How strong is a skin-on-frame sea kayak? (Destructive testing)

How strong is a skin-on-frame sea kayak? (Destructive testing) from Baby Seal Films on Vimeo.

 

Katya Palladina was given this skin-on-frame kayak by Phoxx Ekcs after he completed his expedition along the north coast of Vancouver Island in 2011. After 7 years of regular use, it's time to replace the skin and do some minor repairs. This gave us an opportunity to conduct some destructive testing.

We tested the strength of a the nylon fabric skin prior to completely removing it in preparation for re-skinning. It resists blunt force very well but can be punctured by a sharp point. Typically when this happens it's because of dragging against oyster shells or large barnacles. The skin comes off easily from the wooden frame after softening the resin with a heat gun.

This kayak was designed by Kiliii Yu of Seawolf Kayak and built by primitive skills expert Phoxx Ekcs.

It doesn't seem right to destroy this kayak without a reference to the amazing journey Phoxx Ekcs took this kayak through. The full story can be found in our interview with Phoxx on YouTube:

TRAILER

PART 1 "Living Primitively"

PART 2 "The North Coast Trail"

PART 3 "No Limits, No Regrets"

PART 4 "My Most Dangerous Day on the Water"

Reskinning My East Greenland Replica Kayak

East Greenland replica kayak, at Dash Point beach.

 

Here are some new pictures of my East Greenland replica kayak, built from Howard Chapelle's 1948 Greenland kayak survey published in Adney and Chapelle's book The Bark Canoes and Skin Boats of North America (figure 208).  She has a new nylon skin!

 

I cut the old skin off in October because it was peeling and I wanted to make some small adjustments to the frame.  After repairing the frame I let it dry out for a while and eventually got around to putting a new skin on, but then left it unfinished for several weeks over the holidays.  I never did get up enough enthusiasm to finish the project.  Luckily, Ricardo had been skinning a kayak at Bates Boatbuilding and offered to finish the project for me.  So I brought my kayak and skin kit over to their shop and he and one of the students finished the stitching, dyed the skin and sealed it with Corey Freedman's famous two-part polyurethane Goop.  And it didn't cost me a thing!  (Although to show my appreciation for all of their hard work I bought a copy of Woodstrip Rowing Craft for the Bate's Boatbuilding program's library).

 

She seems faster now. Maybe it's because she's lighter since the frame is dry and no longer waterlogged. I think taking off the protective rubstrips helped a lot.

 

This time I wanted the seam in the center of the deck instead of having it wander around randomly. The skin turned out a little more wrinkled on the deck than it did the first time although it doesn't make a difference in performance.  I added a couple thin, flexible cedar floorboards to replace the foam pad I was using as a seat. They are actually quite comfortable. I think it's a big improvement in the seat since the foam pad took up a lot more room and prevented water from draining out. 

 

The dye is Jacquard Acid Dye, 1/2 ochre, 1/2 brown and a pinch of amber.  You never know what you are going to get with this dye but the color came out exactly what I wanted, which was more of a rawhide look, translucent enough so that more of the frame shows.

 

Now that I know how much work goes into to reskinning a kayak, I'm going to take much better care of this new skin!

 

Glossy new skin, with middle seam on the deck.

I replaced the foam seat with thin wooden floorboards.

Kayak Log Racing with Brian Schulz of Cape Falcon Kayak

Kayak Log Race with Cape Falcon Kayak from Baby Seal Films on Vimeo.

Last weekend Richard Lovering and I drove down to Nehalem, Oregon to attend a kayak log race hosted by Brian Schulz of Cape Falcon Kayak. The race was Brian’s clever way of getting a bunch of people to pull some very large logs 3.5 miles down the Nehalem river for him for nothing. Actually he offered a number of prizes, including either a skin−on−frame Greenland kayak or red plastic river boat (winner’s choice), a used copy of Harvey Golden’s book Kayaks of Greenland, model kayak frame, and a bottle of beer. 

Richard in a skin-on-frame Adirondack guide boat, built by Brian Schulz.

My purpose there was to serve as a videographer and safety boater, so Ricardo and I actually didn’t pull any logs. Brian equipped us with his expertly-crafted skin−on−frame Adirondack guideboat, which worked perfectly as a stable platform for photography. For its size the guideboat is amazingly lightweight, maybe a little over 40 pounds. It has an incredible capacity for gear. We sat on the ends with a crate between us filled with extra tow ropes and a bilge pump.  We also had a chainsaw, and my personal bag with my cameras, extra clothes, shoes and snacks.

 

That boat can really move! The only thing I didn’t like was how Brian had fixed the oars to the oarlocks, which kept them from popping out but prevented you from rotating them along the long axis to angle the blades. 

Skin-on-frame Adirondack guide boat, built by Brian Schulz at the Nehalem boat launch.

You couldn’t have asked for better weather for an event like this: a little frosty in the morning but dry and sunny with a perfectly clear sky. We had over a dozen people pulling 7 very large logs. I didn’t really get a sense of how big the logs were until the end when Brian had them roped together at the dock at the Nehalem public boat launch. The plan is that Brian and Mark Whitaker are going to somehow pull them out of the water and then process them using Mark’s portable sawmill.

Mark Whitaker, securing the logs together at the Nehalem boat ramp.

I wish we had had more time to spend down there. Richard and I were drooling over Brian’s awesome workshop (the big red barn you see in the beginning of the video) and all the tools, stacks of wood, a few steam−bent kayak coamings, and completed kayak frames he had lying around. Brian says he can knock out a frame for an experimental prototype kayak in a day. He will find out quickly how it paddles with a Saran Wrap test, then tosses it onto the pile of other old frames when he's done.

Rebuilding the Frame on a Skin-On-Frame Greenland Qajaq

Here are some pics of the frame after I took the skin off my Greenland kayak, based on fig. 208 of Adney and Chapelle's book The Bark Canoes and Skin Boats of North America. I took a block plane and shaved off any residual polyurethane where the skin adhered to the gunwales and chine stringers.  

 

Pulling the skin off took some big chunks off the keelson, so I ended up completely replacing the keelson. First I cut all the lashings which held the keelson to the ribs. Then I cut the keelson off the stems by sawing the pegs in the joint between the keelson and the stems.

 

I happened to have a piece of cedar ready that was the perfect dimensions for a new keelson. It was left over from the build two years ago and I had been using it as a batten for lofting my sailboat. I attached the new keelson by extending the notch in the bow and stern stems and pegging it in place. But it wasn't as simple as all that: the old keelson was unfair and had quite a few unsightly humps and valleys, so I spent a lot of time fairing the new keelson with fairing blocks (between 1/8th and 1/4 inch deep) placed between the new keelson and ribs. The old keelson also was crooked near the stern, which explained the tendency for the boat to pull to the left.

 

 

 

On the deck I moved the forward deck stringers closer together medially. This way my knees would hit the underside of the deck skin lateral to the deck stringers. Previously my knees would hit the stringers themselves which was a little uncomfortable. During rolling my knees sometimes would slide off the stringers, but now the stringers would help keep my knees from sliding.

 

In the cockpit I lashed in a couple floorboards. The idea here is to keep my butt from making a big lump in the skin which might slow the boat down. I'll be sitting on a doubled-over foam pad. If the floorboard turns out to be too uncomfortable I can always cut it out.

 

Another modification I did was to bring the forward ends of the chine stringers up about an inch to give the bow a finer entry. It will be interesting to see if this affects the performance in any perceptible way.

 

Lastly I brushed the frame with a couple generous coats of tung oil. I was happy with the choice of tung oil because it's thin and penetrates like water but hardens to a dry finish -- much better than the linseed oil I've used on previous kayaks, which is known to promote mildew growth anyway.

 

Shedding My Skin

I know I said I wasn't going to be doing any boatbuilding until the end of 2009, but the reason for that was partly to to give myself time for maintenance of the boats I already have.  So now I'm starting my long list of kayak projects.  First of all, I'm reskinning my historic reproduction of the Howard Chapelle's 1948 Greenland kayak, fig. 208 of Adney and Chapelle's book The Bark Canoes and Skin Boats of North America.

Here is what my kayak looked like after two years of regular use and storage outside: generally in good condition except some wear around the coaming, especially the back deck, and where my knees and feet pressed against the underside of the foredeck. Also, the thin coat of one−part polyurethane that I put on is flaking off from the underlying two−part polyurethane. Brushing on that coat of one−part hardware store polyurethane was a big mistake. I did it purely for cosmetic reasons, to cover the glossy sheen of the two-part polyurethane. It lasted a year before it started to peel off.

If it wasn’t for all the unsightly peeling I probably wouldn’t have bothered replacing the skin for another few years, but it had gotten just too embarrassing to show off anymore. So I finally took a box cutter to the skin and pulled the whole thing off. This also gave me the opportunity to remove the rub strips I glued and pegged to the keelson and chines. Although they were traditional, the skin was plenty abrasion resistant by itself so they really weren’t necessary. I also suspected they added some drag and slowed the kayak down. I also wanted to tweak the frame a little, giving the bow a finer entry and see if I could finally figure out why the kayak tended to pull to the left. 

The skin adhered well to the frame. I was able to pull it off, but had to cut the skin into several pieces to make it easier. In some areas, it stuck so well to the frame that it tore chunks out of the gunwale and keelson. Whether that happened depended on if I was pulling the skin with or against the grain. If you ever do this yourself, I recommend that if you start tearing pieces of wood out just pull in the other direction. 

The frame looked like it held up well. The lashings were still tight, except for a couple lashings in the floorboards.  No signs of rot, but the frame felt wet and heavy. It was probably seasoned like driftwood. I found pockets of sand at the ends. I suspect that it never completely dried out since the first time I took her out. The moisture would explain the significant weight gain over the years: the day she was completed she weighed 29 pounds, but last year in the middle of winter she weighed 44 pounds. Originally, I didn't oil the frame because I thought it an unnecessary step to preserve the wood which would be constantly exposed to saltwater. But this time I’m going to coat it generously with tung oil to see if it will inhibit the absorption of water and keep the weight down.

Next step: repairing the frame

Super Secret Kayak Project X Revealed at SSTIKS 2008!

Remember Super Secret Kayak Project X that I reported about back in February? That was the skin-on-frame kayak commissioned by Dick Mahler, designed and constructed by Portland, Oregon kayak builder Lodro Dawa of Monkcraft Kayaks. Well I missed the South Sound Traditional Inuit Sea Kayak Symposium (SSTIKS) this year so I didn't get to see it unveiled.  

The kayak is a three piece Greenland-style skin-on-frame. It has watertight hatches and bulkheads which attach together with bolts. Dick told me that Chris Cunningham, editor of Sea Kayaker Magazine wanted to do an article for Sea Kayaker on it. Chris requested that Dick make sure that no pictures of it get out on the Internet before his magazine article came out.  Well, too bad, because the cat's already out of the bag!  Remember you saw it here first! These are some of the pics that Stephen S published recently on his awesome SSTIKS gallery.

 

Great job, Lodro!  I heard she's a pretty sweet ride too!

 

 

 

 

 

 

Announcing: Qajaqs for everyone!

OK, I’ll admit that once in a while I fight a strong urge to go shopping for a fiberglass production boat.  After all, who would not be attracted to the idea of having spacious dry compartments, a comfortable molded seat and drop down skeg?  I’ve even gone so far as to call dealers and demo a few.  But something always stops me -- my inability to decide on a color scheme, lack of storage space in my garage, the thought that I would only really use it for a week or two touring in the summer (not to mention the price)!  Ultimately though it’s probably the thought that, given a little work and a year or two, I could make that elusive "perfect kayak" myself out of wood!  (Well, maybe once I finish that last project that's been sitting neglected in the shop.)

There have been exciting developments recently in the qajaq building world, just in time for the New Year.  If you were thinking of finally building that kayak in 2008, you have a couple more options to look into. 

First of all, Lodro Dawa of Monkcraft kayaks now has a custom Greenland kayak kit for sale.  Without having to equip your own woodshop, you too can make a skin-on-frame kayak.  According to the Monk:

"The kit comes with everything you need, including a fully illustrated and very detailed assembly manual and technical support if you get stuck. To complete the kayak little woodworking is required. The gunwales are milled to shape, mortised, marked and pre-drilled for the deck beams and ready to go. The deck beams are cut and ready to install, as are the pre-bent ribs. The stems, coaming and all others parts are ready for assembly. Once you have completed the frame, you’ll skin it, dye and shrink the skin, apply the polyurethane and fit out the kayak. This kit is designed so that you can built it in your living room if necessary and will take only 30 to 40 hours to complete. Only simple ordinary tools are required."

Price is $985.  Just like the custom-built kayaks, each kit is customized according to the paddler's  dimensions and skill level.

Secondly, if you are still insist on building your own kayak from scratch, Wolfgang Brinck has published instructions for building a Greenland Kayak on the Instructables website.  By the way, if you like building, Instructables is a cool site to surf on.  You can find instructions on how to make a little matchstick rocket or bathroom slippers with LED lights on the tips, for instance.   Brinck’s method of building is a modification of the HC Petersen and Svend Ulstrup methods.  The instructions are long and quite detailed, so I haven’t had a chance to read through it completely.  Looks like a nice boat though.

Kayaks of Norway

I'd like to interrupt my cruising travelogue to offer congratulations to Jørn Thomas Holth of Norway, who sent this picture of his recently completed Greenland kayak, built using a few of my recommendations. He says it is just what he was looking for in a rolling kayak.  I love the black skin and uncluttered deck.  He has called it The Pirate  :-)

I've finally uploaded the plans for the South Greenland kayak, actually an East Greenland kayak, surveyed by Howard Chapelle in 1948, and featured in Adney and Chapelle's book, The Bark Canoes and Skin Boats of North America, figure 208.  *Whew*, that's a long description.  You know, the plans for The Jewel.  For lack of a better name (and I think there are others out there) I've just started calling the original kayak C208.  Harvey Golden said that he surveyed the same kayak also.  He might even have included it in his book Kayaks of Greenland.  I'll have to take a closer look through his book to see if I can find it (honestly, I haven't read it yet).

The plans I've uploaded for C208 consist of the lines drawing in jpg (30 in x 8 in).  I've also included four pdf files which are the same lines drawing divided into letter-size pages.  The idea is that you can print them out on regular paper and piece them together using the reference marks I've included on the drawing.

The files can be found on my file-sharing page here.

The plans for C208 can also be ordered directly from The Smithsonian.  It may take a couple months and the address and price may change (I think the address on their web site is incorrect).  Here is a copy of my order from last summer:

Ship Plans
Smithsonian Institution
National Museum of American History
Behring Center
P.O. Box 37012
AHB-5301/MRC 628
Washington, D.C. 20013-7012

To Whom It May Concern:

Please accept my order for Plan no. BC-89 (South Greenland Kayak) on page 43 of the Ship Plan List, Maritime Collection, to be shipped to my home address above.

I have enclosed a check payment of $15.

Thank you.

Another Comparison

Here is another comparison of The Jewel with the Chapelle drawing [click on the photo for a bigger picture].  It looks like in my version the sheer is a little more pronounced and I may also have added more rocker, but not much.  I can always say that Chapelle got it wrong because the museum piece was hogged from being stored upright for so long.  Who really knows?