Sea Going Triloboat Motor Sailor 48'x12'

Discussion in 'Boat Design' started by charlesakeem, Aug 31, 2016.

  1. charlesakeem
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    charlesakeem Junior Member


    What I'm needing is an extreme low-cost, quick to build motorsailor capable of crossing the Atlantic on occasion, dealing with the canals and seas of Europe and being a comfortable home when I reach various destinations. With a main design parameter being shoal draft and able to carry enough fuel for a potential circumnavigation. My goal is to cut my teeth with some Caribbean cruising, load up on plenty of cheap diesel fuel in Venezuela and then spend long periods cruising to distant ports before coming back to Venezuela to refuel. From plans I'm seeing the 48'x12' having a max displacement of 39,750 lbs at the max draft of 1' 6".

    So from my desire's, I'm looking to build a motor sailing trawler version of a Triloboat.
    I'm planning on it being 48'x 8-12'. It's intended usage will be mostly sailing/motoring around the Caribbean with a foreseen voyage across the Atlantic to check out the various canals and waterways of Europe.
    I'm looking at a Junk rig for easy self building and maintenance as well as a 3-71 to 6-71 Detroit diesel as the engine (low cost , reliability, ease of maintenance and parts).
    If budget and fantasy coalesce into reality there might be a copper sheathed hull in the works, like the designer has done to his boat.

    What I'm thinking now is to use 12' Southern long leaf yellow pine/ Douglas Fir 2x 4's or 8-12's going across for the hull bottom, with a thin sacrificial skin of ply over it. With skins and deck of AC ply with 4x4 framing.

    What are your thoughts of the plan?
    Anything to add?
    Would it be Seaworthy to make an Atlantic crossing under favourable conditions?

    I've checked other mentions of barges and Triloboats on the thread including an interesting/Amusing and quite long thread about a gentleman building something based on Noah's Ark. My thoughts now are to buy a project trawler, keep her afloat for a season or two and use the parts to build the barge. Nothing I see really has the fuel capacity I'm looking for.
  2. upchurchmr
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    upchurchmr Senior Member

    I'm not an ocean sailor, but I can't imagine getting caught offshore with something that will be pounded by the waves like that.

    Sacrificial skin? Sounds like an invitation to leak then sink.
  3. kapnD
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    kapnD Senior Member

    Not even.
    Not even close.
    Spend some time in the library!
  4. MikeJohns
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    MikeJohns Senior Member

    No, that is a semi sheltered water craft type that should not proceed offshore.
  5. rasorinc
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    rasorinc Senior Member

    A 48' boat can cross oceans but look at the hull of a sail boat. Look at a hull of an ocean
    going fishing boat or tug. You cannot design such a craft W/O years of education.
    Get to a library and start your education or higher an experienced NA now who designs such boats. How about telling us your home location
    and your boating experience, and age.
  6. charlesakeem
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    charlesakeem Junior Member


    [​IMG]Thank-you everyone for taking the time to reply and for looking over my post. I don't have considerable experience but am willing to learn and listen.
    I've spent considerable time in libraries reading on subject. (Last book read was Slocum's liberdade) if I could I'd adore a lengthened version of badger.
    My current home location is Southern , Colorado.
    But I'm usually based on Florida or Trinidad and Tobago.
    I'm 26 and the previous boat I've owned was an O' day 28.
    Now I'm understanding the barge hull shape is by far not the best . v-hulls and deep , full keels seeming to be preferred. What I was thinking was that this would be closer to something like Bolger's advanced Sharpies , or a Dory type hull. Designing something from the ground up would be beyond my skills , that's why I was using the Triloboat plans. Just adding considerable beef to the design. The designer and a few others seem to have been enjoying their boats in Alaskan waters which I don't think is the mid Atlantic but I would put above flat water lake cruising.
    What would happen to the design?
    Is it the bow, the shallow draft, lack of freeboard , Windows to big?
    What exactly makes a seagoing barge?
    Is this suitable for Caribbean cruising if not an Atlantic crossing?
    The sacrificial skin is in case of Marine borers that prevail in warm water and for the occasional rough grounding or coral reef impact. Something that can be chewed on/up if need be without compromising the integrity of the hull.
    Thoughts are along the lines of seagoing scow
    Last edited: Aug 31, 2016
  7. fredrosse
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    fredrosse USACE Steam

    Too Big for Hard Groundings

    "The sacrificial skin is in case of Marine borers that prevail in warm water and for the occasional rough grounding or coral reef impact. Something that can be chewed on/up if need be without compromising the integrity of the hull.
    Thoughts are along the lines of seagoing scow"

    Such a heavy craft would not easily survive "the occasional rough grounding or coral reef impact" . 40,000 pounds of boat coming hard against something as stiff as a coral reef will put a hole in just about any hull. Watertight bulkheads might save the day, but a tough design challenge.
  8. charlesakeem
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    charlesakeem Junior Member

    On bulkheads and floatation.

    Thank you for that, hmmm wondering what I could do to make an impact survivable to the hull. Copper hull sheathing (enormously expensive unless I melt pennies) A box keel perhaps? (Starting to wander into the dangerous waters of design).
    What I was thinking of in the fashion of Chinese junks was some order of compartmentalization. Thinking a collision bulkhead in the front section of the bow as well as a bulkhead by the engine room in the back to keep out the noise of that screaming Jimmy as well as provide water tightness. Possibly another in the form of a cabin, trying to think of other places as well. Was thinking the bulkheads could be AC ply over even plank bedded into fillets of Glass matt and epoxy all around,with additional framing lumber tying the entire structure together. Was also calculating how much airspace I would need to keep the vessel afloat if flooded. Figured I could rely a bit on my tankage once I start doing some journeying. Dead air boxes under the mattress etc.
  9. gonzo
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    gonzo Senior Member

    Chinese junks have a watertight bulkhead forward. The space between the bow and the bulkhead is open on the bottom for water to go in and out and act as a pitching damper. At least the traditional ones had.
  10. mydauphin
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    mydauphin Senior Member

    You need a keel, an ocean boat needs to able to self-right. This thing could island hop at best. I would rather have a 30 foot sailboat. Don't think comfort, think storm survival.
  11. sharpii2
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    sharpii2 Senior Member

    Rather than just telling you no, I will attempt to tell you why not.

    First off. You want to use this as a power boat.

    Its expansive flat bottom (and but what I've seen, I mean dead flat for most of the hull length) will slap and pound in any kind of sea way. The reason is the high initial stability which will always want to conform to the surface of the sea. This will create a huge twisting moment, especially as the full width bow tries to cram every wave or wavelet it encounters under it. The boat may be able to take it for a while, but after hundreds of hours of this punishment, vital parts are likely to work loose.

    The Bolger box boats may have flat bottoms too, but this is where the similarity ends. Other than having pointed bows, or very narrow bow transoms, they generally have a quite pronounced rocker, where most of the bottom is flat only from side to side.

    Even more telling, they are all sailboats.

    Sail propulsion comes with the consequence of heeling.

    When a 'flat' bottom boat heels, due to wind pressure on the sails, its 'flat' bottom becomes a "V" bottom, as the leeward (down wind) bottom and side corner (chine) immerse more than the rest of the bottom.

    The "V" they form tends to part the waves and wavelets they encounter, rather than trying to cram them down.

    For this to happen, you want enough initial stability, but not too much. With too much initial stability, not much of a "V" is formed and more cramming than parting happens.

    If you look at some of the seagoing flat bottom boats real carefully, you will notice they tend to have deep sections.

    The purpose of these deep sections is two fold:

    1.) to limit initial stability, and
    2.) to increase the range of stability.

    'Initial' stability is a measure of how quickly the boat can self right from a very small angle of heel, say 10 degrees or less.

    Too much of this is what you don't want when you want your chine to present a nice "V" to the sea. Flat bottom seagoing powerboats, such as dories, have very narrow flat bottoms and wide flaring sides, where the width of the bottom is only about half of the boat's Beam, for this reason. They also have this sectional shape so they will have a longer roll period, along with a greater range of stability.

    The 'range' of stability is the degree the boat can be heeled and still be able to come back upright on its own.

    The deeper sections allow ballast to be stowed lower in the Hull. Such also usually means higher sides in relation to the boat's width (Beam). So, when the Hull heels, the side to side (transverse) Center of Buoyancy (CB) not only moves to the lee side, but also moves up towards the deck somewhat, so there is a distance between that and the boat's Center of Gravity (CG). As long as this is the case, and the CB is leeward of the CG, the boat will self right. When the opposite is true, you're going swimming.

    The Hull type you are considering, due to its enormous initial stability, is less likely to be capsized than it is to be bashed to pieces from below and above by rough seas.

    Long before that, you may be rendered too sea-sick to do much, as the violent, snap rolls of the boat cause you to toss your cookies.
    bajansailor and Ilan Voyager like this.
  12. charlesakeem
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    charlesakeem Junior Member

    Thank you all.
    Gonzo don't believe I'd recalled that about Chinese Junks, very interesting I was mostly speaking on simply compartmentalization.
    Mydauphin, was thinking of comfort but mostly of fuel capacity, while there are various sailboat hulls I could convert into a terminal trawler, perhaps even a terminal motor sailor with junk rigs.
    I couldn't think of one that would have the shallow draft and fuel capacity necessary for the Caribbean and the European canal system. If Mydauphin or anyone else has some idea's concerning this I'd be extremely glad to hear them.
    Sharpii2 thankyou, that's exactly the type of information I was looking for and you have given me much to think about. Depending on the design, Triloboats either have 3/4 to 1/3 of there design completely flat. The 3/4 design having an abrupt knuckle but also has the ability to more gracefully swoop up at bow and stern. Included the drawing of the different bowshapes and the link to article, if you have time to peruse.
    Was planning on it being a Motorsailor but I don't think the rig and hull form really would have me heeled over much at all, nor do I necessarily know how it would motor drastically heeled. Have heard the blunt bow helps the boat rise over the waves vs necessarily going into and parting them.
    I this article is a pic of the bottom of Loose Moose II
    Trying to find the pics of the more rockered hull shape.
    Even with all the framing, possibly with even more reinforcements and a well picked window to make the crossings. Do you think it will still pound apart in a sea?
    What if window was chosen to reduce waves, even if it's at the cost of motoring most of the way.
  13. mydauphin
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    mydauphin Senior Member

    Checkout this guy. He is building an ocean capable boat. . He has videos on YouTube also. This will show what an amateur can do but show you that a ship is more than a boat to cross the ocean.
  14. charlesakeem
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    charlesakeem Junior Member

    Thank you Mydauphin. I was linked to him only about a week ago surprisingly, have been watching his Propeller casting video's. Pure beauty and genius, things like that are why I have links to backyard foundrist and David Gingery's works in my tag.
    Wondering about the modification of having a fine bow though that seems like a massive design departure. So far I've heard at least one endorsement for having it be an island hopper. Which reasonably speaking. A life cruising the Caribbean and South and Central American shore doesn't seem too unpleasant.

  15. messabout
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    messabout Senior Member

    Well done reply Sharpii2. OP please take note of the not so immediately obvious considerations of boat versus sea state.
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