We love Ferro cement but beware !

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

  1. hoytedow
    Joined: Sep 2009
    Posts: 5,784
    Likes: 359, Points: 93, Legacy Rep: 2489
    Location: The Land of Lost Content

    hoytedow Fly on the Wall - Miss ddt yet?

    ...or the matching ferro anchor chain.
     
  2. troy2000
    Joined: Nov 2009
    Posts: 1,743
    Likes: 170, Points: 63, Legacy Rep: 2078
    Location: California

    troy2000 Senior Member

    That's what I meant to type: the ferro chain rode for the anchor....it's a booger, bending up the rebar for all those links and then plastering them.
     
  3. hoytedow
    Joined: Sep 2009
    Posts: 5,784
    Likes: 359, Points: 93, Legacy Rep: 2489
    Location: The Land of Lost Content

    hoytedow Fly on the Wall - Miss ddt yet?

    The windlass would also be a booger to do.
     
  4. ancient kayaker
    Joined: Aug 2006
    Posts: 3,497
    Likes: 147, Points: 0, Legacy Rep: 2291
    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    I keep getting this mental image of Brent out in the rain welding up a steel hull and singing
    "I'm welding in the rain, just welding in the rain, what a glorious feeling, Oh! I got zapped again ..."
     
  5. dskira

    dskira Previous Member

    This one is so funny, I still laughing my *** off while trying to post.
    I see the image in my head, like a cartoon.
     
  6. gonzo
    Joined: Aug 2002
    Posts: 15,254
    Likes: 952, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    But look at the upside. It is only two days of welding in the rain
     
  7. Brent Swain
    Joined: Mar 2002
    Posts: 951
    Likes: 35, Points: 0, Legacy Rep: -12
    Location: British Columbia

    Brent Swain Member

    You are right. Wood is a great material for a boat that spends little time in the water. That is one way to reduce maintenance on a wooden boat.
    Building in rainy BC, I prefer the winter, as it lets one wear better protective clothing. Summer, you can fry eggs on plates out in the sun. You make far more progress per hour in winter on a steel boat. I have only been held up a couple of days in a couple of weeks in BC waiting for the rain to stop. With building a hull in two days ,it involves some strenuous gmnastics, and by the time the rain begins again , you are overdue for a break. When it stays clear for too long , you tend to burn yourself out trying to make the best of the weather.
    For summer working, I once insisted that an owner ,who's bare steel boat had deteriorated to the point of needing sanblasting , give her a coat of free white paint from the recycling centre, before I worked on it. He did and it was cool to the touch, like air conditioning inside.On the grey primed one next to it, it was hot enough to fry eggs on. I'm now looking for a white epoxy compatible primer for such jobs.
    On one 36 I built, the owner had the use of a plasma cutter and knew how to use it well. I had the torch. The steel came thursday afternoon , and by 11 pm the following day we had the hull pulled together the longitudinals in , transom in, and the bullwark caps on.
    I've pulled together a 36 ft hull , decks, cabin, cockpit, keel, skeg and wheelhouse in six days, working with an owner who knew a bit about steel working. Sure, an amateur woud take possibly twice that long, possibly more, but far less time than building in wood or any other material.
    I used to have to work with the owners, but with my book, plans and Alex's DVD many more owners are building their own boats, with no problems.
    It takes a minute or two, and under two dollar's worth of material to build and weld down a stainless cleat, which would cost the average wood or fibreglass builder $40 and an half hours work to do. Ditto most detail.
    I've had several friends, meticulous woodworkers , who soaked their wooden boats in the most modern epoxies. They are all leaking and showing dry rot by now. Several , former wood boat fanatics, have sold their boats and bought fibreglass boats.
    Rust happens out on the surface , where you can see it and deal with it. Rot happens deep inside ,where you remain unaware of it's existence , until it becomes a major problem. 60 hours to repair dammage from a dragging anchor? One of my 36 footers pounded for 16 days in 8 ft surf on the west coast of Baja. They dragged it off thru 8 ft surf, being dropped repeatedly 8 ft, every wave on hard packed sand for 1/4 mile. They then sailed it back to BC, no repairs but tightening the rigging. How much repair would a wooden boat take in the same situation?
    Ferro cement. A far better and more maintenance free boat than wood, no rot , no teredos, doesn't burn, a bit heavy, but what boat well fitted out and lived aboard full time over several years is light? None. They can be bought so cheaply that after a year or so living aboard they are virtually freebies, compared to the cost of living without one. Then if you lose it on a reef , you are still money ahead. You may even be able to salvage enough stuff to outfit your next boat , a steel one. Been there, done that.
     
  8. Tad
    Joined: Mar 2002
    Posts: 2,307
    Likes: 191, Points: 73, Legacy Rep: 2281
    Location: Flattop Islands

    Tad Boat Designer

    I'll take that for the entire thread.......

    Sometimes I wonder at the point of these endless circular arguments?
     
    1 person likes this.
  9. troy2000
    Joined: Nov 2009
    Posts: 1,743
    Likes: 170, Points: 63, Legacy Rep: 2078
    Location: California

    troy2000 Senior Member

    You're on a roll, aren't you? You aren't going to let a little thing like facts get in the way of your missionary fervor.....

    I'm pretty much done; there's no sense in encouraging you. But I'll pass along an anecdote about what can happen to steel, to show that it isn't an impervious, indestructible building material. The story is part of a long, reasoned post by a gentleman on another forum, who isn't impressed with steel as a boatbuilding material:

    Then there is electrolysis. This used to be the kind of problem that was a compelling reason not to own a steel boat. In the early 1970’s I worked in a boat yard that had to do an emergency hauling of a steel power boat to prevent it from sinking. This boat which had been launched weeks earlier in perfect shape had changed slips and was tied up next to a boat with an improperly grounded 110 electrical system and in a mater of days the bottom of the power boat in question had lost sufficient thickness and was covered with small pin holes that the boat needed replacement of her entire bottom plating. This kind of loss was not covered by insurance. Today, there are ways to combat the electrolysis problem but, in my mind, they are bandaids treating symptoms rather than real cures to the problem.

    http://www.sailnet.com/forums/sailboat-design-construction/39728-steel-hull-construction-2.html
     
  10. MikeJohns
    Joined: Aug 2004
    Posts: 3,192
    Likes: 208, Points: 63, Legacy Rep: 2054
    Location: Australia

    MikeJohns Senior Member

    Troy
    Query what you read on forums :mad:

    That post contains dis-information from someone who is really just embellishing a very biased view with a very tall sory.

    The same poster said this a couple of posts later:

    "Corrosion moves at a constant rate of speed, so when you look at a big ship which may be plated with 1 1/2 to 2" plating, loosing an 1/8" of steel in a couple decades is no big thing"

    This is a nonsense, (both the thickness and the corrosion rate) whether a steel vessel corrodes depends on its build and and the maintenance of its coatings. Too many designers and builders simply do a very poor job with steel. Consider that there are very well built very old steel vessels who's hulls are largley original.

    As for the perfect steel hull that supposedly started sinking weeks after launching and days after encountering a hot berth this is also a nonsense.

    Electrolysis damage is easy to spot, firstly the low resistance bonded bare metals get eaten that is the anodes then their plates and studs, and at the same time any other bonded bare metals, usually the prop and the shaft and often the lower rudder shaft.

    The painted hull plate would only be breached over many months. The pits seldom breach the hull and are clearly visible, localized and are usually a bright shiny area about the size of your palm. The energy available to errode the cathode depends on the current and surface area, sea water has quite high resistance and the electric field follows the usual field physics with high field concentrations around already exposed metals. This is why the areas of depletion remain as a very limited number of localized and well defined patches.

    In reality in a hot berth at an annual haulout you'd find all the anodes heavily depleted and the prop tips eaten and maybe a few shiny partially depleted patches on the hull plate.

    One photograph would prove the point.
     
  11. troy2000
    Joined: Nov 2009
    Posts: 1,743
    Likes: 170, Points: 63, Legacy Rep: 2078
    Location: California

    troy2000 Senior Member

    I suppose it might be nonsense, although the poster has been around sail.net since 2000, and is a moderator there.

    It can't possibly be more nonsensical than Brent's hysterical claims about wood, including his assertion that a wooden boat starts costing thousands of dollars in maintenance annually as soon as it's launched.
     
  12. Brent Swain
    Joined: Mar 2002
    Posts: 951
    Likes: 35, Points: 0, Legacy Rep: -12
    Location: British Columbia

    Brent Swain Member

    My last boat, when it was surveyed, had bare steel on the bottom of her keel which was as good as the day I welded it on , after 9 years of cruising . It had never been painted. Other bare spots were just as shiny. The surveyor said it was becasue she had never been moored at docks with 110 volt ac power.
    I guess that elecrolysis is what we are paying for when we tie to docks. I spend my moorage money on cruising full time , which costs far less than moorage. Isn't that what cruising boats are for?
    My current boat is 25 years old, and the bottom of the keels have rarely had paint on them, and then only briefly, yet look like freshly sandblasted steel. Steel doesn't corrode without a reason . It is simple to find the reason and eliminate it.
     
  13. ancient kayaker
    Joined: Aug 2006
    Posts: 3,497
    Likes: 147, Points: 0, Legacy Rep: 2291
    Location: Alliston, Ontario, Canada

    ancient kayaker aka Terry Haines

    Did the cement wear off?
     
  14. Landlubber
    Joined: Jun 2007
    Posts: 2,640
    Likes: 124, Points: 0, Legacy Rep: 1802
    Location: Brisbane

    Landlubber Senior Member

    "I suppose it might be nonsense, although the poster has been around sail.net since 2000, and is a moderator there.

    It can't possibly be more nonsensical than Brent's hysterical claims about wood, including his assertion that a wooden boat starts costing thousands of dollars in maintenance annually as soon as it's launched."


    .......and this gives the poster cred.........I think NOT.


    the sky is falling, I'm off to tell the King...
     

  15. Landlubber
    Joined: Jun 2007
    Posts: 2,640
    Likes: 124, Points: 0, Legacy Rep: 1802
    Location: Brisbane

    Landlubber Senior Member

    I bought a Tramp Steamer in 1981, she was 160 feet long, built in Germany 1957, manufactured spec was 13mm, tested......guess what.....13mm

    Riveted construction, worked her guts out the poor girl, but she was as good as new in many places.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.