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Thread: lapstrake catboat designs

  1. #1
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    Default lapstrake catboat designs

    Is there a 15' lapstrake catboat design (with a cuddy/cabin) in the same range as Bolger's Catfish, or Witholz's Corvus? I suppose I could build another slabby plywood panel design...

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    Default Re: lapstrake catboat designs

    Google John D Little catboat images. I don't know whether he built to a design specific for lapstrake or just built the design that way from scratch. I think the later wouldn't be a problem in general.
    "... and the great shroud of the sea rolled on as it rolled five thousand years ago."

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    Default Re: lapstrake catboat designs

    Could a fellow "theoretically", or even practically, take plans such as witholz's, and round out the corners on the frames/moulds, and then use Oughtred's "Clinker" book to lay it up?

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    Default Re: lapstrake catboat designs

    I certainly won't venture an opinion on that. Seen too many ab**tions arise from tampering with proven designs. Changing weights, shapes, etc., are all more important design work than we like to think.

    Reminds me of the Onion's "Ask a Navy Seal'!

    http://www.theonion.com/blogpost/ask-a-navy-seal-12246
    "... and the great shroud of the sea rolled on as it rolled five thousand years ago."

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    Default Re: lapstrake catboat designs

    Recently found a plan from Bob Baker, a designer formerly from Massachusets, early to mid-20th century. The boat in the plan is described as "smooth planked." Would that mean carvel? or strip? When the plan is already round sided, could it be converted readily to clinker?

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    Default Re: lapstrake catboat designs

    Quote Originally Posted by Desert Rat View Post
    Recently found a plan from Bob Baker, a designer formerly from Massachusets, early to mid-20th century. The boat in the plan is described as "smooth planked." Would that mean carvel? or strip? When the plan is already round sided, could it be converted readily to clinker?
    Typically that means carvel in this context. Could easily be built lapstrake (traditional or glued) or strip-planked for that matter.

  7. #7
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    Default Re: lapstrake catboat designs

    I once lofted a symmetrically double ended multi (3) chined 18' dory stretching all of the longitudinals by 16.666% and all of the widths and heights by 8%. Then I bent a batten around the knuckles, transforming the hull from being multi chined to being round sided. From there I strip planked it with bead and cove 1/2" cedar. This boat has proven itself many times in harsh conditions, but I guess what you want to know is whether it comes out fair or not. It did, perfectly.

    That doesn't mean that it will work for whatever hull you're contemplating modifying, though I expect it would, but you can check it out on the loft floor if you want.

    Loft it up multi chined, assuming that's what you're considering as a starting point, then in the end view connect the knuckles with a batten making it round sided. Then, in the same view, draw in a few waterlines, measure the widths at the stations and draw them in on the plan (top) view and see if they come out fair.

    I was certain enough that it would work that I just made the forms, laminated the frames, then strip planked it without the lofting.

    You could also carvel plank it, strip plank it with thinner planks then add 2 or 3 layers of cold moulding, or clinker (lapstrake) build it.

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    Default Re: lapstrake catboat designs

    Gib,

    In the process you describe, did you use the knuckles as the high points, or the flats of the panel? if you use the knuckles, then you gain extra volume as you push the flats out to round. And vice versa, if you use the flats as your touch point for the curve, then you lose some volume as you knock the points off the knuckles. Does this matter?

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    Default Re: lapstrake catboat designs

    IMO doing what Gib did with a 'quartered symmetrical' design is a reasonable challenge with good potential to work out well and as envisioned beforehand. I suspect that with a catboat hull 'transfer' you'd end up doing a lot of lofting and checking and might not be really sure what your boat will look like in the building. Risk of being surprised, perhaps? Do you have time to look into other suitable designs already designed for round bottom construction? How about Winthrop Warner's Tid Bit? http://www.woodenboat.com/register-wooden-boats/tidbit The Catboat Association membership may well have numerous, proven, alternate designs to consider. http://www.catboats.org/
    "... and the great shroud of the sea rolled on as it rolled five thousand years ago."

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    Default Re: lapstrake catboat designs

    I wanted more boat, so I used the knuckles.

    It's a fact though, there are a lot of tried and true round sided plans out there already.

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    Default Re: lapstrake catboat designs

    15 years or so ago someone on this site did this. He used one of the hard chine wittholz cat boats. He kept the bilge as is, and increased the beam a little to get a round turn up to the sheer. This way everything under the waterline stayed the same. It came out really nice. Anyone remember his name?

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    Default Re: lapstrake catboat designs

    Lining off a 15' catboat for glued lap would be a fun exercise. I'd venture that it's totally do-able - providing you've done your homework, know what you need to know, and have both the eye and the patience for this sort of thing.
    Quote Originally Posted by James McMullen View Post
    Yeadon is right, of course.

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    Default Re: lapstrake catboat designs

    personally, I really like the cat designs overall. Myself, I lean towards the traditional lapstrake/clinker timber designs, instead of ply

    One of my favourites: http://forum.woodenboat.com/showthre...32#post2693332 Deer Isle Koster


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    Default Re: lapstrake catboat designs

    Quote Originally Posted by Dirc View Post
    personally, I really like the cat designs overall. Myself, I lean towards the traditional lapstrake/clinker timber designs, instead of ply

    One of my favourites: http://forum.woodenboat.com/showthre...32#post2693332 Deer Isle Koster

    A beautiful boat, to be sure, but not really a catboat: the mast is too far aft (cats are usually right up in the bow), and double ended (cat's usually carry a transom). Though some cats have a jib, a true cat would be just one sail.

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    Default Re: lapstrake catboat designs

    apologies, that is true, the mast IS rather far forward, also, the wide beam especially reminds me of the spirit of a cat

    didn't mean to go off topic, but I just love this one and thought of it reading this thread
    (its under 14 feet, with nearly a 6 foot beam 5'10" I believe)
    Last edited by Dirc; 09-14-2017 at 09:17 PM.

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    Default Re: lapstrake catboat designs

    Joel White's Marshcat has been built in lapstrake. You will have to add the cabin.





    Or who shut up the sea with doors, when it brake forth, as if it had issued out of the womb?
    When I made the cloud the garment thereof, and thick darkness a swaddlingband for it,
    And brake up for it my decreed place, and set bars and doors,
    And said, Hitherto shalt thou come, but no further: and here shall thy proud waves be stayed?
    Job 38: 8-11

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    Default Re: lapstrake catboat designs

    Thanks for all the replies, fellas. I ended up ordering the plans for Stambaugh's MEADOW BIRD 16. Yeah, I know, it's not a catboat; it's a gaff rigged yawl. It looks a lot like Garden's EEL, if it had a transom instead of canoe-ended. The plans arrived in the mail today, and I'm feeling quite pleased. Nine large sheets of fully detailed drawings, and nicely drawn too. A bargain at $85! I intend to start building small parts through the winter, and begin laying up planks as soon as weather allows in the spring.

    Thanks for all your suggestions! This place is the best.

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    Default Re: lapstrake catboat designs

    ... come on, got to at least include a few pictures of the design you chose!


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    Default Re: lapstrake catboat designs

    I went with the gaff rigged yawl version...

    Last edited by Desert Rat; 09-20-2017 at 11:04 PM. Reason: photo problems

  20. #20
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    Default Re: lapstrake catboat designs

    Also, I've included the stats below & I like your choice; more sticks to play with but overall more flexible
    Length: 16'-6"
    Beam: 6'-0"
    Draft: 1'-0" bd up
    2'-6" bd dn
    Weight: 650 lbs
    Sail Area: 140 sf

  21. #21
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    Default Re: lapstrake catboat designs

    "... and the great shroud of the sea rolled on as it rolled five thousand years ago."

  22. #22
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    Default Re: lapstrake catboat designs

    Quote Originally Posted by Dirc View Post
    Also, I've included the stats below & I like your choice; more sticks to play with but overall more flexible
    Length: 16'-6"
    Beam: 6'-0"
    Draft: 1'-0" bd up
    2'-6" bd dn
    Weight: 650 lbs
    Sail Area: 140 sf
    Per discussion with Stambaugh, I'm stretching the design to 18' LOD. Not sure yet about ballast, or keel vs. centerboard options. The original design was glued strip plank, and this one will be glued lapstrake ply (1/4" stock), and that will change some of the weight issues. Lots of variables in play still...

  23. #23
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    Default Re: lapstrake catboat designs

    Frederick Goeller 15' Lapstrake Catboat

    https://babel.hathitrust.org/cgi/pt?...39015022693371



    Simpler is better, except when complicated looks really cool.

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    Default Re: lapstrake catboat designs

    beautiful...

    someone should build her

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