Large sharpie for the Adriatic

Discussion in 'Sailboats' started by Igor, Jul 1, 2022.

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  1. rnlock
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    rnlock Senior Member

    Buoyancy high up will help, even if the lower parts of the boat aren't flooded. It won't look like a traditional sharpie, though.

    I think, from context, I understand approximately what AVS means, but I'm curious what the original words starting in A, V and S are. Many absurd possibilities come to mind, but none that relate to the apparent meaning. At one point, I was taught some hydrostatics, but I can't remember that particular TLA.

    I wonder if a horizontal foil on the skeg would keep a Wharram or other boat from hobby-horsing as much? I also wonder if other Wharram designs hobby-horse as much as the Tiki does. This doesn't mean I necessarily think a particular Wharram is suitable or unsuitable.

    I've finished two plywood small* boat projects and designed and built another. Compared to the rest of the building, the sheathing wasn't much work. For plywood, I think you only really need enough glass to keep it sealed. Which isn't much unless it's an area that gets a lot of abuse. So I think we're probably talking only one layer. For those who really hate fiberglass and epoxy, there's MDO, aka medium density overlay, which I understand is like sheathing. If I'm not mistaken, it's covered with phenolic saturated paper. Often used for outdoor signs. I don't know if this is available in Europe, and seams would still have to be sealed, sheathed, whatever.

    I imagine a strip planked, sheathed boat would require much more glass/epoxy, since it isn't very stiff or strong across the grain. Either that, or a lot of framing, and even in that case I wonder if it wouldn't work enough to damage thin glass.

    *Very small. I could pick up any of them. The sheathing holds up to the weather very well, for many years, if it's not mechanically damaged. Then, if the boat is kept outside, there's a problem. Some of the surfaces were covered with 0.75 ounce (or was it 0.55 oz?) cloth. I guess that's about 23 gsm, light enough to be trickier than heavier cloth, but still no big deal.
     
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  2. rnlock
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    rnlock Senior Member

    Is a mooring any more dangerous than a dock, which has a lot more traffic? There are people who love to post video compilations of stupidity with boats, but I don't know if I've seen even one that included an incident at a mooring. Plenty at docks, though. Ditto in real life, though the number of incidents I've seen in person is much lower. If there are shallow areas, and Igor ends up with a shoal draft boat, he may be able to moor in some place where most large boats can't go. I admit that won't stop idiots on jetskis* or in small boats. I've seen boats moored in places that were dry when the tide was low.

    *I hope those aren't as much of a universal plague as I think they are. (Revenge fantasies deleted.) Speaking of fantasies, I've been imagining a Folding Schooner, decked over, with a ballasted keel that could be hoisted for shallower draft. That's about as much of a cruiser as I could afford.
     
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  3. tane
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    tane Senior Member

    Angle of Vanishing Stability http://sailskills.co.uk/Stability/sailskills_stability_stability_explained_AVS.html
     
  4. rnlock
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    rnlock Senior Member

    Thanks! I guess that makes more sense than Angle of Getting much Wetter. That probably means something else anyway. It's even better than Anguished Vanity Shattered, though that probably happens too. ;-)
     
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  5. Rumars
    Joined: Mar 2013
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    Rumars Senior Member

    The economics of building are very much location dependent. For example a Tiki 26 is mainly 6mm okoume with 200g/sqm (6oz) glass. Local (and I mean same urban area I live in) prices are ply 43€/sqm, fiberglass 5€/sqm, glass tape 1€/m, epoxy (mixed) 11€/kg. One square meter of skin glassed only one side costs 49€ without epoxy. We need around 3-400g of epoxy for fillets, tape, glass and 2-3 coats of neat epoxy for the inside face, so let's say 4€. Total would be 53€, and yes I ignored the price of the filler.
    A similar size cat in strip would be 12mm wood with 450 biax each side (generous scantlings). Wood 10€/sqm (pine, saw waste included), glass 5.5€/sqm and epoxy the same 11€/kg. That's 21€/sqm without epoxy, and we need 1kg for the glass and another 0.5kg for glueing and impregnating the wood, let's make it 18€. That's 39€/sqm, and 14€ less per sqm, but a stripper needs a strongback, so the actual saving is less.
    I can actually get both ply and wood to a lower price if I'm willing to travel during business hours, and it would probably end costing the same amount.
    In my example builder preferences are probably more important than savings, but that is only because of location. Ply is expensive to ship, while epoxy is not, simply because of the volume they occupy. But in the grand picture it's rare that sheated ply comes out ahead of strip with local wood.
     
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  6. tane
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    tane Senior Member

    & not to forget: even on a small boat the material for the naked hull (wood, glass, epoxi) will at the very most be 40% or so of the total, so 10% or 15% savings on glass & wood will not amount to all that much. Everything else being equal the round bilge boatwill sell faster & at a better price than the chine one. (I know, at this point in time nobody thinks of selling, but still...)
    btw I would be loath to use pine for a stripplank/glass/epoxi hull, just to save money over western red cedar
    check out the ply prices here, Rumars; BRUYNZEEL HECHTHOUT | garantiemultiplex Okoumé prijslijst https://www.af.nl/voorraad/plaat/multiplex-garantie-okoume/prijslijst.htm - Bruynzeel too!
     
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  7. rnlock
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    rnlock Senior Member

    Seems like you're comparing very light ply with strip wood that would be much heavier, since it's twice as thick. I think the ply could be cheaper (and more rot resistant) and still end up with a lighter boat. I really don't think 6 oz. cloth is necessary in areas that won't be abused. Certainly not on the interior walls and overhead, and probably not in some of the areas outside.
     
  8. Rumars
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    Rumars Senior Member

    Yes, I agree, the savings in material are not significant in the overall picture of a bigger boat. I was just trying to explain that strip, while consuming more epoxy is not more expensive then sheated ply and that can make a difference in some areas.

    I know the published prices, Arnhem 29.20 + 6.13 (21%VAT)= 35.33€/sqm vs. S&T Hydro 34.75€ (19% VAT included). Driving time probably matters more in this case.

    Using spruce/pine/fir instead of WRC is a matter of beliefs if sheathed both sides. I don't think WRC is worth the price just for beeing rot resistant, after all balsa cored hulls are doing just fine with the proper care. If lightness is mandatory Abachi or Paulownia are (or at least were) cheaper, if not I would use fir. I only see WRC as a logical choice with traditional stripping techniques wich are not sheathed both sides and must use a light wood. Otherwise we have plenty of black locust (robinia) available but in recent times the (local, might be different elsewhere) price has climbed up there to iroko and other less known tropical hardwoods.

    Yes, in my example the stripper weight would be a little more then double the ply, since my pine is about the same density as okoume ply. That can of course be rectified with some money (we can get a stripper to the same weight no problem), but the question is if it's necessary. If it's a raceboat then yes, by all means, but for a cruiser?
    As for rot resistance no, okoume is not more durable then pine, and less then WRC.
     
  9. Igor
    Joined: Jul 2022
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    Igor Junior Member

    Jet ski's are a common nuisance here. We call them idiot-wagen. Luckily the laws are quite strict and planing is prohibited closer than 300 meters from the shore, they seem to stick to it as they are mostly rented and if they go out of the permitted area the renter kills the engine via remote control.

    The problem with the mooring is that I still have to find out is it allowed. All boats Here are kept in the marinas, I have the marina berth but it is not large enough to accomodate multihull.
     
  10. Igor
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    Igor Junior Member

    I was a bit intimidated by strip planking (bead&cove) as time consuming job but then I got plans for strip planked surfski and outrigger canoe and it can be done much more easily than I previously thought, everything is done by little steps so big mistakes are less likely to happen. Resulting hull have much better hydrodinamic properties too.

    There is discrepancy between strip planked and chined boat plans as former are usually much more substantial yachts, even in 6-9 meter range, with standing rigging, deep fin or bulb keels and in many cases with inboard diesel saildrives.

    It is a big departure (advance) from humble sharpie type, what I was really eager to find do those bold statements of stability and seaworthiness hold truth in places other than North Carolina shallows. I have never seen a sharpie, let alone sailed one. By sharpie I mean 30ft or so internally ballasted shallow draft boat with flat bottom and unstayed cat ketch rig, not lightweight skiff.
     
  11. rnlock
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    rnlock Senior Member

    I should have been clearer. I meant ply that was NOT okuome, and would therefore be somewhat cheaper. I have recently heard of paulownia plywood that someone in Europe was using. If that's cheaper than okuome, it might be a good choice, though it's so light it might have to be slightly thicker. I haven't seen it in the US yet. We have primed paulownia clapboards here, but they're kind of thin for sawing up into strips and one would have to get rid of the paint. We have meranti, at least at the supplier I've been looking at, that's significantly cheaper than okuome.

    A boat should be built at the displacement it's designed for.
     
  12. Igor
    Joined: Jul 2022
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    Igor Junior Member

    Here is Tiki 26 sailing under full sail in Croatia in Bora wind, boat speeds up to 15 knots. Speaking from the experience these gusts were in 30-40 mph neighbourhood. Not bad at all.
     
  13. Rumars
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    Rumars Senior Member

    Strip planking is only time consuming if you wish it to be. You can also have it in quick if you wish. Pay attention to the pictures on this blog, Construction strip planking du Mahi-Mahi 2, cata open de 9×6m, modèle : One Off: Le strip planking ou mise en place des lattes de bois sur les profils de couples http://one-off-design.blogspot.com/2016/04/le-strip-planking-enfin.html 29.02 you see naked frames, 4.03 he has just a few short strips to install. This is a dry planking method, the strips are trapezoidal and the thickened epoxy is all troweled on in one go. He has also chosen to build over permanent plywood frames, the strongback is minimal.

    As for strip boats beeing more substantial, that's because they are different designs. From a displacement point of view the 36ft Egret at her 7500lbs is not much different from Balta's Lydia at 3.4t.

    Brewer also has an interesting sharpies, one for ply, Ted Brewer Yacht Design https://www.tedbrewer.com/sail_wood/mystic.htm and a bigger one for foam/wood core. Ted Brewer Yacht Design https://www.tedbrewer.com/sail_glass/egret.htm
     
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  14. tane
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    tane Senior Member


  15. tane
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    tane Senior Member

    the set of the jib & the sag of the forestay - hard to look at. & they are sailing really close to a weather shore. 2 miles further downwind...
    (you can see the single biggest feature we really regretted that I hadn`t changed on our Wharram: the companionways facing the center! Spray from the windward bow flies directly there. So each time you exit or enter - whoosh, you get somewater down below. On passages with a lot of upwind sailing in stronger winds (Red Sea,...) we hated it. It would have cost the same in material & labour to have them facing backwards...)
     
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