than all other ferroboat designers added together. Read more.
    End Quote.

    A Ferro Hartley, around 38', pro built in NZ, (or built to spec's wherever) would suit me just fine :D
  12. Capt JZ
    Joined: Dec 2009
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    Capt JZ Capt JZ

    I was once told by a very experienced seaman..."People who sail concrete boats should drive concrete cars !"
  13. tunnels

    tunnels Previous Member

    Yeah with all the dumb *** idiots on the road i wish i did !!:mad:
  14. MikeJohns
    Joined: Aug 2004
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    MikeJohns Senior Member

    I had a Fijian for 3 or 4 years. Stem on they are strong in collision but beam on they are very weak. I sold that one on but the boat is now sunk, it was washed against a rock shelf and went down very quickly. It's free for the salvage. I think every Ferro boat I know that was washed onto rocks and survived ended up with significant problems later on due to often undetected cracking. Marina hardstands used to be littered with them. There was one in Gladstone had a tree growing out of it when I was last there a few years ago!

  15. wardd
    Joined: Apr 2009
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    wardd Senior Member

    ferro cement derelicts last forever
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