New design for a very old type of boat

Discussion in 'Boat Design' started by David L. Dodd II, Jun 28, 2020.

  1. David L. Dodd II
    Joined: Jun 2020
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    Location: New York

    David L. Dodd II Junior Member

    Many many years ago, in a sea far far away, fisherman used small double ended schooners called pinkies (The Eastern Seaboard of North America). These boats could be heavy full ended carriers or fast models with deadrise, hollow entries, and long fine runs. These vessels where tremendously weatherly, could stand up to almost any storm, beat off a lee shore, and work in any condition. They were the epitomy of practical design. The pinky sterns had tombstone transoms that resembled the back of a fishing dory. The tombstone naturally became a boom crotch. The transverse supports for the pinky stern became traveller rails, and a place to sit. Every part of the design fulfilled a purpose or several purposes with the ease that comes from a design that is created not by naval architects in rooms far from the sea, but by sailors and fisherman who needs a ship to keep them alive.

    To create this not so modern take on the classic pinky, I have studied the lines of many different pinkies. Some where extremely full ended, others very sharp with high hard bilges and much deadrise. I used moderate deadrise amidships, medium slack bilges well below the waterline, a slighly hollow entrance and a slightly hollow run in order to maximize speed while still leaving plenty of room for accomodations. The forward stations have no hollow in the garboard, and the after stations only slight hollow. She is full on deck and sharp on the bottom. The ends of the ship are well balanced. She has some old fashioned features, including catheads, knightheads, and trailboards, though the winch shown would likely be electric and attached to batteries beneath the deck. The deckhouses could easily have solar panels on their roofs, though these are not shown.

    Since this is a yacht, not a fishing vessels, the area normally reserved for the catch could be repurposed for accomodations. I added fore and aft deckhouses in the interest of head room, but kept them low, just above the bulkwark in order to keep from spoiling the look of the boat or her sailing qualities. Since I used deck houses, I eliminated the small raised fore deck that was used for accomodation in the working pinkies.

    This design omits certain details for clarity: chainplates for the stays, details of the rigging of the netting below the bowsprit, and the knees that support the bulkwark and gunwales. In addition, the masts shown are not to scale and actually just place holders. Actually masting diameters have not yet been worked out.

    This model was made in Delftship free and this program does not allow asymmetric layers so the interior layout and the sail plan must be designed in another program.

    She is about 50 feet over all (not counting the bowsprit), and draws 5 feet with a 12 foot beam. This makes her an oversize load that is trailerable without an escort on most roads in the US. She displaces about 23 long tons. Delft series resitance calculations suggest she needs between 5 and 70 kilowatts to cuise from 6-9 knots. Her maximum speed in a blow, carrying too much sail would be about 11 knots, producing an amazing 5500 lbs of resistance. Bowling along like this, she would most certainly have a b0ne in her teeth. On the other end of the spectrum, once she starts to move she will have plenty of inertia, and will be able to ghost along at one to three knots in even the lightest breeze.

    Please enjoy and comment as you desire.

    David
     

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  2. TANSL
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    TANSL Senior Member

    Welcome to the forum, David. Beautiful hull and very good work.
     
    Last edited: Jun 29, 2020
  3. DCockey
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    DCockey Senior Member

    Nice work. Did you find pinky lines anywhere other than in Chapelle's books?
     
  4. David L. Dodd II
    Joined: Jun 2020
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    David L. Dodd II Junior Member

    Dear David Cockey,

    Yes and no. I found lines from other sources, but upon tracing them back, found they all came from drawings or redrawings originally created by, found by or republished by Chappelle. He has his name on a huge amount of American sailing history. The breadth and depth of the lines he saved for history cannot in any way be looked at as anything other than amazing. His prolific work has been criticized by some for its lack of rigor in regards to the theory, but the sheer volume of work has a quality all its own. Even if the origin stories told aren't perfectly accurate, and even if his theories not completely sound, the lines that would otherwise have perished speak for themselves with such vivid beauty that any criticism seems like a mosquito bite. Irritaing but eventually meaningless.

    In the end, I cannot think of better day spent ashore, than one in the library surrounded by books written by Beken, Biddlecombe, Bray, Chapman, Chappelle, Cunliffe, Fox, and Macgregor.
     
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  5. Rumars
    Joined: Mar 2013
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    Rumars Senior Member

    Nice boat from a bygone era. Do you plan a traditional plank on frame build?
    That deep forefoot will make her heave to wonderfully under bare poles, for the price of high skin friction and lower maneuverability in tight quarters. Light air performance will see you using all the traditional gear like bonnets, ringtails, flying jibs, etc. Modern marinas might prove a challange without a bow thruster (asuming single engine).
     
  6. David L. Dodd II
    Joined: Jun 2020
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    David L. Dodd II Junior Member

    I am planing the build in a barn not far from Lake Ontario. The barn is currently unused, since the owners have retired from farming. I have a huge space with no obstructions and a very flat floor. I plan to build a mold on strong backs and make a foam sandwich core grp hull. I plan to use cement ballast and batteries to bring her down to her lines. The farm has some old tree trunks that have been seasoning for years and would make great masts. The tractors that the farmer still has are great at providing power for block and tackle, and in the past he has used block and tackle in the barn to raise heavy objects. The last time I built an inverted hull (much smaller) I used eliptical frames built around the hull to flip it. With the help of the tractor and the blocks and tackle this should be pretty easy. To keep weight down during flipping and transport, the ballast can be added when the boat is in the water and before fitting out. The fore and aft cabins will not be installed until after launching so that ballast can be shipped through the large holes. The barn also has an access door for a semi truck. A marina with a launching cradle large enough to handle this boat is only four miles away. The marina offers mooring bouys. Using a slip with the long bowsprit is probably not ideal. I do not intend to put a motor in her since prop drag would spoil her sailing qualities. I am tossing around the idea of a tender with an electric motor to push her around or tow her when needed. The tender would have its own batteries, or the ability to hook up to the schooner's much more poweful batteries. Electric motors provide better low end torque than gas engines, so the tender should be able to push the schooner around if formed right. The tender will need a much larger screw than normal, and a broad flat transom to avoid squating.

    Heaving to was a feature of extreme importance in the type, since they fished exposed waters. The ability to carry sail and beat to windward were also important since the best fishing was off a lee shore. The type does tend to be hard to stop, once moving, since 23 long tons has a lot of inertia. As far as light air performance goes, it isn't actually that bad. Big heavy double enders like this tend to keep going once they start, and the schooner rig with a jib on the bowsprit, baldheaded fore mast, top sail main mast and a fisherman staysail provides a lot of sail area for the boat length. These boats traditionally had deep reefs, and with such large sail plans, they needed them. In addition, we mast schooners differently in the US than in Germany. Our schooners have more sail area on the mainmast. Since we place the mainmast at the mid point. Most old world schooners put the mainmast farther aft. I am including a picture of a Ted Brewer Sail Plan in order to illustrate the difference. The American rig is a veritable wall of canvas. It is interetsing to note some of the differences between my design and Brewers, I have higher bulwarks, lower cabins, and a different sheer sheer line that is flatter forward , but more cocked up aft. I absolutely love Brewer's fine little vessel. I suspect that his exagerated sheer actually makes the vessel look better in 3d due to subtle optical illusions that happen in broad beamed vessels. I know for a fact that Brewer's design is a great sailor, and I hope mine is as well.

    I am inlcuding the Delft ship and Winters Drag calculations for the boat. The Winters calculations are for small canoe type boats and most likely less accurate than the delft series calculations. Low end resistance is actually not terrible due to the slightly hollow waterlines and easy curves. She pays for this later with increased wave resistance.
     

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  7. clmanges
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    clmanges Senior Member

    I like it! The first words that came to my mind were 'stately' and 'graceful'. I also thought 'heavy' and 'imposing', but that might just be a reaction to the color scheme.

    The Brewer sailplan looks awfully complex (though I don't really know how to discern what I'm seeing). Would it take a lot of crew to operate it? Just curious, since I gather you have a different rig in mind.
     
  8. David L. Dodd II
    Joined: Jun 2020
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    David L. Dodd II Junior Member

    I am planning a very similar rig. Most of what appears to be complexity is actually mechanical advantage. Those sheets you see along side the sails are lazy jacks that help gather the sail. The many parts of the sheets on the gaffs provide mechanical advantage trading length of rope for ease of raising and control of the gaffs. With modern winches, and electric power, the rig is even easier to handle. This type of rig can be handed by two people when cruising, though three would better if trying to maneuver in tight quarters. In fact, that is the plan.

    The color scheme is extremely conventional. The bottle green was almost ubiqitous in that day in age. So was the rust colored lower section and black bulkwarks. A yellow waist line was sometimes also seen. If you are interested in more details the gaff rig handbook by John Leather is a great resource.

    I have found an online reference for you here. The Gaff Rig Pages - Gaff Rig Overview https://www.frankhagan.com/weekender/gaffover.htm The page is old and hasn't been updated much, but then again, so has the gaff rig so all should be well.
     
    Last edited: Jun 29, 2020
  9. Rumars
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    Rumars Senior Member

    I asked about the wood construction since you have some features that will be difficult with fiberglass. I am thinking of the proeminent stem/keel/sternpost wich makes no real sense on a foam core boat. I understand they are important to you esthetically so I propose that for building you redesign them as separate external laminations in wood epoxy and fair the transition to the glass skin with thickened epoxy. If you plan inside ballast I would use foam core only above the waterline and go solid GRP beneath. The boat is big and heavy enough to not be bothered by it even if you use solid fiberglass for the whole build. Might also be cheaper that way.

    I know why the deep forefoot was used, and while correct for the original vessel use, your use differs, it is a yacht not a fishing boat. It not only increases wetted area, it also adds significant amounts of buoyancy wich must be ballasted down. Since you are not sailing around with tons of fish in the holds this must be compensated with ballast. You can even see it historically, the boats used to carrying people and not freight get their forefoots trimmed down and their keels start to point up (pilot cutters, early yachts, etc.). Ted Brewers boat also has less forefoot and more rake in the stem and stern (no surprise here, he is famous for his "Brewer bite" after all). I suspect that the rake is also responsible for his deeper sheer.
    You have chosen a very american sailplan indeed. I would have envisioned topsails on both masts and a flying jib. It always comes down to designing for the prevailing wind conditions, the rest is just patience and if necessary "creative light air sails".
     
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  10. David L. Dodd II
    Joined: Jun 2020
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    David L. Dodd II Junior Member

    Thanks so much for the responses. I really loved reading your comments.

    Excellent point about the keel. I am kicking around two ideas for that. First, and the one I am thinking I will not use, The Keel and trailboards could be made with marine plywood sheathed in fiber glass cloth and the rest of the hull faired in as you say. Instead, I actually want to cut the keel from double thick foam glued with staggered seams, sanding the edges round to make it easier to glass. I want to attach the foam core for the sides onto the keel with a thin layer of epoxy so that they have an open butt like on stitch and glue boats, and then use some expanding 2 part closed cell polyurethane foam along the keel hull junction to fill in the open butt. Then I will bend the the foam around the plug and fix it to the deck stringers. In the last hull I built, I used thickened epoxy in a similar way, but I think the expanding foam may work better. Finally the expanding foam can be sanded to a fair curve to allow easy glassing. I am planning to build a three foot model and test my building plans to make sure everything works. If the 2 part foam doesn't work well on the model, I will probably use a third method and make foam wedges glued into the keel hull juction with epoxy and sanded fair.

    My last hull was only about twenty feet long, but was light and performed well until a fire destroyed it several winters ago. It had an outside keel as well. I wanted to avoid the thickened epoxy, because I had problems with slumping and shrinkage. The shrinkage pulled some of the hull out of fair. It was all repairable, but took longer. The area near the keel was dished in a little bit. It glassed over fine but aways bothered me. I ended up glueing a sheet of foam to the unfair area and sanding it down fair with the rest of the hull. I did not need internal balast on the last hull, since it had a lot less displacement. Thinking about it, the foam core construction could be a problem with internal ballast. I like it because it is easy and fast, even if it is a little expensive. I can get the foam pretty cheap but shipping is a killer. I am not sure exactly how I would make the grp hull fair without the foam. I have never built a straight grp hull before, only a cored hull. Pehaps the cored hull would still work if I used extra glass matt in the areas where the ballast will go.

    I liked the construction technique because it was very fast, gave me an excellent hull shape, and was well within my capabilities as far as simple to work materials. It was highly toxic and required me to use a face mask, so that is a downside. Based on the previous hull, I expect to be able to complete this build four months after I start. I have built one other boat many years ago out of wood. That experience convinces me that I would not have enough time to make a wooden boat of this size by myself. It would probably take years. This boat would be about eight times the volume of my wooden boat and about four times the volume of my previous foam core boat. If I had a team of skilled woodworkers willing to work for free, this would be a sweet wooden boat build. Cold moulded plywood is the only other option. I have never tried that. I do have Reuel Parkers Book on it though and it is intrigueing.

    Thanks so much for your comments.

    David
     
  11. Rumars
    Joined: Mar 2013
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    Rumars Senior Member

    You would build a solid glass hull the same way as a cored one. The only difference is that instead of planking the mold with foam, you plank with wood. Either thin cheap plywood over stringers (as you would with foam sheets) or skip the ply and strip plank the mold. Stripping is without any glue, just fix the 1x1 or 1x2 battens (of the cheapest wood you find) to the frames (screws, nails, staples) without big gaps. Then fair the wood with a heavy grit and staple plastic sheets over the mold. Now you are ready to laminate as usual, only much thicker. Some stabilize the wood with a layer of CSM and use fairing putty to get a nice inner surface, some infuse the hull instead of hand laminating, and there are also methods like C-flex where the plug surface is incorporated into the hull.
    Wood epoxy construction can be similarly fast if the proper methods are used.

    While a push tender is feasable I would simply use a diesel with offset shaft and a folding or feathering propeller. Added resistance is minimal and you don't need to cut a big hole in the rudder or deadwood. If you want to go the extra mile, twin props with electric motors and a big diesel generator. More expense, more weight, but better weight distribution and superior maneuverability.
     
  12. clmanges
    Joined: Jul 2008
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    clmanges Senior Member

    Thank you for the explanation and the link. I took a very--very brief interest in sailing before deciding it wasn't for me; still, it's fascinating, and I enjoy learning about a lot of things, even if I know I'll never use the knowledge in practice. It helps to keep my old brain from rusting.
     
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  13. Dejay
    Joined: Mar 2018
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    Dejay Senior Newbie

    Beautiful boat and interesting read! Similar clmanges I don't want to sail but intriguing nonetheless.

    Do you plan any solar panels?
     
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