Mysticshore 12 gets started.

Enough fooling around already! I've work the plans around enough it's time to see things happen. This is a continuation of the thoughts, ideas and plans developed in the this thread.

http://www.boatdesign.net/forums/boat-design/kayak-design-parameters-37739.html

This was my first attempt at a scarf in plywood. All went relatively well. My choice of weapons is shown. I didn't even try the power planer. My ply is 4 mm and a single "Oops!" could have ruined my day. I did some initial material removal with the block plane, but ultimately settled on the belt sander for the final fair.

I did a dry run on clamping the scarf. The ply is very flexible and the 4" tiles provided enough clamping pressure for the joint. I opted to use unthickened epoxy, coated the raw ends liberally and wet the joint again right before clamping.

 

The Layout

It's always nice to have your ideas carry though. I had created the flat patterns for my kayak through the flat pattern tools in Freeship. The basic shaped were exported to my CAD system where they were cleaned up and modified for their final output as full size templates. The PDF file was emailed off to the printers and a nice 16' roll of paper with some black lines was presented to me for a predetermined amount of cash.

The length of the patterns and the plywood was the same! I used a tracing wheel to transfer the lines to the plywood. The wheel leaves a series of small indentions that can be followed with your saber saw. I had the foresight to mark the back side of the ply so that any breakout would be inside the boat and most likely buried under an epoxy fillet.

I flipped the pattern and traced the second set of parts and mirror images. Instead of cutting the second half directly, I took the first set of "finished" parts and layed them in their respective tracings and drew around them in an attempt to maintain symmetry of all P & S parts.

 

Wired

I took the kids to the zoo. When we looked at the porcupines, all I could think about was the comdition of my boat. Everthing appears to be fitting together nicely. I'm impressed with how wellthe bow is fitting together. (the third pic) I like to tack my hulls together with small fillets between the ties. These tack fillets are really longer than I wanted. I was try not to waste material. The smaller fillets keep the hull a little more flexible. After the tacks are set up, the wires are easily clipped and removed.

Also with the tacks, it's easier to correct a misallignment by cutting the tack and reglueing. I had a hollow in the keel line that needed correction. I cut about two feet of tacks, spread the joint slightly with wedges and retacked the seam. Beat the heck out of of splitting a solid joint of or living with an unfair spouse...I mean joint.

 

Plans of attack.

I've got the fiberglass on order. I'm going to use 1" tapes on all of the joints. The exterior hull will be sheathed in the standard 6 oz. e cloth. The decks will be bright finished and will have a 4 oz. e cloth for lightness.

The 4 mm ply is actually a bit thinner than anticipated. I've ordered some 4 oz. s cloth for the cockpit area if I'm uncomfortable with material thickness after sheathing the hull.

I'm trying to monitor the weight of this kayak very closely. In my other builds, I was a little more casual about weight as they were prototypes and I was primarily interested in just ballparking the their weights.

Already, I can see that I most likely have too much peak to the forward deck and will need to adjust in downward. The upside is the 4mm ply is very flexible and might be able to accomodate a rounded forward deck, though it will have a seam in it as it was originally going to be peaked.

Another change from concept will be to increase the length of the cockpit opening. From the outset this was intended to be a heavier displacement kayak so that I could bring my young daughter with me. To enhance that idea, I believe a longer cockpit a little more mobility with in the boat. I can easily build a 5' cockpit. Along those lines of think, I toying with a seat track system that will allow for CG adjustment depending loading demands.

As the boat sit right now, I'm ready to position the permanent bulkheads and fillet them into place. I need to get the bulkheads permanently installed to hold the little vessel's shape. Afterwards, I'll (hopefully) fillet and tape the rest of the hull. Taping is so much easier on a soft fillet than a hard one. The stem and stern have already been filleted. I've cut 7/16" x 9/16" shelves, inwales, that taper at the ends. They will go in with or after the bulkheads and provide a landing for the deck.

 

I like... just curious about the reverse bits at the bow and stern...function or fancy? And just how did they come out in freeship?

 

Hey, Steve.

Purely aesthetic. I originally drew it on my single sheeter. It helped with the panel nesting if I recall correctly. I like the looks of it, though so I've been playing with it in subsequent designs. It does tend to fine up the entry and exit a bit, so it limits hull speed Cp's. I don't plan to operate at hull speed so it's not a big concern to me. I think that it helps keep the flow lines from transiting the chines a bit, but who's to say if there is any real benefit there?

Thanks for the interest.

Oh.....and Freeship eats it just fine. Every now and then I get a jog in a panel edge by the bow or stern. Especially when I have a curved stem/stern on the sheer strake panels. I can usually(alway?) get rid od the discontinuity by adding an edge that connects to the control point defining the curve section.

 

Progress

Had a busy week of working for a living, but managed to spend time on Mysticshore.

All of the bulkheads, seams and joints are filleted and taped. The sheer rail is in place and the exterior hull sheathing has been applied and is ready to be filled. Only one disaster. I let the hull go out of shape at the stern and in process of attempting to pull it back in, I blew out a the hull ply. A doubler was applied and progress continues.

The plan now is to fill the weave and hopefully do a test dunk this weekend to see how she floats. I'm working a couple of ideas for seating. I want an adjustable seat (for and aft) because I'm thinking that loading is going to vary and I want to have the control to keep her on her lines.

I'm working a couple of ideas to that end. One idea has a vertical keelson, 1/2" x 1", in the cockpit area that will be used as a central seat rail. The forward seat support will mirror the hull shape straddling the keelson and contain the locking mechanism. The rear support will be similar, but not as wide as the chine to chine plan for the forward. This plan would have me sheath the cockpit with 4 oz. s-glass to help support this seat arrangement as it will rest partially on the hull.

A second plan would be to have "floors" at predetermined locations, one for solo paddling and one for paddling with the wee folk onboard. Structurally, I think this plan is lighter and stronger as it will add integral floors to the plan and I could limit the s-glass use to only those areas the will be stepped on.

Things I would do different:

I would wire and fillet the garboard strake and bulkheads before adding the sheer strakes, I think. This would set the angle of dead-rise at each bulkhead location and lock those locations. There would still be longitudinal flexibility. It is so hard to stop wiring the panels together once they are cut and shaped. The drawback to locking in the shape is a loss in flexibility and the absolute requirement that the next panels fit well to the first. (Let's see what else we can blow out. )

The forward rake stern causes some build difficulties and I might consider setting the angle of that joint and glue it before wiring those panels to the garboard panels.

 

Clamp manufacturers just LOVE us boat builders... Looking good! Too bad about that blow out...but it should buff out. There isn't anything made of wood that can't be fixed...one way or another

 

Weight

18.8 pounds right now. I expect a doubling by the time all is done. 40 pounds won't be too bad.

 

Progress continues. The insides are epoxy coated except for the cockpit area as I have been waiting on a epiphany that has been slow in coming. I've roughed out the seat design. I'm shooting for an Adirondack look as it going to be a "picnic" kayak. I added a 2" glass tape for abrasion resistance along her keel, her stem and her stern. I doubled that with a 1" tape on her stem and stern. She is upsidedown right now for epoxy coats to build the thickness. I was trying to get three "hot" coats on today, but only managed two. Guess I'll sand tomorrow and go for two more coats.

The seat is going to nest in a set of cleats at the chine and the sheer clamp and rest on the bottom of the kayak. This was my epiphany, so to speak. A decision on my design direction. I will go ahead with my plan to lay 4 oz. s-glass in the cockpit area to handle the stress loads of the seat and entry and exit.

I have to say that the 4mm ply is just a shade on the thin side in this construction. In my last single sheeter that I built, I believe now that the ply thickness was closer to 5mm than 4mm. The 3/16" underlayment the I used for that developement was much more rigid. I'm seeing some unfairness/waviness along my chine lines that I'm going to partially contribute to the flexibilty of this thin material. I saw the same thing with my first single sheeter that I built with 1/8" ply. In that build, I planned to sheath the interior and exterior of the hull and that proved to be quite strong though I think heavier than the 3/16" with only exterior sheathing.

 

Nice...nice. Amazing what you can do with flat sheets of wood (product). I always love the look of the grain under a couple of coats of epoxy.

 

Hey LP, glad to see it coming together!

I've still got this plan in my "to do" file and even sourced plywood for it, but right now all my efforts are going into the cedar strip boat. I'll let you work the bugs out before I build mine

 

Yes. Nice work LP. This is my favorite
http://www.boatdesign.net/forums/at...1886-mysticshore-12-gets-started-img_0578.jpg
--- so far . Nice work.

 

Hey, Guys,

Thanks for the interest. Progress is coming to a screeching halt for a couple of weeks. Working for a living and all of that jazz.

I've been piecing together a seat. I think it looks nice. With my other kayaks, I've not been as careful with CG concerns as a should have been and did not place them as low as possible. !/2" is a substantial amount in a small boat. In the 2nd and fourth pictures, you can see where I've tapered the seat planks to lower the seat height as much as possible. This actually serves a dual purpose. Since the seat is resting directly on the hull planking, the tapered seat planks increase bearing area for transfering weight to the hull. In the long term, I'm thinking about shimming and shaping the central seat plank to further increase bearing area and transfer weight to the central keel tape and seam. Additionally, I may consider another layer of glass in this area of the hull.

The plan is to have two seat positions depending on how I'm using the kayak. If I was to only paddle solo, I would only use the forward, solo placement and make a fixed seat installation. In this case, I would incorporate the forward seat member into the hull where in would function as a floor to increase hull strength with no weight penalty due to a simplified construction.

The 4 oz. s-glass in the cockpit has stiffened the the hull nicely there.

CT--I was curious where you were. If you build, I've got two changes for you. Definitely go with 5mm ply. Most likely, you have read the whole thread, but I'll reiterate. The 4mm if very flexible and also thinner than I had anticipated. (4mm is 4mm is 4mm ) 4mm will work, but requires additional laminate that makes it heavier than if using the thicker material. The second change is the height of the forward deck. It was definitely out of proportion and so I've lowered it 2" at it's aftermost point.

 

Deck preparation

I'm looking forward to the deck installation

The after deck is a single piece. I've added a 2" tape followed by a 1" tape. I'm looking to add just a little bit of stiffening to the deck and this is a quick and dirty "hmmmm... I wonder if this will work." Looking back, I should have added a small and light wooden stiffener that would have fit under the 2" tape.

The forward deck is two pieces. Originally, it was going to be peaked, but with the flexible nature of the 4mm ply, I'm going with a curved deck. I undercut the lower surface of the central deck joint and filed it with thicken epoxy. I topped that with a 2' tape followed by a 1" tape. Third picture; poor man's vacume bag. (Note the aging hardener and the chrystalized resin ) I'm hoping the two layers will give enough rigidity to bend the sheets to the forward deck curvature. The proplem is that if there is not enough rigidity, the failure is most likely to be catatrophic. In which case, someboby is not going to be a happy camper. I may take a 2" strip of the 4 oz. S-glass to the outside before bending the panels.

Lastly, bow and stern details. The little rectangular pieces are where I'll put small eye-straps. I've been using small shock cords tied to eye-straps to hold bulkhead panels in place. I was going to hide them on the back side of the bulkheads, but this way, there is no doubt about their position.