bones

Sunday 4 April 2010: I only just summoned the will to proceed a bit further this weekend after picking up a cold weekend before last. But the time has come to get this one done. Last week I received 40 feet of 8 oz. polyester fabric from George Dyson. He shipped the day after I had emailed the order on the basis of my word that the check was in the mail. It arrived USPS Priority Mail from Bellingham, WA, 2 days later. Outstanding service. I was expecting that to take a week or two. I unpacked the cloth and rolled it onto a section of 4 inch diameter PVC tubing to let the creases resulting from being folded, to relax.
 
Today is a beautiful day, I took the frame out on the deck and cleaned up the deck stringers. I also cut a small piece of cedar gunwale stock to place on top of the masik to lift the forward deck stringers a bit higher. I put a couple of oak pegs in the the top of the masik to lock it in place and glued it to the top of the masik with some Titebond III waterproof glue.

I lashed all the stringers down and then brushed tung oil on the frame. I may add a lashing here and there to the bow and stern plates, and redo one or two lashings. But I think this is more or less ready to be skinned.

Time to review the videos at skinboat skool:
http://www.skinboats.org/skinboats/sewing_your_west_greenland_kayak.html

Instructions at Cape Falcon Kayak:
http://capefalconkayak.com/howtoskinakayak.html

And the relevant sections of Robert Morris's, Chris Cunningham's, Mark Starr's books on building skin-on-frame boats.

The bones are exhaling tung oil vapors this week and should be about ready for skin this coming weekend.

i torture the timbers

Sunday 14 March 2010: Over the last couple of weeks I have been experimenting with various ways to fail at steam bending a cockpit coaming from red oak. The process began in the last week of February when I sketched a coaming outline, 23 inches long by 16 inches wide out of poster board. I transferred this pattern to MDF and cut it out on the bandsaw. After drilling holes to allow for clamping, and hammering it all together I had a jig for steam-bending the cockpit coaming.

This jig is taken mostly from Chris Cunningham's book, Building the Greenland Kayak and uses a strip of aluminum flashing that wraps around the outside of the piece being bent to help support the wood and prevent splits from developing.

Though it is not the ideal material, I so far have nothing better to try than some kiln-dried red oak 2x4 from Home Despot. I ripped it down into strips about 1-1/4 inch tall, 3/8 inch thick. The strips were then cut to length -- the circumference of the form, plus 12 inches -- and then the 12 inches at each end are planed to make a long scarf joint where the ends overlap when wrapped around the jig. My first try almost worked. But I was too slow getting it clamped down, and it was a rather cool windy day, so that it came out somewhat asymmetric. The section near one end where I started the bend held close to the form. The other side and far end of the strip had cooled too much by the time I got it clamped and so didn't bend as easily. This resulted in a somewhat lopsided coaming. I may try to fix it with a heat gun. This is a general problem with the approach of bending by starting at one end of the strip and wrapping it around. You have to work very fast. It seems easier to get symmetry by marking the spot where the strip crosses the center of the cockpit at the front, clamp there first and work both sides back together. But that would make it more difficult to use the aluminum flashing to contain the strip. I'm still pondering whether the ability to brace the outside of the bend with the flashing is worth the potential for asymmetry induced by uneven cooling when wrapping around from one end to the other. I used the end-to-end approach with the aluminum flashing for 3 coaming attempts. But when I later tried to bend the coaming lips, I tried bending them from the front of the coaming symmetric around to the sides.

My second try at a coaming cracked right at the front of the cockpit, where the radius is the tightest due to some grain runout there. By the third try, I finally got a reasonable coaming.

This strip was just under 3/8 inches thick and was steamed for about 30 minutes before bending. I glued with epoxy thickened with wood flour and it looks good enough:

I have since failed on three attempts to bend a coaming lip from strips 3/8 inch by 3/8 inch. Two tries lost to grain runout; the third try today almost worked. The strip came out of the steamer very pliable and went around the form quite nicely. But it insisted on twisting so that the top of the coaming lip wanted to twist to the inside by the time it was wrapped all the way around. I was not able to fix the twisting before the strip cooled off too much and I snapped it while trying to get it to lie flat. Probably it would be better to bend the coaming lip around the bottom of the form where it can be braced against the base. I tried to bend it around near the top of the coaming where it would be in actual use but this made it easier for the strip to develop twist as I was bending it.

I finally was able to contact someone at Garman Brothers lumberyard near Annapolis to inquire about obtaining green, white oak. White oak or ash would be preferable for this purpose, especially if it was still green. I guess I'll try to get out there sometime this week to take a look. This is rough-cut lumber used for exterior fencing and construction so it sounds like a job to pick through and find some suitable boards. I may need to buy a planer, or find someone to surface it for me. Guess I'll take a look first to see if I can even find some suitable boards. This stuff is cheap at least. Exotic Hardwoods in Gaithersburg claims to have quartersawn white oak, but it is all kiln dried and expensive.

I also got in touch with George Dyson to inquire about material for skinning. He sent these PDF files describing the various weights and weaves of nylon and polyester fabrics available. I'm thinking about going with an 8 oz polyester skin and water-based polyurethane coating. I'll order the fabric this week. I also need to order vinyl material to make float bags. Float bags are necessary because this kayak will not have any watertight compartments. Inflatable bags maintain positive buoyancy in the event the frame is flooded.

The frame can be finished and oiled at any time and will then be ready to be skinned. If I can just get a reasonable cockpit coaming, everything will fall into place to finish this off.

installing the masik

Saturday 20 February 2010: By Friday night, I had developed a theory about how to replace the top of frame 4 with the steam-bent masik. I cut away the top of the frame with a Japanese saw and drilled holes near the top of the remaining section of frame 4.

I filed shallow grooves into the top of the gunwales so that lashings would not stand proud there because I want the masik to attach with a rabbet over the top of the gunwale. Then I re-lashed the frame to the gunwales using the holes I had drilled in frame 4.

I cut rabbets into the end of the masik, and then chiseled a groove to lock over the top of frame 4.

I drilled two holes trhough from the top of the masik at each end to accept lashing and lashed it down to the gunwales. It was a little tricky to figure out a way to lash these joints. I didn't want to drill holes in the gunwales, and that little section of frame 4 on one side tends to get in the way of some of the more obvious lashing patterns. But this seems quite solid the way it is and looks like it will do. I could peg the masik into the gunwales but I think this is strong enough.

straightening things out?

Saturday 20 February 2010: Tuesday and Wednesday, with the frame off the strongback and resting between two sawhorses, I eyeballed it from various perspectives and bent and twisted it a little between the sawhorses to tweak the alignment. It looks pretty fair and straight after that. In hindsight, it would have been better to have done this before I pegged the gunwales to the stem plates. But is seems possible, by gentle pressure on the frame at the right angles, to be able to adjust the way the lashings sit slightly. Or maybe the frame was just already straighter than I had been thinking? At any rate, it seems to me that a good strategy for winding and alignment might be to lash things up on the strongback as carefully as possible. But then take it out, turn it over, sight down the keelson, push it and twist it and adust it until it lies just so; and then peg the gunwales to lock it down tight.

I've been staring hard at frame 4 over the last week trying to visualize how to attach the masik and whether to cut to top of the frame away to do it.

masik

 

Monday 15 February 2010: The masik is a curved deckbeam in a traditional Greenland kayak that lies just before the cockpit. The knees slide under this beam, and one uses upward pressure of the top of the thighs, or knees against the bottom of the masik to brace when leaning or rolling. Frame 4 in the Sea Rider lies at the position where the masik would be in a traditional kayak. An advantage of a traditional masik over the 12 mm marine ply from which frame 4 is constructed is that a true masik is much wider and so provides a more comfortable surface against which to brace than would the thin plywood of frame 4.

And so I have wanted to make a real masik for this boat. I had tried steaming and laminating 2 strips of red oak about 3/8 inch thick and an inch and a half wide. They bent fine and held their shape well. But because I didn't build a full jig to clamp them, there were small gaps between the strips around the areas near where the bend was the greatest. I also didn't like the fact that at 1.5 inches wide this was still a little narrow. Looking at the way the masik is built in Chris Cunningham's and also in Mark Starr's books on building traditional Greenland kayaks, and also at this nice photo gallery by Bryan Nystrom: Steam Bent Masik, I decided to give that technique a shot.

First a blank is cut from a red oak 1 by 3 inch board:

The blank is cut on a bandsaw so that it thins to about 7/16 inch in the center, leaving the full thickness at the ends. This was steamed for about 30 minutes and then clamped:

 

After cooling and sitting, when released, there is some springback. But it looks pretty good. I round over the edges, then finish it with a belt sander and it is now ready to be fitted to the gunwales. I think I will cut out the top of frame 4 to install this. But I am still contemplating exactly how to place and attach the masik to the gunwales and whatever I leave left at the top of frame 4.

shall we move on?

Monday 15 February 2010: I grow tired of fooling around with the bow. I cut it completely apart, tweaked, adjusted, pegged the gunwales and re-lashed it over the last few days. Staring at it hard and trying to discern where anything might be off-kilter. It is nice and plumb now and looks pretty good though the gunwales and chines are starting to look a bit ragged from being hacked at too much. But, though the bow looks ok now, the keelson doesn't lie as straight as I might like. It seems to lie about a quarter inch to port of dead center at frame 4, just before the cockpit, about the longitudinal center of the boat. This curve is just discernable to the eyeball if the boat is upside down and you sight down the keelson. It is more easily noticed with the laser level sighted down the keelson. I don't think I can do a whole lot better than this without substantially cutting things apart and perhaps this is good enough? I'm still pondering that thought. I've noted before, the whole frame is flexible, a bit basket-like, and the position into which it relaxes varies somewhat and can be pushed around slightly. As the boat is skinned and eventually when it sits in the water, under the weight of a paddler, equilibrium will happen at some slightly other unpredictable line. So I am sure there is a point where it is counter-productive to worry about minor anomalies in alignment. Am I at that point yet? That is the question.

Otherwise, the gunwales, chines, keelson and stems are fully lashed. I have taken the frame down on the floor and tried sitting in it to see how it fits. It is tight. It seems that my legs are not long enough to quite use frame 3 for a foot brace. I may need something as much as 6 inches forward of frame 3 if I want to use a foot brace in this boat. I ordered some bundles of 4 and 6 mm okuome marine ply to make a footbrace, and cockpit floorboards. But UPS has been freaking out over the weather and has still not delivered that. First missing last Friday, and then again today. Perhaps tomorrow?

fixing the bow

Thursday 11 February 2010: Another 4 hours of shoveling today. Snow from the whiteout blizzard yesterday was only maybe 8 to 10 inches. I cleaned out the street in front and then did about half the downhill neighbor's street. He is getting pretty frail and I didn't see him come out today. Some clowns left their BMW parked in front of the fire hydrant all day yesterday during the storm. Possibly it was difficult to see when they parked, but not really. I had dug it out completely and the yellow painted curb as well. But then I guess there was the whiteout thing going on. They showed up while I was shoveling, apologizing and trying to shovel out for me with a little garden spade. I just laughed, helped push them out and got rid of them so I could finish things off.

I also got the ladder and cleared most of the snow on the front porch roof since it is flat, old and leaky and had probably over 20 inches of wet, heavy snow sitting on it. No, I did not climb on the roof. Just stood on the ladder and used the snow shovel to undercut, and slide the snow off. That got most of it and was pretty easy aside from wrestling the ladder out from the backyard, wrangling it around the porch and then putting it back.

I released the clamps holding the masik pieces and they held their shapes probably well enough to do.

 

So I slathered them with titebond and clamped them back together. We'll see how well this worked out tomorrow. 

I cut the bow apart and started carefully relashing it with the laser out of the way and lining things up by line-of-sight as I lash it all back down. I'm much happier with the result. Still have some more lashing to tie and then I'll re-peg the gunwales and chines to lock everything down. Hopefully it will look a little better this time. I'm obsessing a little much over alignment and symmetry although the whole thing is a bit like a basket. You can pull and stretch deform things in various ways. Presumably, when a paddler is sitting in it paddling, the whole frame will be shifting, twisting and flexing through the water like a fish. But it can't hurt to pay as much attention to lining things up nice and straight as I run the lashings.