Improving the design of a Hartley TS21

Discussion in 'Sailboats' started by jumbuck, Mar 14, 2011.

  1. Petros
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    Petros Senior Member

    two CBs would get you closer to what you want, more complicated and heavy I would guess. I am a big fan of dagger boards, they are simpler, they are lighter (they do not weaken the hull since the slot is much smaller), they are more efficient (less drag w/o the long slot). If it were me I would use two light dagger boards with a shallow draft weighted center keel.

    It is hard to believe you got no differences in performance. Could be that some of the configurations were not as optimum as they could have been, a poorly executed design will not perform well no matter its merits. It would be hard to draw any conclusions unless they were all equal and each configuration was optimized, there are just too many unknowns. Sometimes small changes in certain details can make a big difference in performance.

    All of the fixed bilge keelers, with a center keel option, done by the same designer, always perform poorly compared to the center keel version.
     
  2. terry hagan
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    terry hagan Junior Member

    so you think 2 lifting cb's hidden behind the seating would be the best option' i did think of dagger board's but when i beach her i ill have them protruding up into the cabin and that is what i'm trying to keep clear. the more i think about it if the 2 cb's come out trough the bottom of the hull TROUGH a small keel, which would also be the legs to keep hull upright would that be ok
     
  3. PAR
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    PAR Yacht Designer/Builder

    Terry, it would be best if you define your needs as precisely as you can, so you don't wish for something that you'll curse owning after building. Bilge keels have only one real advantage, the ability of the boat to take to ground, bolt upright. So if you live in a high tidal range zone, plan on running aground or beaching a lot, then bilge keels make a wise option. Of course, performance will be degraded to some degree with bilge keels, if sailing along side another, stock Hartley, it'll be noticeable, but other wise, probably not so much.

    Stubby bilge keels with center or daggerboards, will permit shoaler draft, but you'll still have the performance disadvantages, plus the complication of two cases, extra weight, two retractable appendages, two sets of hoisting gear, etc. A better option would be to forget about the stubby bilge keels and just use twin boards (whichever). Lastly, on a boat of this size, a daggerboard will likely get snapped right off in a hard grounding, which is something to recommend centerboards (pivoting boards, in each bilge). Daggers work well on small craft, but quickly become a dainty burden on larger. Multihulls are the exception (because of weight and loading) in this regard, but that's not what you have. The performance difference (pivoting, compared to dagger)will be negotiable, again, unless sailing next to a stock Hartley, but the advantage of a pivoting board to bounce along with no damage is impressive.

    In the end you'll have to decide what's most important to your sailing needs, not our respective opinions on various appendage configurations.
     
  4. terry hagan
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    terry hagan Junior Member

    yep. thank's Par.......well i won't be starting the build till end of this year so lot's of time to think. i'm from UK now living on the western side of Central Luzon, Philippines. lots of lovely beach's mostly very gentle slop, tide range in spring tide is just over 1 meter in neap is less than a meter. So you think 2 pivoting board's each side enclosed in the seat's maybe the best option, i know it will mean 2 lots of lifting gear, which, i'm sure with some thought could be removed when having meals, but it will mean the cabin is very open, i'm 90kg and moving around and having to negotiate the cb casing could be a pain haha.
     
  5. terry hagan
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    terry hagan Junior Member

    the 2 pivoting c/b's would come out of the hull, not trough stub keels, in the area very close to the first chine.......this is what i'm thinking in reply to what u advise....
     
  6. PAR
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    PAR Yacht Designer/Builder

    I don't think you need bilge keels, stubs with boards or just bilge boards in a tidal range like that. Your in shoal country, but with gentle drop offs, not much of a worry. What is the fixation on bilge keels/boards, etc.?

    I have several designs that use a stub keel, to lower the impact the centerboard case has on the cabin spaces. In fact, several have zero impact, being all under the sole and in the stub keel. This could be done on your boat, with half the effort and equipment of a twin setup. The Hartley 21 plans are offered with a fix keel, centerboard or if you ask, bilge keels (my understanding anyway), so the options are covered.
     
  7. capt. mannering
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    capt. mannering New Member

    all you need i 2 poles to tie to each side if you want boat to sit upright on the sand lad. you are building in the tropics so coat wood in epoxy. i find if you thin down ht9000 or west system with preimium unleaded petrol it soaks in much better. the petrol evaporates out and then the epoxy sets. i have heard acetone is good to. i think a canting keel could work for you if want performance and ability to take the ground. the power pack can run a genny as well as hydraulics. also you can use cheap ply and standard nails, the epoxy stops corrosion. hope this helps, bless you and your family.
     
  8. Gary Baigent
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    Gary Baigent Senior Member

    If you're determined to have two keels/boards why not go the whole way a la Terrorist - and that is asymmetric dagger boards at the turn in each bilge, angled slightly outwards, angle of attack of 3-4 degrees, the leeward one stays down, windward up when you sail - AND that way you'll have the ability to sit the boat level in shallow water because both can be withdrawn to same height... plus having a boat that will beat any other boat your size (and many above) while beating to windward.
     
  9. terry hagan
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    terry hagan Junior Member

    hi guy's
    been busy the last few weeks so not able to come to the forum.
    I've also been looking at a design from UK, ''Blue Storm'' by Kieth Callaghan, lovely boat and an interesting build. i sent him an email about 2 cb's and he was happy to alter the design for me, but cost is the thing. anyway i'll stay with TS21 and try and get some measurements of 2 main bulkheads and see if 2 cb's would work so if anyone has the Sheer height and 1/2 width, Both Cine heights and 1/2 widths,, w/l height and 1/2 width that would be a great help...has anyone ever used an electric motor in a ts21 i'm also looking at that idea..
     

  10. terry hagan
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    terry hagan Junior Member

    yep. that's what i'm looking at Gary 2 cb's controlled by lines from the cockpit....will they need to be weighted/balested...or just ply
     
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