lapwing hull #7

[herbt]

Lapwing hull #7 is now under way. Got the stem assembled, the bulkheads cut out and am in the process of making up the transom.

Has anyone considered stitching on the strakes -as in stitch and glue - instead of clamping?

Tom, the folks at World Panel Products - Al Jernigan and crew were great, I recommend them to anyone looking for high quality marine grade products.

Herb

[John Turpin]

Great news! Keep us informed of your progress.

I never considered stitching the strakes, but I did use drywall screws quite often to force planks to go where I wanted them.

Post photos of your progress when you can. Welcome aboard.

[Diddle Dally]

Maybe you could go where no man has gone before!!! I suppose you could try it, and figure out pretty quickly if it is possible or not.  :? Have you asked Graham?

[herbt]

Not yet, just started thinking about it.

Herb

[herbt]

Getting to the point where I need to scarf some ply together. Attached ( I hope) are some shots of a scarfing jig I have used for years and it gives a perfect scarf every time. The one shown will scarf ply up to 9mm. for thicker ply you can increase the angle a bit.

Make the jig with 3/4 stock and attach at a 9 degree angle then attach to the base of your circ saw as shown.

wire back the guard

the ply must be on a flat surface with about 4 -5 inches protruding so the blade will just clear the table.

clamp a straight edge on the ply aprox 3

[Tom Lathrop]

Yeah Herb,

Al and the rest of the guys at World Panel are great to deal with.  It does help if you know the material you want though.

Thinking about stitching the panels on a lapstrake?  I think it would be far more work and no advantage to using the plywood clamps and wedges.  Lots of holes to drill and clean up.  Can't make small adjustments after the holes are drilled.  Think I'd forget about it.  

CLC uses what they call the lapstitch method but they also have CNC cut and fitted strakes.  Like the usual S&G boat, I think they can stitch up the whole boat before gluing up.  No way you can approach that accuracy in cutting parts.

[Docpal]

I know that at least one person on this Forum has access to a Shopbot CNC router  via the "Techshop" in Durham ( http://www.techshopdurham.com/ ). Even if you are not a member you could probably get someone there to cut out these FREE files to build a 13.5' lap strake canoe developed by Bill Young of Seaside Small Craft, in Willis Wharf, VA.  (http://www.shopbotprojectwizard.com/pw/products.aspx?product=11&id=11). I've built 4 of them and they all use the plastic wire tie "connections" to hold each plank in place while you are doing the initial epoxy work. She finished up at about 30 pounds with trim, etc. Tom is correct however when he says that if you are cutting out your parts with conventional tooling you would be hard pressed to get the accuracy needed to make this technique work.

The process was so simple I even built a few "test" hulls out of Luan, and turned one of them into a trimaran.....Unfortunately that added a bit too much weight, and I now own one of the few semi submersible lap strake vessels on the planet....

[herbt]

Well dont feel too bad Doc, all boats are semi submersible.

Got the idea for stitching the strakes from building two CLC skerry's from plans. They worked out well but they did provide measurements for all of the strakes.

Herb

[Tom Lathrop]

Graham and I visited Bill Young's shop in, I think, 1995 when he only had the early and fairly primitive ShopBot.  I also saw his first attempt at this method at the festival in St Michaels.  I assume things are much improved since then, especially on the software end.  I'd be interested in how the mold built vs lapstitch compare from someone who has built both ways.

[Ken_Potts]

  Hey Herb, now that Docpal has mentioned it I do have a Techshop membership if you want to cut molds or other stuff out on the shopbot.

  Strangely, all of the curvy cuts I've been doing on my current project are done with the bandsaw and the sander that are in the room adjoining the shopbot room...  :shock:

[herbt]

Well I am ready to set the parts up on the horses tomorrow. weather is so cold its getting hard to keep heat in my shop.

probably be about 1-2 weeks before getting around to the strakes. will probably make full size patterns for the strakes  from cheap luan before cutting okoume. A little extra work but probably worth the effort and might save time and money  in the long run.

I would assume that shop bot would need all of the lofting info for the boat?

Herb

   

[John Turpin]

will probably make full size patterns for the strakes  from cheap luan before cutting okoume. A little extra work but probably worth the effort and might save time and money  in the long run.

Very good idea.

[paul_stewart]

will probably make full size patterns

For making full-size templates I've liked using 1/8" x 4' x 8' sheets of hardboard with one side being smooth gloss white and the other side being dark hardboard ("Masonite"?).  Lowe's sells it as "Thrifty White Hardboard Wall Panel".   A couple of years ago at Lowe's it was about $10/sheet;  now, it's almost $12/sheet.   In your location it may or may not be cheaper than luan sheets.  I think it may be a little more flexible/bendable and easier to cut than luan.  The material is very uniform.  Cut edges can be sanded or planed back to a drawn line.   The smooth white side is nice for drawing and marking.  

If your full-size patterns need to be thicker than 1/8" then that hardboard may not work for you.

Currently I have a few of those 4x8 panels covering the carpet in our basement workshop, taped together, while we are building a 17.5' B&B Grand Diva kayak  (picture below.) It beats tripping over plastic sheeting or a drop cloth.  Things on wheels roll smoothly on it.    

--Paul

( B&B Grand Diva kayak CNC-cut  http://sandybottomkayaker.blogspot.com/2009/12/ready-go.html )

[herbt]

Thanks for the tip Paul.

I will look for it

Herb

[Ken_Potts]

  Yes - The shopbot would need all that info.  I haven't seen the plans but I suspect that they show dimensional information for the molds the boat is built over and the planking is cut to fit.  If that's the case the shopbot would be good for cutting out the molds but not the planks.  It wouldn't be too difficult to model and cut out.  Then again it's not too difficult to lay things out by hand either - Just a matter of where you want to invest the effort.

  Let me know if you'd like to go the computerized route.  And either way, post lot of pictures of the project  :grin:

[herbt]

Progress to date.

Starting to look like a boat.

[/img]

[DeanHerring]

holy cow Herb! I'll be right over... :-D

[John Turpin]

Looks great!

[Ken_Potts]

Slow down Dean!  There are a few more parts to put on before you can sail her!

Thanks for the pictures Herb - I'll scratch the frames off the shopbot to-do list 

[herbt]

Ken

I think if I thought I was going to build a bunch of lapwings the shop bot would be a good way to go but for a one time shot maybe not.

Tomorrow I put the inner keel and stem on and after taping the joints and fairing off we will be ready for the strakes. Dean wanted to take it for a sail yesterday but I thought it might be a little tender.

Thanks for the input.

Herb