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Thread: Coquina

  1. #106
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    Default Planking

    Continuing on from the previous post.....

    OK I chickened out no spiling going on here the plans include a plank layout grid so I have cut out all the planks slightly oversize.

    The garboard is then temporarily fixed to the molds and the plank marks on the molds are compared to those on the plank. Again I am amazed, no extremely pleased (don't want to insult Mr. Hylan) to find they correspond within a bees bum, apart from the station 2 and 18 which are the first and last molds. These points are within about an 1/4" at the bow and I put that down to a slight difference in batten spring. The pattern grid differs to the mold spacing so I am guessing that may explain the difference. At the stern it's under an 1/8th so I'm not to fussed back there.

    The second pic shows the discrepancy fortunately the plank is wider than the mold mark so some adjustment could be possible. With that in mind I went ahead and cut the plank to my layout lines. Now the issue I have is do I adjust back to the mold ticks or just leave it. To my eye the plank edge is fair in fact if I follow the mold I think the sweep up to the stem would be exaggerated.

    I have read repeatedly that a fair plank curve is more important than following the mold marks and if the difference is under 1/8" ignore it but I've got 1/4" +/-. Hopefully the pics show the state of play and any advice from experienced builders will be appreciated.

    Attachment 143135Attachment 143136Attachment 143137
    Mike
    "Working to a rigidly defined method of doubt and uncertainty"

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  3. #107
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    The bottom edge of the next plank is the bit that's visible.
    If the top edge looks fair (and is adequately overlapped by the next plank)
    does it matter ???
    cheers
    AJ
    (the incredibly lazy)

  4. #108
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    Quote Originally Posted by b.o.a.t. View Post
    The bottom edge of the next plank is the bit that's visible.
    If the top edge looks fair (and is adequately overlapped by the next plank)
    does it matter ???
    cheers
    AJ
    (the incredibly lazy)
    Good point AJ but the gain runs into this area so there is no room for adjustments after it is cut.
    Mike
    "Working to a rigidly defined method of doubt and uncertainty"

  5. #109
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    Default

    This might be stating the bleeding obvious, but is there any room to nudge the planks down to the mark without their bottom (ie roofwards) edges going below the line of the stem? I mean just the forward end. It just looks in one of the shots as if the plank has a bit of extra meat above the edge of the stem...? Because the plank twists there it is easy to lose that height as the board 'pulls itself' up to begin the twist, so maybe encourage it down?
    What caused the Pacific War? A book to read: here

    http://middlething.blogspot.com/

  6. #110
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    Default

    I always tried to make the upper plank edge fair, just for looks, but I'm fairly anal about such things. It really doesn't matter from a strength point of view, if there's some waviness to the curve.

    I'm not sure what you mean Rob, but I would think there's going to be a false steam over the exposed plank leading edges. Other wise the planks would fall into a rabbit.

  7. #111
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    Yep, I agree, I mean I assume the bottom edge will end up flush on the stem, but I'm just wondering if it is sitting a little proud now and could be pulled downwards.
    What caused the Pacific War? A book to read: here

    http://middlething.blogspot.com/

  8. #112
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    Default

    Thanks for the replies gents.

    Quote Originally Posted by rob540 View Post
    This might be stating the bleeding obvious, but is there any room to nudge the planks down to the mark without their bottom (ie roofwards) edges going below the line of the stem?
    I get what you are saying Rob, to be frank even though it is a skinny little plank the twist is great. I'll give nudging it a bit a go but I think I'll end up with a lot of tension away from the mold with resultant bumps.

    Quote Originally Posted by PAR View Post
    I always tried to make the upper plank edge fair, just for looks, but I'm fairly anal about such things. It really doesn't matter from a strength point of view, if there's some waviness to the curve.

    I'm not sure what you mean Rob, but I would think there's going to be a false steam over the exposed plank leading edges. Other wise the planks would fall into a rabbit.
    There is an outer stem to go on and I maybe over thinking this Paul as it is the first time I've had a go at it. Besides wanting it to look fair I'm concerned about what this initial discrepancy may do to the run of the other planks. Perhaps I should test fit #2 and sit awhile in the moaning chair to look and ponder.

    Quote Originally Posted by rob540 View Post
    Yep, I agree, I mean I assume the bottom edge will end up flush on the stem, but I'm just wondering if it is sitting a little proud now and could be pulled downwards.
    Rob the plank lies spot on at the stem assuming I marked the stem correctly. I may be off track but if I start adjusting the marks at the stem for one plank I believe I really should redo the lining off for all planks, yes and what a horrible thought. Now if I had spiled the garboard we would be talking about how I cut it to narrow.
    Mike
    "Working to a rigidly defined method of doubt and uncertainty"

  9. #113
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    Default Pondering

    Ponder -vb
    to give deep or thorough consideration

    Well I looked and I pondered I reflected and I deliberated, hell I even ruminated and after thinking about it some more I decided to recut the upper edge of the garboard.

    At the end of the day I figured Mr. Hylan knows more about fair lines than I do so I reckoned it was best to follow the mold ticks than my sprung lines on the plank.

    With the plank firmly screwed to the molds a thin batten was employed to re spring the line from the stem to station #2. Then after removing said plank and pining to the second one I carefully planed back to the line with a block plane.

    It's amazing how accurate one can be by skewing the plane through the curve which adjust the cut as you go, but I guess you already know that.

    Anyway the amount removed was a little over 3/16th inch and while it is hard to tell the before and after difference I think it is worth the hassle.

    I cut the gain so should be able to glue one side up this week.
    Mike
    "Working to a rigidly defined method of doubt and uncertainty"

  10. #114
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    Default 1st plank

    Port Garboard is glued without too much drama although I wish had arms eight foot long arms as I managed to drop the plank across my freshly applied epoxy thus requiring much scraping and causing consternation as to the amount that remained for the joint.
    I pressed on regardless and fortunately the squeeze out looked good.

    During the dry fit I decided to cut a small gain at the stern rather than deepen the jog thinking this will give a slightly more delicate look. Hope I can achieve consistency across all the planks and it turns out OK

    Sorry if I'm boring you but this is a bit of a milestone for me so here are some pics. I promise I won't post pics of all the remaining 23 plank glue ups.

    Attachment 143783Attachment 143784Attachment 143785Attachment 143786

    Things are ready for the stb side but it's freezing in the shop tonight so I might wizz out for a while and make a marking gauge to cut the plank ends on the transom instead of gluing.
    Mike
    "Working to a rigidly defined method of doubt and uncertainty"

  11. #115
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    Default

    Nothing boring there
    Although you are doing intolerably tidy and neat work.
    Noted too is the complete absence of shavings, chips, food wrappers and dust. It is obvious to me sir, that you are failing to make adequate mess and should be penalised.
    What caused the Pacific War? A book to read: here

    http://middlething.blogspot.com/

  12. #116
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    You are to kind Sir, I'll take a pic of the floor to show you I am indeed a slob.

    Now on another well known forum about wooden boats there resides a thread reporting on the 2010 Small Reach Regatta held in Lamoine State Park, Maine and guess what a couple of Coquinas were entered. They are even more beautiful on the water if that is possible. Of particular note is the cut and set of the sail in the first pic, fantastic.

    forum.woodenboat.com/showthread.php?118050-Small-Reach-Regatta-2010-picture-thread&p=2675664#post2675664 is a link to a couple of sailing pics hope I'm not contravening forum etiquette for either forums.
    Last edited by m2c1Iw; 6th August 2010 at 12:45 AM. Reason: edited link
    Mike
    "Working to a rigidly defined method of doubt and uncertainty"

  13. #117
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    Default Scarfing

    I'm preparing the outer keel and do not have a long enough length of stuff to use. I've got some celery top pine in 2.3m lengths but unfortunately it has a couple of defects which means three scarfs.

    My question is would an 8:1 epoxied scarf be OK. The keel is 3/4" finished (sided). My reading says between 8:1 and 12:1 but my I wonder if 12:1 is an over kill and more suited to planks with greater bend and twist.

    Actually should I just go and find a long bit of some thing Oregon or Hoop is the most likely candidate.
    Mike
    "Working to a rigidly defined method of doubt and uncertainty"

  14. #118
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    The outer keel is generally a sacrificial piece, so the 8:1 scarf will be fine, though if the scarf falls on a fairly substantial portion of rocker, then increasing the scarf ratio may help it "lie down" better. With epoxy as an adhesive, you can generally use 8:1 or less for most stuff.

  15. #119
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    my main concern was the centre board slot so I've made sure the scarfs avoid that. The rocker is not that severe so I think it should be OK at 3/4". It's getting hard to find 5m lengths so I'll go ahead and scarf.

    Cheers
    Mike
    "Working to a rigidly defined method of doubt and uncertainty"

  16. #120
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    Dec 2008
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    Reeves Plain, South Australia
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    Default Coquina outer keel

    I have a couple of pieces of absolute straight and close grained douglas fir that is pretty hard that are nearly 5metres long. they are about an inch thick and 2inches wide. While I'm absolutely sure that the 8:1 scarph proposed will be fine (so long as the feather edge if any, faces aft), if you thought that these would be wide enough laminated longitudinally I would be delighted if you could use them. I'm not at home at the moment so I can't give you exact measurements but will be back on Friday 13th when I will dig them out and post the exact measurements. Thanks for your continuing posts on Coquina - I'm rapt.

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