Philippines Traditional Boat Update

Discussion in 'Boat Design' started by CaramoanReef, Feb 16, 2023.

  1. CaramoanReef
    Joined: Jul 2016
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    Location: Caramoan, Camarines Sur, Philippines

    CaramoanReef Junior Member

    I'm in a remote location, so the materials available are limited. I'd appreciate some advice!
    I have a 30' traditional style "bangka" boat made of wood. The bottom of the boat is a solid piece of wood they call the "kasko". The sides are plywood. There is a kind of worm that gets into the wooden hull and burrows through the wood making big holes. The boat is much heavier than when I first got it due to all the water filling these holes.
    My goal is to fill the holes in the bottom part of the hull with PU foam. Then put a layup of polyester resin on the outside and inside to stop this from happening again. I was planning to layup 1 layer of mat, 1 layer of roving, and 1 last layer of mat.
    I know there are issues with getting polyester resin to stick to wood. Epoxy would be better. Unfortunately, epoxy is not available or is prohibitively expensive to buy here.
    Any advice to make this work? I will post some pictures...
    Thanks!
     
  2. Waterwitch
    Joined: Oct 2012
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    Waterwitch Senior Member

    What people do is drive a series of tacks to hold your roving layer on mechanically, then cover the fastener heads with your layer of matt. Videos I see of Vietnamese wooden fishing boat building, they seem to use multiple layers of matt and no roving to make their glass skins.
     
  3. CaramoanReef
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    Location: Caramoan, Camarines Sur, Philippines

    CaramoanReef Junior Member

    Thanks for that info. Do you know what kind of "tacks" they use? Like a stainless steel nail? Will the tacks show through and make the final design bumpy? Thanks!
     
  4. bajansailor
    Joined: Oct 2007
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    bajansailor Marine Surveyor

    I had to google bangka boats -
    Bangka (boat) - Wikipedia https://en.wikipedia.org/wiki/Bangka_(boat)
    Does your boat have sails or just a motor?
    What do you use her for? Can you post a photo or two of her please?

    Even though epoxy is prohibitively expensive, would it be possible to order some in from the place that supplies the polyester resin?
    If so, then you could perhaps sheath the hull with just a thin glass cloth - all it has to do is to keep the worms out.
    If you sheath it with a combination of CSR / WR / CSM you will use a lot more polyester resin, and the cost difference will be a lot less at the end of the day when the job is finished.
    You would have to ensure though that the hull is reasonably dry before sheathing it with any material.
     
  5. CaramoanReef
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    Location: Caramoan, Camarines Sur, Philippines

    CaramoanReef Junior Member

    Ok, that is a good point. I will research how much I can get the epoxy resin for. They do sell the West System epoxy, I just remember it being much more expensive than in the US. I will check. Thanks!
     
  6. rxcomposite
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    rxcomposite Senior Member

    Where are you located? Isn't "kasko" the upper part? "Baol" is the bottom part, the dugout.
     
  7. rxcomposite
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    Location: Philippines

    rxcomposite Senior Member

  8. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    Not a good plan.

    Take your boat to freshwater a week and kill the worms.

    Run it back home and inject all the holes with epoxy. Use fumed silica for a thickened cap on top.

    Paint the boat every season with antifouling loaded up with copper sulfate.

    Add an untreated, unpainted skeg as a peace offering, aka worm shoe. Worms will eat it instead. Just be sure to remove and replace it before they blow through the poisons.

    Sea Worms! https://www.boatdesign.net/threads/sea-worms.21171/page-2
     
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  9. Rumars
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    Rumars Senior Member

    First things first, the structural integrity of your boat is compromised. There is now more hole then wood in the dugout part of the hull, and it can break anytime. If you shoot expanding foam into the visible holes the pressure will probably break the wood. The solution is simple, the dugout "kasko" must be replaced. You have three replacement options:
    1. Wood of the same species, sheated with fiberglass, metal or plastic.
    2. Wood with a better teredo resistance (there are a few species available, but it's impossible to determine in advance how well an individual log will perform).
    3. An all fiberglass lower hull. This is a common strategy in other places that use dugouts. You can use the existing hull as a male form to laminate the new. In order to save resin and glass you can incorporate wooden stringers and frames, but you loose the smooth inner bottom.

    What you choose depends on local prices, so find out what the different options will cost you.

    To answer your other question, the sheating is tacked with either short, wide head nails (commonly used for roofing or upholstery), or with wide staples. They can be copper, galvanized steel or stainless steel, depending on budget.
    Fiberglassing over a male mold is always somewhat "lumpy" and has to be made smooth by filler and sanding.
     
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  10. CaramoanReef
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    Location: Caramoan, Camarines Sur, Philippines

    CaramoanReef Junior Member

    We are in the Bicol Region, about 4 hours from Naga City. The people here have always called it "kasko".
     
  11. rxcomposite
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    rxcomposite Senior Member

    You are not too far from Manila. There are 3 major resin and fiberglass supplier here in the Philippines. The most complete is Polymer Products Philippines and seems to have branches everywhere. They carry also West System epoxy. Stay away from epoxy as it is prohibitively expensive. Cost of repair will probably be more expensive than replacing the rotted part.

    I will write up something later in the day to salvage/repair whatever remains of your banca. How big is it?
     
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  12. portacruise
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    portacruise Senior Member

    What do the other locals do to solve the same issues, and why would you want to approach it differently? Are there Bargains to be had in the used boat Market, like in the USA where used fiberglass boats can be very low cost or even free depending on how much resources and effort one is willing to expend on repairing?
     
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  13. rxcomposite
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    rxcomposite Senior Member

    You must have the old style banca whose underside is a dugout, a hollowed log. This is no longer available as logs are prohibited. Modernized banca have timber as a keel where lumber frames are secured and skinned with marine plywood.

    Just to make sure we are on the same page, I will assume you will be repairing the dugout.

    Invert the banca and sand with 36 grit all paints up to 50mm above waterline. Gouge out all cracks and replace rotted portion with a piece of the same specie of wood. Glue the piece with local Pioneer epoxy. The slow drying 2 part pink one that cures slowly. About 24 hours. This is what the locals use.

    Leave it in the sun for about three days. Most termites will die under the hot sun. Others use blowtorch to speed up the process. Just enough to heat the wood and drive out the termites. Heat it slowly, don't burn it.

    Treat the wood with anti termite solution. Look for the one made by Century Chemicals. It is a white liquid available from hardware stores. Half a liter will do as you will be mixing it with 10 parts water. If you can't find it, order online from Shopee or Lazada the brown stuff anti termite solution. Cost about P500 for half a liter. I think it is made by Bayer. Read the instructions carefully. It is very toxic and you must use PPE. Use gloves and old clothes as you are instructed to dispose of it after use.

    Use a large syringe to inject the solution in all holes and finally wet the whole surface with the remaining solution. Let dry for about 2 days.

    Fill all termite/nail/screw holes with excess epoxy or resin mixed with fumed silica (Cab o Sil). Prepare the surface with 60 grit sandpaper and drive small copper/brass/stainless nails 50 to 90 mm apart. Small means about 12mm. Keep the head proud by about 1 to 1,5 mm. I prefer galvanized staples as I have industrial stapler, not the office variety. Pry it so there is gap between the staples and wood.

    Hot coat by applying Ortho resin. Ortho is thick and viscous, you can dilute it with styrene monomer. It is also cheaper than Iso resin but you will have to paint it afterwards to protect it from UV light.

    Apply CSM cloth and thoroughly wet it with resin. Start with 300 gr/m2 then CSM 450. Because your wood is already compromised you need to build it up to around 3mm thick. About 4 layers. Sand lightly and Finish off with 2 layers of WR 600. First one laid up at 45 degree and last one with 0 degree. Add wax solution for the last layer to keep it tack free. Laminate to about 50mm above waterline. to keep it looking good, Cut with a straight edge the laminate while it is still soft. Don't cut too deeply damaging the wood.

    These are bulky items and if you are in a remote area, visit the local bus company and ask if they accept shipping. Cheaper than a courier. You have to pick it up in the bus terminal though.

    Dewax with acetone or lacquer thinner and sand with 60 to 80 grit, finish painting with Cord Marine Epoxy paint. The local favorite, available from hardware stores or marine suppliers.. Paint the inside with gray (or color of your choice) with Cord epoxy.
     
    Last edited: Feb 19, 2023
  14. Rumars
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    Rumars Senior Member

    From this I understand he has teredos not termites. In wich case I doubt there will be much wood left to patch and sand.
     

  15. rxcomposite
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    rxcomposite Senior Member

    Only when it is like this. Time to ditch. istockphoto-484327044-612x612.jpg
     
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