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Thread: Small Shallow Draught Self-Righting Sailer

  1. #36
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    Default Re: Small Shallow Draught Self-Righting Sailer

    In addition to sea-worthiness, you have to also consider sea-kindliness. If the boat survives, but batters you to a dying pulp in the process ... look for a copy of Danny Greene's Cruising Sailboat Kinetics.
    Await dreams, loves, life; | There is always tomorrow. | Until there is not.

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  2. #37
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    Default Re: Small Shallow Draught Self-Righting Sailer

    htom - not familiar with that one. Will look for it. Thanks!
    David G
    Harbor Woodworks
    http://www.harborwoodworking.com/boat.html

    "It was a Sunday morning and Goddard gave thanks that there were still places where one could worship in temples not made by human hands." -- L. F. Herreshoff (The Compleat Cruiser)

  3. #38
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Quote Originally Posted by Ian McColgin View Post
    ... I do not see value to water ballast in this design brief since a boat beamy enough to really use such ballast while sailing will be a pig to row and not that much fun to sail unless designed for that sort of racing and not for highly versitile cruising. ...
    Water ballast is not part of this design brief, nor is rowing. This brief is "Small Shallow Draught Self-Righting Sailer".

    I personally do have a preference for water ballast though but that is merely because I have been using it to satisfaction for many years now, just as I had been using fixed ballast before that. Water ballast can do all that lead ballast can do, while lead ballast cannot do all water ballast can. The specific advantage of water ballast is that it can be used as "Ballast-on-Demand".: Water ballast can be taken in when needed, and be shed when not needed. On the open sea.
    Water ballast in, the boat becomes a sturdy "uncapsizeable" displacer, water ballast out, the same boat can be planed, and can be rowed quite unlike a "pig".

    Anyway, water ballast yes or no is not part of this particular design brief, so please carry on mentioning also small fixed ballast boats which can be taken out far off shore.

  4. #39
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    Default Re: Small Shallow Draught Self-Righting Sailer

    To my mind a boat like john welsford swaggie is the best small cruiser. seawothy and protective of the crew.
    the crew are away the weak point my skipper used to remind me.
    James

  5. #40
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Small yachts from Paul Fisher: http://www.selway-fisher.com/Yacht2024.htm

  6. #41
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    Default Re: Small Shallow Draught Self-Righting Sailer

    I am sorry that I'd gotten confused as we learned more about the design brief as it went along. For example, the notion of voyaging was not at all obvious in the OP.

    I added the reference to the WBM article on LFH's Carpenter and her successor.

    But I am still at a loss as to what's really wanted here. There are a few hundred excellent ocean cruisers in the size range though in the fixed keel versions the draft desider of 2' is hard to make, 3' being more common, while for a centerboarder of this size 2' board up seems awefully deep.

    No boat is uncapsizable and no boat has zero inverted stability. But there are many boats that take wind and sea quite well and of these many that will in practice come up from complete inversion because the sea conditions that knocked them over will far more readily put them where a positive righting moment from say 140 degrees can take hold.

    These need not be ballasted boats. It would be fun to see what actually happens if you could knock down an LFH Meadow Lark, something that I don't think has happened. Especially if she had watertight hollow spars, as designed, and maybe even a mast float, the power of buoyancy would put her upright even if you managed to roll her in a very large breaking sea.

    The biggest risk is not so much the design - it's been done in many ways - but the construction and the attention to interior layout. The chaos of a knockdown anywhere near much less past ninty degrees is hard to imagine. Everything, especially yourself, falling all over. Any flaws in hatches and ventilation quickly revealed. Weaknesses of deck structure laid bare. Take a simple item - batteries. Were they installed and strapped down such that they are not going anywhere when the boat's upside down. And that ballasted fin or swing keel that can go up and down. When you're upsidedown, what keeps if from crashing through the overhead? Even simple stuff like floorboards. As you go over, what did you do to keep them from becoming airborn slicing slabs.

    All of these things are solvable and there are several excellent texts on the topic of preparing an ocean-going yacht.

    One excellent point of the dream as outlined: The size of boat will not oppose the sea. She may need to lie to in the worst gales where a larger and crewed boat could slog on, but she is small enough that the stress of sea and wind will be much reduced and she'll have more strength per pound, be less likely to suffer hull breach or rigging failure, than larger boats. A worthy goal.

  7. #42
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    Default Re: Small Shallow Draught Self-Righting Sailer

    When we bought a Laser stratos keel another sailor bought a 29er.

    The ultimate lightness of the 29er made it just a smidge faster on flat water, but in waves the extra weight of the Stratos was overcome by a much bigger gennaker.

    On rough water the weight and confidence of the Stratos made it faster, the 29er was over a lot. He described his 29er as a lake boat the stratos as a sea boat.

    What was noticeable was a moments inattention could have him in on the 29er, whereas the stratos's bulb gave an extra 2-3 seconds of time to release a sheet or get some order before things went too far. We never had it over.

    Also we found the extra keel stability improved windward performance as the boat more easily stayed upright. It pointed unbelievable high.

    In light air when a boat is jigging around in a leftover sea, the bulb at the bottom of the dagger board could move around in a separate fashion from the boat a bit in the case. So how a weighted board is held needs careful thought. Also it mean't a small crane and tackle was needed to lift it over the case to raise it. No big deal but it was a two man boat to deal with that and helm coming back to shore.

    Dad asked Keith Callaghan to design a one man version with a weighted 70kg centreboard and Genny which is the Haze 4000.

    http://www.bluelightning.co.uk/Haze/haze01.shtm
    Last edited by keyhavenpotterer; 01-30-2014 at 05:24 PM.

  8. #43
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Ian's comments are pretty much on the mark.
    My boat is an LFH Meadowlark, so I need to add to his comments on that.
    The meadowlark is a heavily ballasted modified sharpie, about 45% ballast. As such she is stiff and weatherly. Whimbrel has a water-tight cockpit. If I were knocked down, I would take little if any water below. I have worked to windward in winds gusting over 40 knots. The divided sailplan is a big part of that, but in truth the Leeboards are better for this than some other ways of reducing leeway. Another element of this is the light displacement, which let's a small sailplan drive the boat at a good speed. For Whimbrel to go offshore there are a few small jobs to complete.....securing floorboards and such as Ian spoke of. Ultimately Whimbrel could lie to a sea anchor in survival conditions. With nothing to speak of below the water, she would face the wind and sea easily under the circumstances.
    According to my calculations, the Meadowlark assuming a watertight envelope should self right from a knock-down to about 135 degrees without considering the buoyancy of the masts.

    Re the design brief... I'd have to say a ballasted modified sharpie may be the only choice.

  9. #44
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    Default Re: Small Shallow Draught Self-Righting Sailer

    As Phil Bolger was looking over my boat, his Triple Keel Sloop for a Dry Out Mooring, he asked me "How long does it take to self right when you get knocked down?". Fortunately I was unable to tell him. Evidently she was designed to self-right. 22ft in length and 18"draft. But requires a special "cradle" trailer.
    "If a man speaks at sea where no woman can hear, is he still wrong?"

  10. #45
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Quote Originally Posted by Ian McColgin View Post
    The chaos of a knockdown anywhere near much less past ninty degrees is hard to imagine.
    I'm sure many of you have seen it before, but if not then the crash test boat videos are well worth watching. Chaos is certainly the word.

    I supposed in the conditions where you might roll you're unlikely to have much or any canvas up, so no sails to slow recovery. Any idea how often rigs survive a roll? I suspect that smaller boats might be at an advantage there since they tend to be relatively stronger.

  11. #46
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Is there any use in the "roll bars" that some ocean rowing craft use? They seem to have enough volume to make inversion unstable. If designed aerodynamically, the windage could be reduced a bit. For hot-weather sailors it could double as support for a canopy, and for campers, a tent. It does interfere with a boom, unless the boom is already high by design, or unless the roll bar is part of the mast step arrangement. Two of them for main and mizzen....? -- Wade

  12. #47
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    Default Re: Small Shallow Draught Self-Righting Sailer

    With a low enough center of gravity and as much water-tight integrity as you can muster in a wooden boat (could be close to 100% if the right effort and materials are applied), then theoretically speaking, almost any boat could be made to be "self-righting". I would be looking for a boat with as much cabin and as little cockpit as possible and then during construction I would endeavor to mitigate as many points of ingress for water as possible. For example, I would adapt the design in question to have hatches that were as watertight, small in size, few in number, and as close to the centerline of the vessel as physically possible. (No sliding hatches on this little Dreadnought!)

    In consideration of construction materials I would mitigate as much weight aloft (not just in the rig but in the hull as well) in exchange for adding as much weight down low as possible. If you can save 100-lbs with a birds-mouth mast (totally out of the blue figure, no idea how much you could actually save, would depend on the mast, materials, etc.) then go ahead and add 100-lbs of lead ballast as low down as possible, even outside the hull on the keel if you can. Also, in the interests of being "self" righting, don't forget that any other weights inside the hull, ballast or otherwise, must be absolutely SECURED. If they shift in a roll and cause the center of gravity to settle below the metacentric height, in the newly inverted orientation, then the vessel will be more stable upside down than it would be right side up, and thus remain that way indefinitely.

    Watertight integrity and center of gravity. If you can master those two things then you will have conquered the concept of self-righting.
    "And all I ask is a tall ship and a star to steer her by..."

  13. #48
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Watertight integrity and center of gravity. If you can master those two things then you will have conquered the concept of self-righting.
    Yes and no. If some water squirts in around the hatch for a minute or less while the boat is inverted, it won't really matter other than that things get damp below. But having a high center of gravity when inverted doesn't guarantee recovery. There was a famous example many years ago in the single-handed round-the-world race when a boat that should not have been able to stay upside down did in fact do that -- for an extended period in rough conditions that the designer and builder believed would for certain bring it back up. This boat had a ballast bulb on the end of a long fin keel. But the beam of the boat and who knows what other factors kept it from coming around. There have been other examples of self-righting boats refusing to self right -- in some cases because the keel snaps off at some point either before or during the capsize. And then there was Jean-Pierre Dick who a year ago lost the ballast keel on his Vendee-Globe boat, but managed to complete the race without it. This stuff is not simple.
    -Dave

  14. #49
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Quote Originally Posted by Craic View Post
    Water ballast is not part of this design brief, nor is rowing. This brief is "Small Shallow Draught Self-Righting Sailer".
    Fair enough. This kind of boat is unsuited to my own mission, so I guess I have nothing in particular to add.

  15. #50
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Have we talked about bilge keels yet?

  16. #51
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Quote Originally Posted by capefox View Post
    Have we talked about bilge keels yet?
    Stu Fyfe has, in post #44, kind of. Thanks, Stu.

    Come to think about it, I would endorse the proposal for bilge keels -or triple keels- in this project, maybe in connection with some additional waterballast. I had an open triple keeler built in the seventies once and it was fast, comfy and very stable though drawing only 2 ft. Went surfing down big waves as if on tracks, over 10 knots. It had a good bit of leeway when tacking up in light winds, but that decreased when the winds and boat speed got up. Always safely tacking up from a leeshore, even under jib and mizzen alone. The open cockpit space was unbelievable, compared to any centreboarder of same size.

    Yep, a bilge-keeler could fit the bill here, or perhaps a longkeeler with waterballast in the keel bilge and leeboards. I will revisit the Phil Bolger collection at http://hallman.org/bolger/isometrics (Thanks, rgbarr!) for something suitable, PB thought a lot "outside the box" and his work is a big treasurechest for unconventional practical solutions.

    There were recommendations here to compromise on the full self-righting requirement or to altogether avoid open sea conditions in which the boat could be rolled.
    I disagree, this and any offshore sea-going boat (interior, ballast securing and rig) better be prepared from the outset and ad hoc to survive some rolling, whenever that might strike. Not seeking for that of course and not looking forward to it, but to be unafraid of it happening when it actually looms.
    Last edited by Craic; 02-01-2014 at 05:24 AM.

  17. #52
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    Default Re: Small Shallow Draught Self-Righting Sailer

    I will revisit the Phil Bolger collection
    how about #333
    Ragnar B.

  18. #53
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Ragnar,
    Phil Bolger #333 (Bilge Keel Yawl) looks very nice, and very stable, but from what I can see at wikipedia and at the hallman.org website, she is not a true PCB and also seems to have lifting bilge bulb keels, and I would not trust those, any even just slightly loose ballast keel or board banging or moving in the slot makes me uncomfortable. Besides, #333 is somewhat too big.

    I think I have made up my mind now: A single shallow, long, steel-keel yawl, with on-demand waterballast in the keel groove bilge, and with leeboards as per SBJ #25 ("Proposed Cruiser"). A Gunter Yawl rig, with a relatively short sturdy mainmast and a fairly long carbon gunter yard. As open boat, a longer "Jinni" simi-lookalike with turtle decks fore and aft.

    I will be looking specifically for such boats.
    Last edited by Craic; 02-01-2014 at 12:08 PM.

  19. #54
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Quote Originally Posted by Craic View Post
    "Self-Righting" meaning self-righting from any angle.

    "Shallow Draught" meaning 2 ft. max (with centerboard up).

    "Small" meaning 23 ft. hull length max, and lightweight enough to be trailerable.

    "Sailer" meaning capable of tacking up to upwind in a stiff breeze.

    Any such boat / plans available anywhere?

    Anyone interested in a new design?
    First we need to define "self righting".
    When self righting is talked about in a boat design it is usually to a certain number of degress.
    For instance some sailboats are self righting to 120.

    Now if that boat gets rolled in the ocean it will come back up but then it takes a certain amount of time.
    Also the mast and rigging can be broken and the rig can be tangled up and crew members can be injured or decapitated.

    Self righting is a kind of life saving kind of design for ultimate survival (YOU) out in the ocean.

    Then there is another level called "stability "
    Like how stable is the hull form BEFORE self righting becomes an issue.

    With a centerboard slamming up or down that needs to be considered because that can CHANGE the stability mid stream.

    I would want to know why you want this type of design?
    It is like there is missing information.

    It sounds like you want to build a sailing SCOW or racing SCOW.
    You might want to look that up.

    Why reinvent the wheel?
    I love the smell of fresh cut plywood in the morning.

  20. #55
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Quote Originally Posted by Craic View Post
    Ragnar,
    Phil Bolger #333 (Bilge Keel Yawl) looks very nice, and very stable, but from what I can see at wikipedia and at the hallman.org website, she is not a true PCB and also seems to have lifting bilge bulb keels, and I would not trust those, any even just slightly loose ballast keel or board banging or moving in the slot makes me uncomfortable. Besides, #333 is somewhat too big.

    I think I have made up my mind now: A single shallow, long, steel-keel yawl, with on-demand waterballast in the keel groove bilge, and with leeboards as per SBJ #25 ("Proposed Cruiser"). A Gunter Yawl rig, with a relatively short sturdy mainmast and a fairly long carbon gunter yard. As open boat, a longer "Jinni" simi-lookalike with turtle decks fore and aft.

    I will be looking specifically for such boats.
    "Turtle decks" ???????
    I love the smell of fresh cut plywood in the morning.

  21. #56
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    Default Re: Small Shallow Draught Self-Righting Sailer

    "On demand" water ballast"????

    It still takes time for water to go through a hole.

    Maybe you just need a submarine?


    Made up your mind in two posts? WOW.
    I love the smell of fresh cut plywood in the morning.

  22. #57
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Quote Originally Posted by mizzenman View Post
    how about #333
    Here is that design right?
    I love the smell of fresh cut plywood in the morning.

  23. #58
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    Default Re: Small Shallow Draught Self-Righting Sailer

    no.

    Google
    #333 23'6"x5'8"
    V12-N16
    Conceived and built by PCB's brother Wm. T. Bolger. Cat yawl, with ballast bulb bilge fins.
    and its the first one that comes up on images
    Ragnar B.

  24. #59
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Quote Originally Posted by mizzenman View Post
    no.

    Google

    and its the first one that comes up on images
    Ok ...I see that one now.
    I love the smell of fresh cut plywood in the morning.

  25. #60
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    Default Re: Small Shallow Draught Self-Righting Sailer

    You might also consider one of Parkers boats, notably the Presto versions. Or you might be able to get Roger Marshall to adapt the Presto 30 for wood construction now that the glass versions are no longer being made.

  26. #61
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    Default Re: Small Shallow Draught Self-Righting Sailer

    The search has come to a decision.: After considering a few other production boats such as recommended above, the substrate boat will now be a waterballasted Swallowboats BayRaider Expedition which in its standard form has an AVS of around 140 degrees. This boat will get a watertight hatch into the main cabin, and a buoyancy structure over the stern deck sufficient to destabilise the inverted boat enough to right it to an angle from where the standard water ballast will upright it fully. The boat will also get a different and somewhat smaller sailarea gunter yawl rig which will survive some rolling (with the sails, topmast and mizzen mast down and lashed horizontally overhead the cockpit). The mods will be carried out by a yard with expertise in ocean rowing boats under guidance of one renowned designer of such boats.
    Thanks for all the input here.

  27. #62
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Craic, you might find this blog by Dudley Dix on water ballast useful, very well thought through.

    Part 1 http://dudleydix.blogspot.co.uk/2014...r-ballast.html

    Part 2 http://dudleydix.blogspot.co.uk/2014...r-ballast.html

    Brian

  28. #63
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    Default Re: Small Shallow Draught Self-Righting Sailer

    I really like the Bayraider boats....I have never seen one in the flesh as it were but what I can see and read on the web. They look attractive and well thought out and well built on a lot of levels. Congratulations...

  29. #64
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Jim Michalak has a bunch of birdwatcher clones. Here is one. Sorta ugly and lowbrow, but also seems to tick the boxes.

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    Default Re: Small Shallow Draught Self-Righting Sailer

    Quote Originally Posted by keyhavenpotterer View Post
    Craic, you might find this blog by Dudley Dix on water ballast useful, very well thought through.

    Part 1 http://dudleydix.blogspot.co.uk/2014...r-ballast.html

    Part 2 http://dudleydix.blogspot.co.uk/2014...r-ballast.html

    Brian
    Hi Brian,
    thanks for this reference. Dudley Dix has excellent expertise with waterballast.

    However, in this above blog DD is discussing a somewhat different case from mine, namely that of a deep draught boat with fixed ballast keel which has ADDITIONALLY two separate waterballast tanks on port and starboard, one of which is empty while the other is filled. This setup is quite common in offshore race yachts to reduce leeward heel. DD discusses then the mechanics of how these boat can still self-right again.
    So his case is that of a "Asymmetric Capsize Buoyancy" -ACB- condition, rather than that much more interesting one of how a predominantely waterballasted shallow draught boat with a single ballast tank can still self-right unaided through using intentionally the unique specific of liquid ballast, which is the free-surface effect.
    Ballast water sloshing around in a single central tank may be a very awkward thing in an upright sailing boat, but -if properly designed- it may be a real blessing in an inverted hull.

    Admittedly, as the free surface sloshing is a dynamic condition, even a harmonic in connection with certain sea conditions, it is a much more complex feature to compute than that of static ballast causing ACB. But maybe there are smart thinkers out there to figure out how to describe the physics of free surface effects in ballast tanks.

    Claus

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    Default Re: Small Shallow Draught Self-Righting Sailer

    Hi Claus,

    I thought it was a very interesting piece in the way that the asymmetric aspects actually help ensure that the boat is less stable in the 180 degree inversion than would be the case with symmetrical ballast.

    It reminded me of Swallow Boats use of an asymmetric flooding tank on the BayRaider which also helped avoid the hull stability when upside down. I seem to remember some videos Swallow made of their first trials. Terrific thing for them to actually do the trials, video them and post them. Here is one http://m.youtube.com/watch?v=cL6xmOGCCOo

    The Expedition looks a super little boat and I look forward to seeing your modified version. Having done so much development work with Swallow it's good to hear you are going with them again for this new boat.

    Brian
    Last edited by keyhavenpotterer; 03-26-2014 at 05:03 AM.

  32. #67
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    Default Re: Small Shallow Draught Self-Righting Sailer

    Here she is.

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    Default Re: Small Shallow Draught Self-Righting Sailer

    I was immiediatly reminded of the "roamer" class dinghy with its additional cockpit additions, but that looks better! More details and photos please!

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    Default Re: Small Shallow Draught Self-Righting Sailer

    Two more photos, with the sails up, and with the oars in position. .
    Note, the mainsail shown is the smaller mainsail used for singlehanding on the Atlantic coast.
    I am to write an article on the project for a british boating mag, so will leave all details until then.

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    Default Re: Small Shallow Draught Self-Righting Sailer

    Yeah, dont give too much away or you will breach your contributers agreement more likely. You can come here AFTER you have been paid for your article. Nice one.

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