DIY Simple Catamaran Sailboat Design

Discussion in 'Boat Design' started by WilliamPrince, Oct 10, 2013.

  1. bpw
    Joined: May 2012
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    bpw Senior Member

    Do you have the hardener to go with that resin?
     
  2. WilliamPrince
    Joined: Oct 2013
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    WilliamPrince Junior Member

    No I do not, despite reading the West Systems building guide explaining each hardener and additive, I didn't trust myself enough to actually buy one, instead I decided to come back and ask for clarification. Which one do I need for which use? Based on what I have read I need 207 or 209 (it is very hot here in Baja, so it will cure faster,) as a hardener, and 406 to fill/make my joints. I'm not sure, but I think 407 additive would be a good finish coat, and could be sanded down to make a good adhesible (is that a word??) surface for a final coat of paint.

    Another option of the final coat, like others have been mentioning, is the possibility of the fiberglass application. I'm assuming that polyester resin is fiberglass resin... If not then I made a stupid purchase. Anyways, I will at least attempt to fiberglass the joints, if not the entire underside.

    The way I see it, I don't have the budget for marine plywood, so I have to make do with normal plywood, and protect it in any way possible. So how can I protect my plywood exactly?

    1. As much as possible, soak the plywood in some sealant. Does anybody know anything about this? CPES is the product I have easily available.
    2. Once the plywood is soaked, apply an outside layer of epoxy, probably resin + 207 or 209 + 407 = good outer layer?
    3. Could I fiberglass + resin outside of an epoxy layer? Would that be reduntant or would it not adhere? I don't fully understand the fiberglassing/resin process, all tips are appreciated.
    4. House paint. I think this will be a fantastic, relatively cheap, and good looking outer layer of protection.

    Thats like slipping 4 condoms on my boat, come on what can go wrong???
     
  3. Skyak
    Joined: Jul 2012
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    Skyak Senior Member

    I have not seen a good decked 16ft double ender lately. Bolgers sweet pea is pretty close in form. I know a way to make a good bottom fast and then scribe the topsides and deck.

    For now check this for size.

    http://www.flickr.com/photos/hallman/tags/sweetpea/

    Your idea that you are ready to build....

    You have two containers of resin and no hardener. 5200 is high quality caulk.

    Do you have a list of provisions and equipment? cruise guide? Passport? budget?
     
  4. WilliamPrince
    Joined: Oct 2013
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    Location: Mexico

    WilliamPrince Junior Member

    When I state that I am ready to build I don't mean I have learned everything and have everything necessary to build; I designed as I learned to design, and in the same way I will learn to build as I build. Of course I have no lumber, and no hardener, and I am missing much in the way of knowledge, but these things will come (the first two are much easier than the last.)

    To give you an idea of how stupid I was when I started this, take a look at the second most recent post of this blog: jameswilliamprince.blogspot.com That's right, my original idea was to build a log raft. I think I have made some enormous leaps and bounds in the right directions.

    Provisions are not a problem, I am an experienced camper and backpacker, and will be taking similar foods on board as I would backpacking. Dry food, canned goods, power bars, trail mix, pemmican, etc.

    As for equipment, I have a lot of good camping gear, which isn't entirely applicable on the water in some cases... But I will collect a few more pieces of gear before I leave. That time will come as well.
     
  5. WilliamPrince
    Joined: Oct 2013
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    WilliamPrince Junior Member

    This just in: I now understand the resin/hardner relationship, as well as thickeners and additives. I will update my inventory tomorrow, well perhaps today.
     
  6. upchurchmr
    Joined: Feb 2011
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    upchurchmr Senior Member

    If you are going to use epoxy don't mess around with other cute options.
    There is no need to soak plywood in anything else. Once you cut the panel shapes, paint the endgrain and any splits/ knots with epoxy. Make your joints. When you have the hull shape, smooth off any excess so the fiberglass lays evenly and doesn't snag. Drape the cloth over the hull, wet out with epoxy - brush or roller.
    Once the resin sets, fill the cloth with another coat, repeat until it sis smooth. Don't stop for the day until the weave is filled, cause if you get a waxy surface when it cures, you can easily wash it off. If you get wax on unfilled cloth, you will have to sand off some of the cloth to get the wax off. Nothing sticks to the wax.

    Fast of slow hardner depends upon the temperature. At 100 degree f you don't want fast except for a 5 minute job (a little exaggeration, but not much) You are much better off with slow hardner unless it is below 70 degrees. Especially when you are learning to use epoxy.

    Sanded epoxy is the best surface for painting, the only reason to try another filler is if you have large areas to sand smooth (fairing the surface).

    If you are going to use epoxy at all then use it for the fiberglass also. Polyester is much weaker although much cheaper. Epoxy protects the plywood from water, if you follow the west system guide (glass with epoxy and 2 more fill coats) you will have a coating that waterproofs and protests from abrasion damage. Paint is required to prevent the epoxy from degrading in the sun.

    If you just use epoxy and glass for making the joints, you will still have a good boat, expecially if you keep up the paint and avoid driving the boat onto the shore. I would be shocked if you don't get 5 years with this method, and possibly much longer.

    1. Dont soak the plywood. just seal the edges, cracks and knots with epoxy
    2. Epoxy by itself will protect from water, if it is thick. It is not strong for protection from abrasion on the shore.
    3. Two common methods for epoxy fiberglass.
    Coat with epoxy, cure, then lay fiberglass and wet it out.
    Lay the glass on uncoated wood, then wet out the glass. As long as you sealed end grain and cracks you will have a great strength bond.
    4. House paint works, but if you are going to be in the water all the time it might not be as good. Others have suggestions here.

    Good luck.
    PS - Return the polyester resin in my opinion.



     
  7. peterAustralia
    Joined: Mar 2006
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    peterAustralia Senior Member

    hi william,

    you are getting there,
    since you have bought epoxy, yes you can use that in place of polyester resin to reinforce your fiberglass. Epoxy is better as it is very waterproof, but it costs more.

    CPES - clear penetrating epoxy sealer - this is used to make wood more durable. Not as good as coating the outside of the wood with epoxy, but it can make wood last longer. Generally wood will take longer to rot away than plywood. CPES is pretty ok, since you have bought epoxy resin, I would go with that. (epoxy resin)

    What sort of boat to build?
    That is your business
    I am biased - tacking outrigger is my website.
    Having sailed multihulls and monos, i prefer multis.

    A multi will tend to go faster, handle waves a bit better, be more stable, be unsinkable. Downside is that they can carry less weight, often dont have a cabin. In the end its up to you

    These are the boats I like

    E17 outrigger canoe
    Outrigger 16
    Flaquita
    Roonio
    Hawk 16ft cat
    Slider catamaran

    http://www.tacking-outrigger.com/e17.html - maybe build yours a little shorter and fatter, so it is easier to make and can carry more gear.
    http://www.tacking-outrigger.com/outrigger16.html - copy this in plywood
    http://www.flaquita.net/
    http://www.duckworksbbs.com/plans/jg/roonio/index.htm
    http://www.duckworksbbs.com/plans/sf/dayboats/cats/hawk/index.htm
    http://www.duckworksmagazine.com/09/designs/slider/index.htm

    Because your on a budget, and running out of time fast, you wont be able to make a really really good boat. Something simple and easy is about all you can do. If you are desperate for on money and time, you can do this
    http://www.tacking-outrigger.com/madagascar.html

    I think central america with long distances, shallow water, reefs, generally less wind, makes a multihull more suited than a monohull. Thats just my opinion.

    Me, I would copy this
    http://www.tacking-outrigger.com/e17.html

    In the end its up to you
    Your 6 weeks is now down to 5 weeks - not much time to build your boat

    other posts on how to use epoxy seem pretty accurate
    assume you need a slow hardener because of the heat
    Slow hardener for hot conditions, fast hardener for cold conditions
     
  8. Skyak
    Joined: Jul 2012
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    Skyak Senior Member

    I have been searching for free 16ft double-ender plans and struck out. 'Pea-pods' are the common name of this style hull in an open craft and 'surf' or 'rescue' boats have the same shape but not the sail. I could quick draw a flat bottom version but I wanted some shape for better heavy loading. You still don't seem to know what you need to carry so I it all seems pointless.

    The one free design I would suggest you take a look at is

    http://www.jemwatercraft.com/proddetail.php?prod=DKTour

    an 18ft X 35" one chine canoe. Hard deck the first 3 ft and soft deck back another 4 to a soft dodger and a full tent. This canoe could stand up to a small sail or be used with an outrigger and bigger sail.

    The wax that appears on cured epoxy is 'amine blush'. IT WILL SCREW UP ADHESION. It should be cleaned off with acetone and the surface sanded before the next layer. Builders use plastic 'peal ply' to avoid this work.
     
  9. upchurchmr
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    upchurchmr Senior Member

    Skyak,

    If you are going to act like an expert on info from another thread, at least get it right.

    Amine Blush is cleaned off with water. You certainly don't need acetone. You don't need to sand, but you might go ahead if you feel like it. If you sand and the paper clogs up fast then you did not wash good enough.
     
  10. bpw
    Joined: May 2012
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    bpw Senior Member

    West coast is deep water territory, no reefs. Light air is true in southern mexico, but Sea of Cortez gets some good breeze in the winter and Gulf of Teahutepec hits 50 knots on a regular basis. Can be very squally in some areas.

    If you screw up and flip a multihull next stop is the Marquesas.

    Multi-hull should be considered, but not sure it is the right boat for a complete novice, bit less forgiving of mistakes. Personally I would love to do a Sea of Cortez trip on some fast beach cat.

    It also means you need to build two hulls, almost twice as much work.

    I think the west coast of Mexico and Central America is a pretty lousy place for beach cruising all in all, few harbors, big swell. Sea of Cortez is a different matter though, I have not been into the sea personally, but lots of people kayak and sail small boats around in there.
     
  11. WilliamPrince
    Joined: Oct 2013
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    WilliamPrince Junior Member

    Okay, let me change the odds a little bit. The original challenge I set for myself was to make it across the Sea of Cortez. I added on the part about Costa Rica, but as a novice sailor, a novice boatbuilder, and a naive young lad, I think my chances are slim. So lets go back to my original goal: just to get across the sea to Mexico. Anything else is extra.

    As for what I am taking with me Sky, I actually know very well. I will be taking the majority of my belongings in a small waterproof semi-inflateable backpack, this includes a few articles of clothing, as well as assorted travel gear like a hygiene bag, my passport, my wallet, a first aid kit, etc. This includes all my survival gear like compass and energy fudge and 2L water. This will weigh about 20lbs.

    Then I have my camping gear:
    - Sleeping bag
    - Small one-man tent
    - Inflateable pad.

    Then I have food, which will consist of
    - 20 cans of beans and chili
    - 2 pounds of dried mashed potatoes
    - 10 cans tuna and chicken
    - Assorted fruits (oranges and apples mostly) and vegetables
    - 66 tortillas (so precise.. Wow he must be really prepared)
    - 2 gallon ziplock bags of trail mix.
    - 1 jar peanut butter
    - 1 gallon granola
    - Snickers bars
    - Beef jerky
    - Dried fruit
    - 20L of water (thats heavy, could be ballast?)

    And heres the kicker... I will be bringing my bicycle, in order to continue my bicycle trip on the other side. Is that stupid? Will it rust in a matter of days? I can cover it with something as some protection from the elements, and I can break it down into 2 wheels and a frame for easier transport... So there you have it, that's all I'm taking.

    Based on this, and based on all you know so far about my skill level in such matters, which is better.. A monohull, outrigger canoe type thing like Flaquita, or a cat like Slider. I will start building as soon as I find a place to build, which will be by next Tuesday at the latest. Peter, I think you underestimate how fast I will be able to build this, although maybe that is because I overestimate how fast I will be able to build this. I think I could have the whole thing done in 3-4 weeks. Anyways, we shall see.

    Also Sky that free design is GREAT, really. As a basis for whatever I end up building it is a very interesting guide.
     
    Last edited: Oct 17, 2013
  12. El_Guero

    El_Guero Previous Member

    Mexico?

    You have to take 10 pounds of hot peppers!

    Toilet paper .... soap ....

    Take mostly flour tortillas, corn don't do so well without heat.

    You need more water, you have food for about 12 to 15 days, but barely enough water for 4 to 5 days.

    Maps.

    Emergency location beacon.

    Radio.

    PFD.

    Sea anchor.

    Anchor?

    Rope.

    Flashlight.

    Mirror.

    Jacket.

    What else?
     
  13. SamSam
    Joined: Feb 2005
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    SamSam Senior Member

    If something happens, a lack of water will kill you much quicker than a lack of food.

    You need a life preserver and some sort of life raft float-able thing unless your boat is unsinkable.

    Communication of some sort would be handy, a radio, flares, an epirb or something. A signal mirror maybe.

    A compass, a fishing line and hooks.

    Depending on the boat and winds, it could only take a few days to cross. Of course, you could also be adrift for months.
     
  14. peterAustralia
    Joined: Mar 2006
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    peterAustralia Senior Member

    hey william

    5 weeks is not long, if you have a helper and have built a boat b4, then i would say fine. time is going to be a real killer here.

    a monohull is difficult to find a place to store a bike. a cat has a platform where it can be stowed, taking extra water will do no harm. when i go bushwalking the compass never leaves my neck, the compass is really important!!! laminate your maps with that clear book covering film that you get from the supermarket, its very cheap. an epirb is nice - i have one - but they are expensive - me i would take the chance and go without.

    radio - hmm, hand held vhf - i have one - only have a range of about 4km, i would not bother. pdf yes. flashlight yes, i would take 30L water, the extra water gives peace of mind. u have a cooker of some sort, i need my caffeine fix every day.

    anyway, have fun
     

  15. WilliamPrince
    Joined: Oct 2013
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    Location: Mexico

    WilliamPrince Junior Member

    Thanks everybody for the advice - all good things to think about. I am ready to start building, even if I'm not ready to complete the task alone.. But as for now I don't really have many more questions, apart from the monohull vs multihull debate. As I have a feeling this debate could go on for a long time, with no obvious right/wrong answer, I won't wait for it.

    I will update the thread again when I begin building, or somebody supplies an interesting new perspective. Thanks a ton for all the help.
     
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