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Thread: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

  1. #71
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    You are right, I should try a bit harder. It's a huge amount of new vocabulary, and up till now I was concentrating mainly on understanding how this all works together and concentrate on what is important for my project when reading, and the proper terminology somehow disappeared in the background.

    Really excited now, someone told me today he's seen oak in a place not far from here. I need to replace some of the floors in the aftcabin, and, if he is not mistaken this would be awesome! Will go there tomorrow to find out, I've been keeping my eyes open for oak more than a year now!!!!

  2. #72
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    I have to check, but I think 30mm planks can take 6mm nails. Ringed nails are good, maybe just as good as square boatnails. I have never seen square boatnails in monel or silicon bronze, only galvanized or copper so ringed nails are probably your only choice.

    Why so excited about oak? The Gambala you have been using is just as good and maybe better. Oak is only used because it is local and cheap and nothing better was available in Europe for a long time. Today a better local wood is black locust (robinia pseudoacacia) (acacia-bastarda, acacia-branca or robinia in portughese). Another similar species to oak is sweet chestnut, but it's also acidic and full of tanins and eats galvanized fasteners exactly like oak. Sometimes you have to use oak because there is no other choice but if I could choose oak would not be first on my list.

  3. #73
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Oh, I didn't know that! Quite a long while ago I was reading about oak. There it was said it's the typical material for frames, that it's hard and rot-resistant, that it eats steel-fasteners and that it causes problems with some other wood-species, larch was not one of them. I don't remember where I have been reading this, and although I've been looking for confirmation of the last statement for ages now, I can't find it anywhere.

    As Tonga's frames are oak, I thought I can't do something wrong in replacing an oak floor with an oak floor. That's the reason I was seaching for oak. If the Gambala I've been using is superior, even better, especially as I've still got some 40 mm and 35 mm planks in my workshop. There will be bedding-compound between the two anyways, so even if they would like to start a little fight with each other the bedding-compound will hopefully keep that under control. I'll still go there and have a look, also to find out what kind of other species they have, can come in handy one day! Also, I've got a rental car at the moment and that facilitates transport and moving around and hunting for materials tremendously.
    Last edited by Dody; 07-14-2017 at 05:17 AM.

  4. #74
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Interesting that you mention Oak being cheap, it wasn't in this place. Just for comparison, this place charges for the same quality Gambala I had from the other place 1310 Euro per m3, Oak 2235 Euro per m3. Without VAT that is and both in 40 mm, and I'm sure the price would be less if I bought more. The interesting thing with this place is the many different species they have available. They've got Sucupira, Wenge, Faia, Cerejeira, Nogueira, Casquinha (the same stuff I've been using for some of the planks aft), Riga (Pinha Amerciano), Castanha, Mognu (Sapelli), Tola, Apezelia, Motene, Freixo, Iroko and Kambala. When the guy showed me the different stacks of wood he instantly mentioned that it would only be possbible to choose from the wood in stacks already open till they are sold, and only then they would start with a new one. I remember in the other place, we were there for hours shifting timber till we had found the right ones. This doesn't seem to be possible in that place

    I had a look at the timber in my workshop first and found out that both 40 mm planks are just a bit not wide enough (20 mm missing), because I could get 3 floors out of one plank with the correct width. We found a perfect one in the shop, but 3.10 m wouldn't fit in my rental-car and I didn't bring a template so we would shorten it in the correct angle. Very glad about that, because, on coming home I started again with my investigations about Oak. In my ignorance I didn't ask which type of Oak it is they are selling, and I found this interesting video:



    Last edited by Dody; 07-14-2017 at 05:55 AM.

  5. #75
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Just forget the oak and stick to Kambala escura, or use Iroko if you want. Mechanical properties are about the same, moves less and is more durable than oak.

    Oak prices are subject to local variations. The price seems average for 40mm select & better quality kiln dried english oak (quercus robur) or sessile oak (quercus petraea) from a reseller. I can get similar 40mm slash cut at the local wood supermaket for 100 euros cheaper including VAT, but there is ample supply here. Going to the sawyer would be cheaper of course.

    When buying wood in a foreign language always ask for the scientific name. Casquinha for example is scotts pine, castanha sweet chestnut, freixo ash.

  6. #76
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Right, gonna make the template now and drive over to Caldas da Rainha to get the Gambala from my other distributor. Much cheaper, he's only charging me 800 Euro per m3 plus VAT.

    By the way, the nails I was thinking of using for the plank/frame-connection are these ones (so far as prices are concerned the less expensive, even though the British Pound is quite low at the moment):

    http://www.toplicht.de/en/shop/boots...siliziumbronze

    I still keep wondering if screws would be better. But first of all I'll never be able to get to them once the plywood and fibreglass is on. Then, pre-drilling for screws takes more time than for the nails and I think banging the nails in might be slightly faster too.

    And from tomorrow on, one week holiday. My parents are coming over for a week to visit me !

  7. #77
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    I woud stay with galvanized. Fewer problems that way considering the mass of iron your boat has. Cheaper also. They will last another 50 years (even longer if the boat is dry, and I would expect dusting the bilges in a cold molded boat). 30mm planking is ok with a 7mm screw, so a 5-6mm nail should also be ok. Toplicht also sells galvanzed boat nails, but the lcal chandlery probably also has them.

    Ask the distributor for the latin name of Gambala.

  8. #78
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Unfortunately I found your message when I was back home, so didn't ask about the latin name. I can try via telephone, but my Portuguese is not good enough yet to convert the answer into the proper letters - so, much better to ask next time I'm there. It was the same as before, Kambala escura and Zazange in the bill. 40 mm he had only in 4.45 m lengths at the moment. Remembering Spain where during 6 weeks in summer nearly nothing could be had, and the fact that I need heaps more anyways, I found 4 nice planks and they'll bring them to me with their truck on Monday. Concerning the price-difference to the place where I was yesterday: I'm getting the same discount as Albertino, the shipwright, which the other place of course didn't offer.

    With galvi or not galvi, I'm really not sure (happy I still have plenty of time). First of all to imagine Tonga with a bone-dry bilge after 20 years of sailing her with always having water coming in from somewhere feels pretty surreal. Sure, in a way, like probably everybody else, I would like her to be dry. Certainly, what I am planning on doing will help to achieve it and I can assure you I will try more than my very best. But we are talking boats, and with boats you never can be certain of anything.

    With all the smaller and bigger jobs I've been doing on her over the years, and also now, with the dismantling, I came across quite some red-coloured screws and bolts in a state of desintegration, but also a few bolts and screws which were kind of bronze-coloured and actually not in a bad state. I've always tried to find the time to find out more about the interaction between metals but somehow it never happened. One thing I really dug into out of necessity are skinfittings and seacocks. It was in 2002, Tonga was in the boatyard for new antifouling when my foot very slightly brushed past a seacock. Next thing that happens was "plop", it fell over, and I could see the concrete of the yard through the hole below me. Needless to say I immediately replaced every single skinfitting and seacock on Tonga, with fittings I bought at the chandlery, only to find out about a year later that nowadays it's very hard to find proper bronze skinfittings and seacocks, most of the ones sold have a high content of brass, the zinc dissolves with the seawater and what is left is some copper that has no resistance at all. Consequently skinfittings and seacocks have to be replaced every 5 years.

    In the meantime I found a supplier for proper bronze-seacocks and skinfittings, the price is nearly double that of the ones you get at the chandler's, but in my opinion money more than well spent. Needless to say that this is what I'm gonna install the moment the hull is ready. They still have to be checked regularly, but I'm having trouble to keep my tongue when someone tell me "my skinfittings? Oh, they are fine! They looked a bit green, I scratched a bit and it looked red, so I took the wirebrush and gave them a good scrub and look how nice they turned out".

    So now, back to bronze nails or screws ... Galvi????? I'm really stuck with this!
    Last edited by Dody; 07-15-2017 at 06:51 PM.

  9. #79
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    I would have loved to use Monel or Silikon Bronze, but several hours "googeling" the question have managed to finally convince me that it doesn't seem to be a good idea. I've got heaps of mild steel (attached to the floors to give one example) and "ex" galvi-fasteners everywhere on my boat. There is no guarantee that I will not hit something in the future and seawater will find it's way in or that I might have a leak from pipes or whatever. There should be no problem with the 2 metals at all as long as Tonga is bone-dry, but there is no guarantee for this being the case. As soon as seawater should manage to get in, galvanic corrosion because of the presence of Silikon-Bronze will destroy everything steel I've got on the boat and I don't know of a way around it. Certainly, if I replace every mild-steel or galvi bolt, driftbolt and whatever, it wouldn't matter if nails holding the planks on the frames which are already doubled up with Silikon-Bronze-fasteners will get destroyed. They would be surplus in this case anyway. But how about the driftbolts and bolts I don't know about and which I didn't replace by accident as I don't know they are there? How about the ballast-keel made from mild steel? Please correct me if I'm on the wrong track, but right now it looks as if galvi-fasteners are the only way to go.

  10. #80
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Galvo should outlast your use of the boat.
    Much as you love her, you should realise that her construction methods are so eccentric that she will not have much resale value. So do what she needs now and don't think past 30 to 50 years of life.
    It really is quite difficult to build an ugly wooden boat.

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  11. #81
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Thanks Nick, re-sale-value is of no concern, not for me, not for my family. My eldest Nephew loves Tonga as much as I do. The moment I sail over the horizon I would like to leave her to him in as trouble-free a condition as possible by human beings.

    By the way: is there any reason why it seems to be impossible to find out anything about beamshelves? I've nearly finished my second boatbuilding-book without anything mentioned about them, and looked at the index of the 3rd one but nothing mentioned there either. It doesn't matter that much as I've bolted each deckbeam from the top to the spacers in 2 or 3 places, and bolted the knees to the frames and deckbeams as well, but somehow I would like to know more about what beamshelves are meant to do apart from offering something to screw the deck on.
    Last edited by Dody; 07-19-2017 at 08:23 PM.
    fair winds, Dody

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  12. #82
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Quote Originally Posted by Dody View Post
    Unfortunately I found your message when I was back home, so didn't ask about the latin name. I can try via telephone, but my Portuguese is not good enough yet to convert the answer into the proper letters - so, much better to ask next time I'm there. It was the same as before, Kambala escura and Zazange in the bill.
    This helps with the more common words. https://translate.google.com/
    It doesn't get all of them, but this list it gets about half:
    From Portuguese: Wenge, Faia, Cerejeira, Nogueira, Casquinha Riga (Pinha Amerciano), Castanha, Mognu (Sapelli), Tola, Apezelia, Motene, Freixo, Iroko and Kambala.
    To English: Wenge, Beech, Cherry, Nogueira, Casquinha Riga (Pinha Amerciano), Chestnut, Mognu (Sapelli), Tola, Apezelia, Motene, Freixo, Iroko and Kambala.

    Some matched well in this Portuguese flooring company site: http://www.strongexport.com/en/produ...icans/nogueira
    Rua de Porto D'Ave, nº 425, Taíde 4830-755 Póvoa de Lanhoso
    Nogueira; Juglans nigra
    , eastern black walnut
    Pinha Amerciano; Pinus Taeda, loblolly pine
    Tola, Gosweilerodendron Balsamiferum; Tola Branca, N' Tola, Tola Blanc, Emolo, Agba, Sinedon, http://lesserknowntimberspecies.com/species/item/208
    Apezelia, Afizélia is one of the thirty species belonging to the family Leguminosae; Afzelia Africana Smith http://www.wood-database.com/afzelia/
    Motene,
    Freixo http://www.strongexport.com/pt/produ...ricanas/freixo Ash
    Kambala 'is best known for Iroko' Chlorophora Excelsa Other Common Names: Semli (Sierra Leone, Liberia), Odoum (Ghana, ivory Coast), Rokko, Oroko (Nigeria), Abang, Mandji (Cameroon, Gabon), Mereira (Angola), Kambala (Zaire), Mvule (East Africa). More names http://gabonwood.net/iroko/

    Motene:
    Mutenye(Guibourtia amoldiana)?
    Mopane?
    Colophospermum mopane (also Mopani).

    EDIT KAMBALA ESCURA is not iroko, I stand corrected, Rumars was right, it is Albizia ferruginea.
    Iroko is also called kambala, but not kambala escura.
    According to Plant Resources of Tropical Africa Kambala escura is Albizia ferruginea. The link has lots of information on the wood. It is rot resistant, hard and reasonably strong. The properties listed are higher there than the wood database, or ITTO.
    The trouble with common names, listed by ITTO for Albizia ferruginea alone:.
    Common Names
    Murase (Togo); Kulo (Ghana); Awiafu-samina (Ghana); Yatandza (Côte d`Ivoire); Muchole (Uganda); Omulera (Tanzania); Omulera (Kenya); Yatandza; Sakachi; Newei; Musase; Muchole; Kulo; Iatandza; Evuvus; Ayinre; Awiemfo-samina; Awiafu-samina; West african albizia (United Kingdom); Okuru (Zaire); Elongwamba (Zaire); Zazangue (Angola); Sifou-sifou (Congo); Evouvous (Cameroon); Ayinre-ogo (Nigeria); Okuro (Ghana); Aviemfo-samina (Ghana)
    Last edited by MN Dave; 07-22-2017 at 12:32 AM. Reason: correction
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  13. #83
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Quote Originally Posted by Dody View Post
    Thanks Nick, re-sale-value is of no concern, not for me, not for my family. My eldest Nephew loves Tonga as much as I do. The moment I sail over the horizon I would like to leave her to him in as trouble-free a condition as possible by human beings.

    By the way: is there any reason why it seems to be impossible to find out anything about beamshelves? I've nearly finished my second boatbuilding-book without anything mentioned about them, and looked at the index of the 3rd one but nothing mentioned there either. It doesn't matter that much as I've bolted each deckbeam from the top to the spacers in 2 or 3 places, and bolted the knees to the frames and deckbeams as well, but somehow I would like to know more about what beamshelves are meant to do apart from offering something to screw the deck on.
    A starter for 10.
    http://www.diy-wood-boat.com/Deck_Be...lampBeam_Shelf
    They provide support to deck beams without constraining them, hatches, and cabin ends to the location of your frames. They also contribute to the strength of the hull by forming a part with the deck plank of the top flange of the girder that is your hull.
    It really is quite difficult to build an ugly wooden boat.

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  14. #84
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    Quote Originally Posted by Peerie Maa View Post
    A starter for 10.
    http://www.diy-wood-boat.com/Deck_Be...lampBeam_Shelf
    They provide support to deck beams without constraining them, hatches, and cabin ends to the location of your frames. They also contribute to the strength of the hull by forming a part with the deck plank of the top flange of the girder that is your hull.
    Thanks again Nick, I was hoping to find different systems which apparently do not exist. I do seem to start to understand more and more of what you mean with "eccentric built":

    For some reason my deckbeams are ending on the inside of the beamshelf and the top level with it!!! I haven't got the slightest idea how they might be held in place. Sure, they are sitting on top of the frames, so they can't sag. The 3 new ones were fitted by the shipwright and I didn't pay too much attention to it then.
    What I do remember, somewhere on the starboard-side, there was a shim between a deckbeam and the beamshelf in a bad state and I replaced it, finding 2 nails going into the deckbeam coming from the sheerstrake (hey, I managed to use the proper term ��!). Could it be that these 2 nails were the only thing keeping the deckbeam from moving? And actually, when it was done this way with this particular deckbeam, am I wrong to suspect the same system with all the other deckbeams? Alright, they are now held in place by my solution of bolting them with knees etc. to the frames, and also because the deck is screwed to the beamshelf and the deckbeams. But to be honest, it feels pretty scary to me and it feels like a miracle that I survived this bloody hurricane so well. Also, in Spain on a mooring, I got a pretty hard hit by a Princess 25m out of control in a force 11 which caused quite some damage to the Princess, but apart from my midships-cleat getting destroyed and damage to the paint no structural damage on Tonga. It doesn't make sense.

    Sure, because of the typical shape of a boat, in front of midships (in theory) they would only be able to escape towards the aft and vize-versa aft of midships when the fasteners of the frames fail ...

    Right now I guess that by accident he cut the deckbeams too short - or has anyone heard of or seen a similar construction in the past?

    Nearly all of my new deck is laid now, only 4 or 5 m on the aftdeck missing.

    Would it help to bolt timber to the "beamshelf" with a tight fit between each deckbeam? Who has got a brilliant idea to overcome this problem?

    Thanks heaps in advance!

    Sent from my SM-G900FD using Tapatalk
    Last edited by Dody; 07-22-2017 at 09:31 AM.
    fair winds, Dody

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  15. #85
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Here are some photos from a while ago:






  16. #86
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Your ply gussets, and the ply deck well fastened on top will tie her together. Don't skimp on the fastenings though as they will transfer the shear loads from the deck to the hull that resist the boat working in a sea way.
    It really is quite difficult to build an ugly wooden boat.

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  17. #87
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Quote Originally Posted by Peerie Maa View Post
    Your ply gussets, and the ply deck well fastened on top will tie her together. Don't skimp on the fastenings though as they will transfer the shear loads from the deck to the hull that resist the boat working in a sea way.
    Do you mean the amount of fastenings or the material they are made from?

  18. #88
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Quote Originally Posted by Dody View Post
    Do you mean the amount of fastenings or the material they are made from?
    Thicker the better, if you cant do thick, use more. What thickness deck ply are you using?
    It really is quite difficult to build an ugly wooden boat.

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  19. #89
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    It's 12 mm screwed and Sika-glued onto the deckbeams and beamshelf, then 3 layers of 6 mm epoxy-filler-glued on top, held with stainless staples till the epoxy has cured (but I leave the stainless-staples in) = total thickness 30 mm. On top of that probably 2 layers +/- 45 Bidiagonal Fibreglass 420 gr/m2 with Epoxy, will start once the decking is completed.

  20. #90
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    The scantlings rules recommend 18 to 20 gauge or 5/16th diameter. For a conventionally carvel planked boat there would be two fastenings per plank, which would space about 21/2 inches apart.
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Thanks Nick, that sounds very close to what I have been using. Gosh, so glad I didn't mess this up!

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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Quote Originally Posted by Phil Y View Post
    I suppose potentially the plank to ply bond shears away, the ply planks move apart and the glass sheathing is torn. Or it all just firms up in a stiff stressed monocoque structure, with no breakage. My boat is 50 feet, built in 1974. Strip planked, edge glued and nailed, and glassed on the outsid from new. Just paint inside. Built with Celery Top Pine, which is quite stable. I occasionally get a fine crack in the sheathing due to movement in the planking, cracking the glass. I understand there is a fine art to traditional caulking in carvel construction. Too soft and it leaks, too hard and it starts breaking frames.
    Hi Phil, I'm just past reading the planking-section of my "Boatbuilding Manual" and I found the planking method your boat is built with, so now I have a tiny little idea how strip-planking is done in general !

    Out of curiosity and to understand more about the whole subject, but also because we're roughly the same length (although I guess I'm several tons more heavy than you), could you tell me what the thickness of your planks is and the sideings and mouldings (thanks Nick, still remember to use these terms for the dimensions of the frames!) of your frames? If I get that right, your glass is glued directly to the planks, no plywood in between the two? And is the sheathing done with Polyester or with Epoxy?

    And there is something else I would like to know: These fine cracks that happen in the sheathing from time to time. Well, sure, you won't notice instantly, but would you trace them down to some sailing her hard for more than a bit (Bass Strait and the Tasman Sea do have a bit of a reputation!), or would you reckon it has more to do with humidity? If humidity I guess it would happen more at certain wet times of the year (I was in Tassie in 2006 or 2007 for 8 weeks and had no rain at all!) Are there areas/zones in the boat where it happened more often and areas where it happened less often?

    Sorry to ask you all these questions, but I find this super-interesting and the possibility to ask someone about this doesn't happen too often!
    Last edited by Dody; 07-23-2017 at 06:40 PM.

  23. #93
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    While happily working away today trying to find my rhythm back after this week with the visit from my parents, suddenly a subject crossed my mind:

    Drainage and Ventilation

    You probably all remember that steel-boats usually rust from the inside to the outside. To overcome this, good steel-constructions have lumber-holes everywhere the stringers meet the frames. Thus, water can run down the hull into the bilge and be pumped out instead of standing there doing it's destructive work.

    Admittedly there is far less condensation in a wooden boat. Still, water does get in and if it's only because something went wrong.

    Example from today: I finally removed the old ventilation-hose leading from the engine-room to the aftcabin. Of course I had completely forgotten that some while ago when replacing my tent and the deck on this side open, it rained quite heavily. Consequently water had collected in this hose and was still there. Well, till I lifted it and tried to pull this heavy clumsy thing out between corners.

    No worries at all at the moment: the water just runs along the planks till halfway of the engine-room, then runs down the hull (between planks and plywood) where it gets channeled to run into the bilge, and can be pumped out. Easy.

    This won't be the same when the new plywood goes in. I can't attach the new plywood to the planks without anything in between, whatever this might be. But: using bedding-compound, epoxy or no matter what - water will never again be able to run between the planks and the plywood into the bilge. It will be stuck there on top of the plank, eventually dry out, but in the meantime trying to do it's nasty work. Sure, especially with the bigger gaps between planks the process of drying out should be faster. Also, because of these bigger gaps running from stem to stern, ventilation has never been an issue.

    Certainly, nobody would dare to cut lumberholes into the planks and weaken his whole structure. But how about epoxy-filler-glueing - for example - inox-tubes with maybe 10 mm inner diameter and as long as each plank is wide somewhere midships on each side of the boat? They for sure shouldn't to be in one single line, but could be staggered over the area of maybe 6 frames or so.

    Crazy idea?

  24. #94
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Quote Originally Posted by Dody View Post
    Crazy idea?
    Yes, it is.

    She has not rotted yet in how long, has she? Just ensure that she is well ventilated and well painted.
    The only other option is to glue splines into all of the gaps as you prepare her for the new plywood skin.
    It really is quite difficult to build an ugly wooden boat.

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  25. #95
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Yes crazy ideea. As Nick says you either live with it or convert to full strip plank. The only way to channel water of the stringers that I know of is with stringers that are not parallel to the waterline, but inclined towards the bilge. Some dutch plywood boats had them before epoxy time.

  26. #96
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    Default

    Sure, no worries, I will push heaps of paint around inside and keep it under control, and I do like to keep the gaps to enhance ventilation, so no splining unless it really has to be for other reasons.

    But, honestly, don't you think the absense of rot after 57 years has to do with the possibility for water to disappear straight into the bilge?

    Sent from my SM-G900FD using Tapatalk
    Last edited by Dody; 07-24-2017 at 09:15 PM.
    fair winds, Dody

    "They did not know it was impossible so they did it" - Mark Twain

  27. #97
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Quote Originally Posted by Dody View Post
    No worries, I will push heaps of paint around inside and keep it under control, and I do like to keep the gaps to enhance ventilation, so no splining unless it really has to be for other reasons.

    But, honestly, don't you think the absense of rot has to do with the possibility for water to disappear straight into the bilge?

    Sent from my SM-G900FD using Tapatalk
    What happens if you wash or spray with water? You could probably benefit from washing the debris from between the stringers, and that would let you see how well it drains.

    If the water tends to drain poorly, perhaps a treatment with Timbor or similar material would provide some residual protection. http://seashorepestcontrol.com/timbor-treatment/

    My only comment on the unusual fixes to the unusual structure is that I agree with Nick and Rumars. Within the limits of my expertise, you seem to have a good understanding of the situation and are doing a good job. In case you missed the edit to my last post, I finally found a reference confirming Rumars early identification of kambala escura.
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  28. #98
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Quote Originally Posted by Dody View Post

    But, honestly, don't you think the absense of rot after 57 years has to do with the possibility for water to disappear straight into the bilge?

    Sent from my SM-G900FD using Tapatalk
    Not really, the gap, and I do hope that there is no real gap, between the ply outer skin and strip planking will be poorly ventilated and damp, a breeding ground for rot
    It really is quite difficult to build an ugly wooden boat.

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  29. #99
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Quote Originally Posted by MN Dave View Post
    What happens if you wash or spray with water? You could probably benefit from washing the debris from between the stringers, and that would let you see how well it drains.

    If the water tends to drain poorly, perhaps a treatment with Timbor or similar material would provide some residual protection. http://seashorepestcontrol.com/timbor-treatment/

    My only comment on the unusual fixes to the unusual structure is that I agree with Nick and Rumars. Within the limits of my expertise, you seem to have a good understanding of the situation and are doing a good job. In case you missed the edit to my last post, I finally found a reference confirming Rumars early identification of kambala escura.
    Awesome, I love your idea !!! If it wasn't for the fact that I do want it all to dry out nicely, and, as I'll have proper acess from the outside soon, I won't. Also, maybe another product, the guy with the respirator makes me believe it's bad news for us people too, and as far as I know there is no termites or ants in my wood. Ahem, saying this, I would have noticed their presence, wouldn't I?
    Actually, now that you mention it: when I was in Madeira the guy in the berth next to me had a Swan (Swedish-built FRP sailing-boat). We were both preparing to sail to the Azores, one of his most important tasks was to chuck water and dishwashing-liquid into his bilge for the voyage, so the movement of the sea would nicely slosh it around and upon arrival he only has to pump it out and has a clean bilge. He left 2 days earlier than me, so I couldn't watch what was coming out. But when we met up in Ponta Delgada (Sao Miguel/Azores) his bilge was spotless .

    Thanks, I found your post confirming it. And as far as understanding of the situation is concerned, thanks. Unfortunately there are still huge black areas I don't know anything about and I'm very happy that you all make a big effort to help me with that. Thanks again!!!
    Last edited by Dody; 07-25-2017 at 07:46 AM.

  30. #100
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Timbor is a borax based chemical which is basically harmless to mammals, but kills insects and fungus.
    Polybor products were used to rot proof Scott's Discovery during her refit for display at Dundee.
    It really is quite difficult to build an ugly wooden boat.

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  31. #101
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Hm, that doesn't sound too bad actually.

    Would that still be state of the art today in Europe, or what are people using today to protect their wooden boats?

    I've been using this one so far, but of course, I will only find out that it's no good the moment I find a problem



  32. #102
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    NOTE ADDED LATER: Xylophene is VERY toxic. You MUST follow the safety instructions, including the wearing of protective gear and an appropriate breathing mask. As an alternative to xylophene it has been suggested to me that boron can be used (I have no experience of this, please research on the internet if you are interested).
    from http://www.france-renovation.com/beams-and-woodwork/12
    It really is quite difficult to build an ugly wooden boat.

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  33. #103
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Quote Originally Posted by Dody View Post
    Hm, that doesn't sound too bad actually.

    Would that still be state of the art today in Europe, or what are people using today to protect their wooden boats?

    I've been using this one so far, but of course, I will only find out that it's no good the moment I find a problem

    Borax and similar borates are the old industry standard for mold remediation. There are newer products like Xylophene that are also used and are very effective. From what I could find in a report that I lost the link for, Xylophene was one of the best for killing termites. It is also a fungicide, but there was only a brief summary in English. Overall, it looks like a good product to someone who can't actually understand the language.

    The mask worn for Tim-Bor could be the same particulate filter used for any irritating dust. You need an organic vapor respirator for Xylophene. The borax in Tim-Bor is very much like the borax used to clean laundry. You don't want to breathe ANY dust that you are spraying all over the place. Anyone who sprays anything for a living and wants to keep living should avoid everything that they are exposed to every day on the job.

    Safety data sheet
    FICHA DE DADOS DE SEGURANÇA Nome: XYLOPHENE SOR2 EXTREME
    http://www.bondex.pt/Data-Sheets/MSD...Xylophene-SOR2
    Irritating to skin.
    Flammable.
    Harmful: may cause lung damage if swallowed
    It looks like a modern fungicide or insecticide to someone who doesn't speak the language, but sees similarities in the chemical names. It contains >50% Naphtha, which is OK to spray in well ventilated areas, but a bit like petrol in a confined space.

    Tim-Bor Safety eata sheet:
    http://www.biconet.com/crawlers/info...TimborMSDS.pdf
    Emergency overview: Tim-bor is a white, odorless, powdered substance that is not flammable,
    combustible, or explosive and has low acute oral and dermal toxicity.
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  34. #104
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    Thanks for all the information. I've now been reading both, the Xylophene and the Tim-Bor saftety-sheets and have the feeling that there is not that much of a difference between them. Tim-Bor powder can turn into explosives when it comes into contact with certain chemicals or gasses. As I'm not good with chemicals I haven't got a clue how likely this might be to happen. Xylophene is flammable, but no danger as long as the container is closed and not damaged. Both cause a risk for plants and aquatic animals when lost in the environment, and with both you are meant to wear protective gear.

    In the datasheet for Xylophene it says you need the protective mask (A1, A2, A3 Filter, browncoloured) when ventilation is not good enough. I've got this type of mask, I've even replaced the filter once, I hate it, but I have been using it. One thing I will never do again is spraypainting this stuff inside my boat - even with full gear and mask and googles it was horrible. Since then I've been applying it with a brush and that works fine. Most of the time I can apply it in the open air, I use gloves, make sure the wind comes from behind and don't use the mask. The smell is quite distinct, as long as I can't smell it I'm not getting anything.

    I've got to go to Alcobaça and the farm-cooperative tomorrow anyway, I'll have a look if they might have this Tim-bor. On Internet it's a lot cheaper than Xylophene (Xylophene is around 60 € the large tin)

  35. #105
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    Default Re: Wood - Plywood - Epoxy bond, re-building my ketch Tonga

    From Wikki (edited)
    Other uses for Borax

    • Anti-fungal foot soak
    • Treatment for thrush in horses' hooves
    • Swimming pool buffering agent to control pH
    • Was traditionally used to coat dry-cured meats such as hams to protect them from becoming fly-blown during further storage
    • Is found in some commercial vitamin supplements
    • Used in the treatment or prevention of wood rot in classic wood boats


    It really is quite difficult to build an ugly wooden boat.

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