Had a conversation the other day, with a new owner of one of my sof kayaks, and he was bragging about how well it was holding up, considering he was bouncing and scooting it over rocks, going down the raptds at his local river ... not something I had really foreseen as an activity for an almost 18 foot baidarka, but, what the heck, it is skinned with 12 oz ballistic cordura, and I can always throw a few more coats of wb lpu on after the season!
which brought up the idea... why not design a WW sof? I'm planning on two chine stringers, to help with shock tolerance, probably use ash or bamboo for those two, 3/4 X 3/4, with WRC for the rest, then see where I need extra rub strips on the outside as I go along.
Well there is an advantage to poly for WW boats, can take an amazing amount of punishment and still float. My antique WW boat is a great example, don't think there is a square inch of it that's not covered with layers of scratches and gouges
It's been done on squirt boat in composites (the layup schedule of them is a good idea of the stresses involved if you're interested) , I suppose it could be done SOF but would require either a very flexible frame or a seriously robust one that's rigid enough to absorb the necessary punishment and survive. Hitting a rock at 20 mph over and over tests the durablity of most structures
I agree with poly for most serious WW, and only have to turn over my own poly kayak to see why
On the other hand, most of the rivers nearby are class III and below, and some are stretching the class to seem more exciting.
I'm planning on flexibility of ash and bamboo to absorb most of the shock, with HDPE rub strips to ease the scratch occurance, though I don't worry too much about the durability of 12 oz ballistic nylon, and at the 11 foot length, re-skinning every couple of years isn't too bad.
I can tell you 7 oz wont do. Shredded mine on a shoal with obviously some extremely sharp somethings in there. My buddies brand new poly boat was even damaged. 12 oz is darn tough though.
My concern would be getting the frame pinned against and rock and wrapping around it with me inside. I think that is the biggest risk in moving water with these boats. I think a side impact in swifter water would snap the stringers like twigs.
I toyed with the idea for making one for some of the creeks around here. Lots of shallow shoals with an occasional rapid but nothing big at all. But I decided against it. Just not my cup of tea.
I decided to build the canoe instead so I fish from it. I will carry it around any rapids of line it over.
Most of the rapids on the east coast are pretty tame, in my opinion, so I wasn't worried about wrwpping rocks, with the exception of one creek, which I'd be a little nervous even in my plastic boat. I've never run it, just fished most of it, but I know there are some sections that could be challenging.
We have a creek around here that I plan on fishing from the canoe I am working on. It really is no big deal, just a few shallow spots that make shoals at lower waters. Two rapids, one is class one and the other is a class two because of the 2' water fall. I have run them in a cheap fiberglass canoe. no big deal. I probably will not run the drop in my new canoe.
So my buddy ios going and taking some other freind and they borrow dads canoe. When the get to the Class 2, those in dads canoe wrapped that boat AROUND the ONLY boulder in the current. Luckily no was pinned or drowned or was even scratched up. But this is a mild stream with one hazard and they caught it.
I am sure you know the risks, but that changed my thinking on white water and gave me a much higher respect for it!
AS scary as it is to admit it, my first whitewater trip was 50 years ago next month ! I respect it, but don't ever plan on shunning it... at least until I grow up, and I don't plan on doing that any time soon !!!!!!!!!!
OK, I've decided to post some pics of this build, and have just started with it. I appologize for the picture quality, grabbed the wrong camera when I was leaving for the shop this morning, but these will do for now. When I laid out the frames, I wanted to leave them a little beefy, since there will be some rough contact occasionally, but, looking at the frame that will be at calf level, I realized the space was a bit tight, and there was a potential chafing situation on my calves, which I wanted to avoid, so I looked around the spare parts bin, and found some leftover masics that were already laminated into a decent curve, so I butchered them into strips I could laminate onto the frames, making the beefiness horizontal, rather than cutting into leg space.
I'm also using ash stringers for the keelson and first chine, and spanish cedar for the second chine. they're a bit heavy, but they're only 11' long, so I wasn't too worried about the extra weight.
It's been a while, I got hung up skinning and painting a couple of other kayaks, then Grandpa duties called, and of course paddling is much more fun than taking pictures of what I'm working on, etc.... anyway, here's some shot of the modifications for the whitewater frame, that I felt were neccessary for my own peace of mind.
Attachments
added some bent stock for a "shock bumper to the stem and stern. you can also see that the frames are radically cut back from the stringers, to avoid trapping the skin between a rock and a frame
I drilled the keelson for the lashing to avoid a chafe spot on the bottom, but I do that anyway, the keelson and first stringer are ash, and the second stringer is spanish cedar.. heavier than WRC, but much stronger
Btw, my first SOF when I was like 10 (many years ago) had steam bent oak ribs and oak stringers, wasn't all that heavy but was quite flexible and thus damage resistant.
I've been a bit lazy this year, with the sewing and researching the hull finish material, which will be Grizzly Grip truck bed liner, since it is available in 24 colors.
this isn't exactly the type of white water I had in mind when I started the WW design, even though it IS white (for now) and it is basically water. I think I have a few days left to finish it before launch time, though.
That was technically a 24" snowfall, with blizzrd conditions, which means some very interesting drifts... we had 34" on our front porch, jamming the front door, so I had to open the garage door so I could shovel my way out to the street... that horrendous mound is the car, with a 36" drift on top
... not something I had really foreseen as an activity for an almost 18 foot baidarka, but, what the heck, it is skinned with 12 oz ballistic cordura, and I can always throw a few more coats of wb lpu on after the season!
!!!!!!!!!!