Block Island Cowhorn

Discussion in 'Boat Design' started by goodwilltoall, Jan 16, 2014.

  1. goodwilltoall
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    goodwilltoall Senior Member

    Put this down on paper a few months ago after thinking about a boat that would present an actual full vee to the water (at rest). Have the old "roaring bessie" article and recent woodenboat magazine for "scrimshaw" which is kind of a rehash of the first. From what the owner says they can be fast with a great motion.

    Used chine rather than bent frames as I can more easily figure and think it would be quicker to build if the panels can be twisted to form. Overall I wanted reduced displacement so at the midship its about 3" less beam at WL but the rest of the stations I drew are the same as original at WL. A little less draft where as the original has rake that continues to stern this keel levels off. Different rig and lead ballast rather than stones. The interior is very small because of shape so raised the freeboard amidship to allow standing headroom throughout, would have went with a deckhouse but the raised deck was the only way to get seperate berths.

    This is very preliminary and had enjoyment sketching it but probably will not pursue it much further.

    Peace.
     

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  2. Sailor Alan
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    Sailor Alan Senior Member

    Block Island Boat

    First congratulations on an excellent reproduction of the Block Island boat in hard chine form. Though tender at first, it will stiffen up nicely as it heals, rather like a heavily loaded dory, which it resembles hydrodynamicaly. I am reminded of George Beuhler work, and of course, Bolgers 12.5.

    I would strongly suggest removing the forward most port light, and replacing it with a clear deck light, or even a deck prism. These latter are quite effective. I would also suggest smaller ports, but i am biased, having had a port burst in, in a seaway. The strictly vertical sides might look a bit “tumble-home” but that is not so bad.
    I would also extend the two settees forward, there is nothing so annoying as not being able to ‘lounge’ properly on a settee when its raining and miserable outside.
    I have had very bad personal experiences in the north pacific (Swiftsure Bank area) with using accommodation in the ‘eyes’ of a similar sized boat. The vertical displacement in the confused seas was far too much for staying seated, even with hand holds. Just something to consider. We crew had the use the ‘skippers’ facilities in the stern quarters, much to their annoyance.

    I also suggest most strongly two masts. You have to experience the utility of a second mast to appreciate it, a mizen is amazing. You can spread far more effective area at lower CP using two masts too. My personal preference for this boat would be two similar sized aluminum flagpoles. The forward one I would attach to a hot dipped galvanized (and/or powder coated) steel fitting (welded 1/2” steel?) on the forward bulkhead, projecting some inches above the deck, and spreading the mast load across the bulkhead, and into the deck, and keel/forefoot. The 'flat' on this fitting would accept the 4 bolt base of the flagpole, holding the flagpole at a suitable rake angle, perhaps 10' from vertical.
    This boat is not light, so I would place a similar flagpole, using a similar fitting, about 14/15' forward from the stern post. This fitting would tie to a permanent support pole, also possibly galvanized (and/or powder coated) rather than a bulkhead. make sure this mast has slightly more rake, perhaps 2-3' so they "look" parallel. I could draw these fitting for you if you like.

    The rig would be classic Block island, with short 'clubs' (18-24" long) at the heads, and loose footed booms 14' long at the foot. The sails would be similar, if not identical. The masts would be as tapered as possible, perhaps 10" at the base, 40' long, and 2" at the top. You might like to use a double purchase halyard to reduce longitudinal strain on the masts. The 'club' should use a "Parrel Bead" protected loop of halyard around the mast to hold its foot against the (variable) mast section both at the top, and whilst reefed.
    I prefer to mount the loose footed booms to a short stub just aft, and part of, the mast step proper. This tightens the foot as the sail is sheeted home, but most importantly, does not induce lateral loads into the free standing mast. Hollow aluminum does not like point loads. In the same way, i would lace the sail to the mast, no track at all, such that this lacing line tightens as the sail is hoisted home.
    Note, this line can be independently tightened after reefing as well.
    Reefing is simply a matter of releasing the halyard, hauling home the new ‘clew’, usually pre-roved, (we require a boom mounted winch for this) then tying in the new ‘tack’. The loose foot can be tied up at your (relative) leisure. I prefer cringles, and tiers.
    The loose foot is of great benefit. It allows great sail shape trimming for high and low wind velocities, even with a less than perfect sail cut. It also allows painless tacking, and much lower strain on the foresail sheet. It reduces the need for winches, hopefully to none. I personally like a huge roach on the foot, and one can get away with it running because of the raked mast.

    I would carry a mizen? (main?) staysail of light nylon, to fly between the masts in less than 5kt apparent wind. Some would advocate a similar sail flown from the foremast on a temporary bowsprit (just a plank lashed to the stem-head and anchor windless) about 4’ long. I am ambivalent. The staysail would need to be dropped to tack or gybe, but should not be flown in a short tacking situation anyway.

    Do not worry too much about CP/CLR lead, the long keel eases this issue, and the two masts with separately trimmed sails makes it irrelevant. I would increase the chord of the lower rudder, perhaps making the trailing edge vertical. The lower half of the rudder does most of the work, aeration etc robs the upper rudder of effectiveness, but the two masts will make steering, and self steering a breeze.

    Congratulations on a brilliant (conceptual) design. I hope it gets built.
     
  3. rwatson
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    rwatson Senior Member

    My reaction is that its a poor imitation of the real thing.

    For a start, why isnt the rudder heel lower than the forefoot, like on the real design ?
    http://www.georgebuehler.com/Block Islander.html

    The is a reason for that on the original - when beating up, up a restricted passage, you can go right up to the edge of a channel , and when the rudder heel touches, you can go about easily. On yours, you will have to wait for the tide to come in. Overall maneuvering ability will be badly affected too by the 'flat' keel.

    I think you have managed to really 'uglyfy' the topsides considerably. Wait till you do a render of that flat cabin top and minimal sheerline.

    Onto the practical issues - a sketch in an exercise book doesnt account for weight distribution and therefore trim given the displacements. Your section designs are just 'wishfull thinking', and may not even be developable.

    You need to get a lot more worked out yet.

    As to the original design, I agree with the published assessment

    "By today's ideas this hull is totally obsolete. It's to beamy and symmetric, it has way to much wetted area, to deep of a forefoot,"


    With a beam over 10% of its total length, its a real slow boat.

    There are dozens of designs that will perform much better, with more interior room.

    But, by all means reproduce a 'classic' design for nostalgia sake, but making an inferior copy just doesn't make any sense to me.
     
  4. redreuben
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    redreuben redreuben

    Wow, brutally frank.
     
  5. Mr Efficiency
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    Mr Efficiency Senior Member

    Mixed reviews, I'd say !
     
  6. pdwiley
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    pdwiley Senior Member

    Well, it's pretty simple to get the full lines & offsets, rig and interior accommodation plans for a 45' (I think) Pinky schooner that's been built and known to work. Chine hull, too.

    Dirt cheap plans cost is a bonus.

    PDW
     
  7. Sailor Alan
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    Sailor Alan Senior Member

    A bit harsh, it is just a conceptual sketch after all. I hope you miss spoke about having the rudder hit first, even in mud this is dangerous. Just like Buehlers design, the bottom of the rudder should be parallel to the WL, but some inches (4-6”) above the rear heel of the keel proper. If the rudder heal hits first, even in mud, you are likely to tear the rudder off the lower pintail, and that is a pain to repair. It is after all what a lead line, or marked boat hook handle is for.
    I agree, more drag to the keel would be desirable, but this is hardly a fully faired shape yet. It certainly isn't ‘weighed’, and ‘balanced’.

    I disagree with your comments about the stations. They probably would not ‘fair’ as is, but ill bet they could be made to follow simple conical sections, especially if the chine line is allowed to run down and ‘follow’ the shear line. I might even raise the chine line forward, to smooth flow transition.
    I think the original deck camber is a bit excessive, but it is a direct product of the shear line and beam chosen.
    I would definatly suggest a slight reduction in overall beam, perhaps to 12’, but no less. I raced a 39’ French production boat with a 13’ beam, and it was a very successful design too. Definatly a product of its rating rules (RORC), but then again most boats of that era in Europe were that tubby.
    I agree there are many designs that might perform better, many of George Beuhler’s designs fall into that category, but none of his are speedsters either.
    Technically, the propeller aperture should be in the stern post, not the rudder, and the rudder needs to be bigger per my earlier suggestions. I might even consider tiller steering, especially if i went with the twin raked masts.

    In the cabin, i would lower the floor a few inches, just to give a slightly better feeling of space. There is certainly room between the couches. Then the pilot berths are quite generous in width, they can be narrowed as the beam comes in. Perhaps the answer here is to scale the sections as given, keeping the side elevation much the same and adding the keel drag, and rudder modifications.

    I can see this with some refinement and the twin mast Bahama sloop rig being a very successful heavy displacement, comfortable, and probably fairly cheap cruising boat, for northern or southern waters.
     
  8. frank smith
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    frank smith Senior Member

  9. rwatson
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    rwatson Senior Member

    Harsh ? Please don't take it as a personal comment. I assure you I am truly only concerned with the design in its own right.

    Sure. its conceptual, but you asked for comments - on its major features, and if a parallel, full length keel isnt a major concept, I don't know what is.


    Slightly - I said 'rudder heel', probably could have been expressed as the bottom of the stempost. Like all good designs, the rudder is shorter than the stern so it cant hit first. Ideally, the deadwood on the keel should extend past the bottom of the rudder to form the bottom pintle for total protection, - with the strategy that you explained in detail later. You got the gist of the idea OK, I think.

    I notice you didn't comment on my point about reduced maneuverability .



    I bet they don't, and I have the 3d software to prove it. When you get around to the waterlines, I will happily run you off a rough rendering to prove it.

    Success in what area ?

    Not speed, efficiency in volume, Cheaper ? I don't know why it would be any cheaper than another boat, more maneuverable ?, not with the first keel line as shown.

    As a design, I cant see any virtues of interest. But keep trying by all means. I am happy to analyze any concepts you come up with.
     
  10. rwatson
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    rwatson Senior Member

    I cant think of what the similarities to a graceful, well balanced design with a purposeful keel line you see. edit - sorry, I phrased that badly, it does have the flat undersections like the original concept, of course

    Its a better illustration than I could find of the ideal rudder/keel line setup, thanks for that
     

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  11. PAR
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    PAR Yacht Designer/Builder

    What is the logic of basing a new design on an antique, that's well established as a bit of a pig, unless of course you plan on taking on gale force winds regularly?

    You can have the look of a pinky, cowhorn or whatever, yet unincorporate all the bad attributes, while keeping the aesthetics values you desire.

    Attached is a construction profile of a recent design I've done. Above the waterline she's a gaffer, right out of the late 19th century. Below she retains her manners at sea, yet has had a considerable amount of wetted area removed, divided appendages of reasonable section, external ballast, etc., etc., etc. so she'll easily outperform her similar counter part, yet unless standing next to the travel lift when she's splashed, you's never know, unless you happen to be sailing along side and can't figure out why she's out pointing you, has crisper maneuverability, is more easily propelled (power or sail) and has less materials in her, which you have to buy, shape and install.
     

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  12. frank smith
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    frank smith Senior Member

    How about a Schonker!

    schonker.jpg
     
  13. frank smith
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    frank smith Senior Member

    Is this cool, or what !

    PieriusMagnus10.jpg

    PieriusMagnus11.jpg
     
  14. PAR
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    PAR Yacht Designer/Builder

    I hope displacement speed isn't a big goal and lastly, why would you need windows at each side of the topsail?
     

  15. Rurudyne
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    Rurudyne Senior Member

    Displacement slow?
     
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