Did a dream got shattered?

Discussion in 'Boat Design' started by BertKu, May 16, 2010.

  1. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Bert, after living almost 18 years on the Adriatic shore, I have replaced nearly all the wood with plastic or metal because I was tired of fighting a lost battle against sea spray in winter and scorching sun in summer. The only objects that seem to be impervious to this climate are untreated Meranti 50x50 mm I bought in a garden center in 1994.

    The farmers here who built their own houses used pine beams which they put in a gutter and the whole family pissed on them for at least a year. Ureum seems to be a good and not overly expensive wood preservant.
     
  2. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Mmmmmmhhhh, Thanks for the information, but I don't think my wife will appreciate to know what I did to the interior of the boat. I rather use Mono Ethylele Glycol. The wife will be happier. (And so am I, but you are totally right, it is a solution).
    Bert
    P.S. I picked this up from the WIKI :Ethylene glycol has seen some use as a rot and fungal treatment for wood, both as a preventative and a treatment after the fact. It has been used in a few cases to treat partially rotted wooden objects to be displayed in museums. It is one of only a few treatments that are successful in dealing with rot in wooden boats, and is relatively cheap
     
    Last edited: Apr 19, 2012
  3. Tad
    Joined: Mar 2002
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    Location: Flattop Islands

    Tad Boat Designer

    Bert,
    We had a PL48 built in South Africa a few years back. All structural members are laminated African Mahogany and strip-planking is of Japanese Cedar. The entire exterior of the boat is sheathed with fiberglass set in epoxy. This structure, if taken reasonable care of, should last much longer than you or I.

    Realize that even here in the temperate rain forest finding quality boat building material is not easy or cheap. It's possible, but not easy.

    I don't know what your schedule is or even what fastening and construction method you are intending. But I would be very careful to test bonding of lamination before using any preservative. In general I try really hard to use materials that either become inert or are not poisonous to humans or dogs (which lick stuff).
     
  4. ImaginaryNumber
    Joined: May 2009
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    Location: USA

    ImaginaryNumber Imaginary Member

    You might consider using plastic nails or staples, such as these:

    http://www.raptornails.com/
     
  5. tugboat

    tugboat Previous Member

    Bert-- try not overthink things---im the master at that and you arent allowed to challenge me for the title..!!!:D

    Seriously---less thought --i don this all the time --overthink everything to analysyis paralysis. thinking is good --but in moderation- trust me on this--
    whatever you choose will have tradeoffs..but choose you must--read my threads to see the trouble it can cause...:)
    i hate to say this because its been said to me and i didnt like it...

    but it was correct info:" just start to build it" put one leg in front of the other--dont think and get going..(yea im being hypocritical here but when i DID eventually do this--it worked out fine.....
     
  6. BertKu
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    Location: South Africa Little Brak River

    BertKu Senior Member

    That is a wonderfull idea. I had a look at their website and registered myself. I assume , one has to pre-drill a hole, to have optimum result. The boat plans indeed called for nails at certain places. Thanks
    Bert
     
  7. BertKu
    Joined: May 2009
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    BertKu Senior Member

    Doug, It is not a matter of overthink. I learned an unbelievable lot of do's and don't do's from the forum members. Even if forum members have written something which maybe qusionable, I have learned from it.
    I have started.
    Bert
     
  8. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Hi Tad, First at all I like your website, it is easy to manoeuvre in it and get information. The hull I am building is similar to your 19' boat. I am building it with plans I bought from NZ, proven, maybe old fashioned, but solid. I am no youngster anymore who wants to speed and to build a boat for re-selling. Making the boat, trying to learn why certain things are done in a certain way, calculating any changes to the plans makes me tick.

    The 3 designs bought from NZ, I am able to understand, and able to make to the needs of my wife and myself. I was only disappointed with the after sales service when I accidental shredded a 1 page material list of the boat the forum recommended. Thus it was an omen for me to go back to the original idea I had. Maybe it is better for me as the shape is now the same shape as your 19' after manipulating and re-calculating all details. It pleases me. Nobody can crap me out anymore.

    To come back on preservations. I agree with you that one has to be careful. 80% of the pine wood in this country is treated in vacuum chambers, used for building and various other industries. I even know of somebody who made a boat from treated pine wood, surprising it is the cheapest boat probably in the world and is already for years and years in the seawater. But I have selected French Lloyds approved plywood and a dark red/brown Meranti wood for inside of the boat. For those parts with continuous contact with the seawater, even if it is coated, I need a more oily based wood like Rhodesian teak, or as you suggested African Mahogany.

    I am not so much worried about the dogs when I treat Meranti, after 12 dogs, we decided not to have dogs anymore. I am more worried, when I cut the treated wood I will have to use a mask, as the speed of the saw blade will create nasty fumes. The UV light from the sun will break down any poison over a period of time in the surface layer of the Meranti (not in the core) during the building of the boat and hull. Also I will have a layer of paint, varnish or wood stabilizer oil at the end. I will take up your tip for African mahogany and see whether I can get it easy in Cape Town, then I will make a final decision.
    Thanks for the input.
    bert
     
  9. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    however will we ever get termites on a yacht ???

    Even if you go dockside, never tie up , or use a power or water hose ,to create a gangway,,,,,remember Termites can fly!


    FF
     
  10. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    I woke up from my dream with a big grin (disappointing) on my face. I started to build the electrical drive train with brushless DC motor some 3 years ago, had enough problems to make it all work, all metal work had to be cut, drilled , milled by hand and when my wife told me with a twinkle in her eyes, the boat will be for sure ready when I will be 90, I decided to buy a hull. Although I stocked my garage with the finest marine plywood I could buy. It was a nightmare to cut a 2,5 meter by 1,25 meter sheets on my own. With a few chairs it did work, but it was too dangerous and cumbersome for 60 sheets to cut on a small table saw. I also had purchased 3 plans from NZ, although when I needed their help to sell me a material list for the correct boat, (I accidental had shredded one of the three material lists) they told me to jump in the sea. (that would have been the right hull) .


    I know what you will say. It is the wrong hull, too much drag, but you must see it my way.
    A) It is already seaworthy certified with 70% buoyancy.
    B) It was easy enough to have it re-fibre glassed and make it new and take the dents out
    C) Small enough to do testing with solar and electric propulsion inland.
    D) Should I be able to get better batteries with more energy per Kg in the future, I could easy convert the outboard to a planing condition with building a more powerful motor or put 2 more motors in the box in tandem. Torqeedo has already a powerful enough drive train to make a boat planing.
    E) Propcalc software program does not give much speed differences between displacement and speed boat planing hull.

    Here are my questions.
    a) Is it worthwhile to build a rounding transom with displacement rounding characteristics, to reduce drag, or is it not worth the effort and cost? I will then also improve CB and overall buoyancy. It will be bolted on the transom, I can remove it when no longer needed or if I wish to sell the boat.
    b) What is the best way to make a mould for this complex shape? Or should I make it straight away from strips, without making a mould?
    The attached sketch gives an idea what I like to build. I thought to use 9 mm ply for the top, and then cut strips of 6mm plywood and cross glue/fibre-glass them in this complex shape. I fill it up with special foam.
    Your input is really appreciated.


    Photo’s attached
    extension.jpg = what I had in mind.
    004.jpg = What I was planning to build.
    003.jpg= Transom with electric drive-train.
    Boat.jpg= What I bought and fixed up.
    chairs.jp= Struggling with big sheets
     

    Attached Files:

    Last edited: Nov 16, 2012
  11. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    A rounded butt does improve performance at displacement speed. But this extension is just a large toilet bowl; the open bottom will cause more drag instead of less and the water level in the bowl will rise to flow over the seat.

    Making such a contraption is a very tough job, especially if it should look as if it belongs there. I would make a female mold for the external shape from Styrofoam blocks, glued together to obtain the approximate shape, then shaped with a hair dryer and a wire brush. There is a special plaster for Styrofoam to obtain a smooth surface. The lid (toilet seat) must be made separately and installed after the extension has been attached to the hull. I would cut the Styrofoam mold in pieces and throw that in the extension before fastening the lid with Sikaflex and stainless screws.

    Good luck,
    Cornelis
     
  12. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Thank you Cornelis, I thought already that the gap where the motor/propeller swivels in and out, may have to be very well constructed. Indeed, If I make it as a scoop behind the prop, it will collect water and also drag. I have to be careful that the prop is not spitting too much water in that direction. I would have a fountain.
    I am able to lower the prop by 15 cm and could leave it open behind the prop and only have a bridge above the waterline. I have that special stuff, which, if the 2 are mixed, the "foam" rises tenfold in volume. Also This stuff it is approved by the authorities. I will experiment with Styrofoam and see how easy it is for me to make a mold.
    Bert
     
  13. tugboat

    tugboat Previous Member

    i hate to sound trite Bert- but thats what tugs have--your adding a counter stern... have you thought about something like this: (see attached image)
    it would greatly reduce drag at displacement speeds--downside(there always is one)- its hard to fabricate unless its frp or maybe strip plank or ferro-cement... in other words its not developable. not conic or cylindrical sections...or rather they are but they are then curved again...
    cheers Bert!! make it happen!
    im assuming you gave up on the 13% reduction? personally i wouldnt have..
    but thats me...and if this other boat works for you--awesome!
    you have my support always..
    Doug
     

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  14. BertKu
    Joined: May 2009
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    Location: South Africa Little Brak River

    BertKu Senior Member

    Thanks Doug. Yes, I gave up on reducing any plan. When one gets older (I am now 72) than times seems no longer to have 18 hours per day, but a few hours at the most. I am not planning to go through a divorce like so many others who are working day and night and lend up in misery.

    When I was young, I build an electric string base, made a colour TV from scratch, wounding deflection coils etc, build furniture , made a double story house, and lots of other items, but today, I will be pleased if I get my boat within 4 months in the water after 3 years struggling with the software and printed circuit boards and all the metal works.

    Before I attempt to add any crazy contraption, I will first test the boat out with low power electric propulsion and get the feel for "drag". Thanks for your suggestion, I will later tackle it again. How is your tugboat coming on?
    Bert
     

  15. tugboat

    tugboat Previous Member

    Hi Bert- Its slow--i also gave upon my own design - it probably could have worked but I didnt want to invest time and money in uncertainty--even though life is always a risk..however i found a design i like better--I am still going to use steam as a propulsion but a small diesel will work till the steam engine is installed.

    what you can do is make a test model of your boat using 3/4": 1' builders scale-
    (18mm- ?)

    It has taken me two years to finally get my engine, shaft, stuffing box-props, etc..and bought plans from glen-l. also had to buy a good welder-learn to weld- buy two other welders to see which one is better, spend money on making models, shipping, and many othe rthings..just to get to the building stage.but its all good because now its not going to take long-- maybe two more years.. to quote Mal Low-N.A. "its a Long road for the backyard boatbuilder"!
    hang in there Bert-- never let go of your dreams and turn them into goals...!! then reality- I always say- "build it in you mind before you build it in life.."
    hope you enjoy the pic pf my soon to be beautiful boat-

    steel is being bought in december---and all this after i made the frames for my other one which i also abandoned....
    keep me posted...
     

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