Ferrocement to strengthen / waterproof inside of steel hull

Discussion in 'Boat Design' started by Beginner123, Jul 16, 2013.

  1. Beginner123
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    Beginner123 Junior Member

    James Craig

    Looked it up and it's a nice ship.

    Must have taken thousands of hours and hundreds of thousand dollars to repair it.

    Wonder though how much of the original ship is still left though. The framework inside?

    I can't help but wonder if a similar method of cement / plastering would work with the boat I'm looking at or if it's just too temporary.
     
  2. hambamble
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    hambamble Junior Member

    Mike and Jeff, Thanks for the replies. It's pretty interesting how they did it!

    Beginner, I think its worth saying a few things,

    1: Surveys cost money for a reason. So many boats appear to have one problem, but instead have many. Rust is a big deal, it usually means that the hull has been poorly maintained, and a poorly maintained hull, usually means poorly maintained engines, electrics, tanks, etc.

    2: I know how tempting it is to buy a bit of a wreck because it seems cheaper, particularly having just done it with a sailing dinghy. But I went for a smaller boat that i could afford repairs on, I could afford parts for, and if something big broke I could afford to fix it. I know someone who recently got the mechanic out because the starboard engine on their 36 footer was burning about 20% more than the port engine. About $15,000 later, the problem is fixed. It was a dodgy waterlock, which allowed salt water back through the engine, and corroded the aft valve so badly that it wouldn't hold a seal. This boat was in fantastic condition too, the sort of varnish jobs on the timber work you could see yourself in. You need to have some spare cash in these situations.

    3: Boats should be fun. This one will be a headache, both on you and your wallet. If your on a limited budget, I suggest getting something a bit smaller, that might be cosmetically run down, but structurally and mechanically sound.

    4: Cheap boats are cheap for a reason

    That being said, if you have your heart set on it, go for it. Just don't kid yourself about the time and expense it will require
     
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  3. waikikin
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    waikikin Senior Member

    Hi, these kind of restorations are measured in man-years, in the case of "James Craig" around 21 million$ in yesterdays terms, & not including the value of Volunteer labour that was invested in the restoration... maybe 40-50 million now, ongoing maintenance is by Volunteers with professional guidance.
    As Hamble Bamble has indicated, the cheap boats dont end up cheap, the "free" ones probably cost even more, just as an example you could compare a popular small yacht such as a J24........ if you buy one that's been maintained/ raced/been "dry sailed" for 15-20 thousand & go sailing tomorrow, compared to buying a $3-4000 thrasher that was on a wet mooring, needed slipping,some osmosis blisters fixed, antifouling, new ropes, new standing rigging, couple or mouldy sails replaced, broken tiller, one missing winch, repaint on the topsides & freshen up the slip resistant coating,............. & enjoy sailing it in 6months-2 years + costs later, if you like fixing things that's great.
    Al the best from Jeff
     
  4. Beginner123
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    Beginner123 Junior Member

    Decided

    Hi everyone,

    I've received many warnings here about the amount of work and money it will take to repair a wreck so I've decided I won't buy it unless by some miracle the hull is still in a pretty great condition with some rust on top. I'll take an ultrasonic thickness gauge with me (if I can get one and if it works when the hull is floating on water) and take 3 measurements every metre or so.

    In the unlikely case that it somehow works out I'll have a new look at whether applying new steel plates or ferrocementing will work the best. I still like the idea of ferrocementing (I guess because of the smaller costs: Portland cement and silica sands are affordable and chickenwire can be acquired secondhand from some person who isn't using it. It also seems easier to carry out.)


    Anyone got an idea what a reasonable thickness would be for the hull to be strong and leakage-free?

    Thanks for all your comments and helpful advice. It's good to have some level-headed feedback when you've got this dream inside your head.

    @Hambamble
    Amazing how something seemingly like that could cost 15,000 euros.
    I'll keep the headache part in mind. ;)

    @Jeff
    Woah, $21 million. I think I'm getting your point.
    I have a lot of respect for the people who took this on. In the pics I saw it looked like they almost took it apart and then put it back together again / restored it.

    I must mention the boat I was considering buying costs around two hundred euros.
    This should explain at once both how lucrative it will appear (not just in terms of cash but just the idea of having your own house boat at this age) and how bad its state could be.

    I'll let everyone know once I've been able to get some testing done. :)
     
  5. messabout
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    messabout Senior Member

    The upside of a ferro lining is that it would dampen some of the noise and provide a little better thermal insulation than cold steel. If nicely finished it could even improve the cosmetics.

    The weight can be consideable though. A rum influenced SWAG is that a 2 inch veneer could add several thousand kilograms and result in a sinkage of 30 centimeters or more . That's with the wild guess of 40 foot LOA and 12 foot beam. Whether that matters depends on the depth of the water where it might matter. For sure it'll be harder to get it moving and harder to stop once underway.
     
  6. Beginner123
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    Beginner123 Junior Member

    Advantages & disadvantages ferrocement

    @messabout
    I hadn't considered thermal and sound insulation. Good point.

    Thermal insulation would especially helpful because of the costs of heating the vessel with natural gas or diesel in the winter in the Netherlands (~200 euro per month from what I have read, guess it depends on what cabins you use). Adding some more actual insulation would, I think, also give a good return on investment.

    Extra weight is less of an issue to me because I don't intend to travel a lot after it's reached its decision. The intention is to just live in it and seldom move to a new mooring spot. I don't know what the ramifications of the extra weight could be on the load on the steel and complicated physics like that that (I mean we're talking about a hundred-years-old rivets here). How low the centre of gravity is won't change much and might even improve slightly.

    I can understand maneuvrability would be greatly decreased. The (small) upside is that the boat should be more stable, I think.

    I want to strike a balance in weight and the strength of the ferrocement. That's why I wonder about the number of layers of chicken wire / thickness of cement to use.
     
  7. Beginner123
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    Beginner123 Junior Member

    Rum-influenced sw...you mean you wrote that post with a bottle of rum on the side? :)
     
  8. Beginner123
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    Beginner123 Junior Member

    Just kidding.
     
  9. Beginner123
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    Beginner123 Junior Member

  10. rasorinc
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    rasorinc Senior Member

    Your dealing with over 100 + year old steel and have no idea how it was made or the standards it was made to. I would not touch this boat even if it was delivered to my home and was free. You are considering buying an unknown mystery and you will not be happy with the outcome. Walk away and continue your search. That is the best advise I can offer you.
     
  11. Beginner123
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    Beginner123 Junior Member

    Ah, greatness. Just found out from forum link below that it is possible to do ultrasonic thickness testing when the hull is submerged in water.
    The person mentions that it is harder to access but this is less of an issue given 50 cm gap between wooden construction and bottom of hull.

    Another quote from forum:
    "A very simple starting point !! If you can dive on the boat and check the Anodes if they are gone ( eaten away to nothing left ) I suggest that you be gone !!! There is every chance that you will have major repairs to do also if there is rust around the water line this is an area that will show that there is no anode protection so head for home and find another boat to look at Cheers Jacko"

    It hurts...

    http://www.cruisersforum.com/forums/f55/testing-a-steel-hull-for-defects-64884.html
     
  12. Beginner123
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    Beginner123 Junior Member

    Now only question left is if the ultrasonic thickness gauge will measure properly through the rust.
     
  13. Beginner123
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    Beginner123 Junior Member

    Actually from what I'm reading now thickness testing may be quite difficult, needs to be calibrated for paint, etc. Seems to be an art on its own.
     
  14. Beginner123
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    Beginner123 Junior Member


  15. Beginner123
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    Beginner123 Junior Member

    @Rasorinc

    Advice noted.
     
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