Whitewater decking

I'm preparing for the decking for a Briggs style Grand Canyon Dory.   Do all of the tops of the frames (vertical ribs) need to be cut so the decking sits on top of them?  Or, do they poke through and continue to the sheer rail as on an un-decked boat?  Thanks for any insight - Joe

Views: 1764

▶ Reply to This

Replies to This Discussion

Permalink Reply by Jeremy Christensen on February 14, 2010 at 9:38pm
I've had some practice with on-stream repairs. My very first trip I repaired a small crack in the bottom while laid over at Steer Ridge. My first trip through Westwater I repaired a major chine blowout while snacking on lunch at Hades Bar. My approach to repairs has changed a lot over the years, and after reading a post of yours about repair kits...I keep it simple, no more huge repair kit. Some 5 min epoxy, sawdust, and gorilla tape was all it took to repair the gaping chine hole in Westwater. The more extensive the on-river repair, the more work it is to fix it up right once you get home. For the Grand I'll probably add some bailing wire, window screen, wood screws and some plywood scraps just in case. Hoping for uneventful, planning for carnage. We'll have 4 wood boats and 4 different builders on our trip, so I hope we'll be ready for any situation that arises.
Permalink Reply by Brad Dimock on February 14, 2010 at 9:46pm
Our Grand Canyon river patch of choice is duct-tape for minor wounds. For major ones we make a plaster of QuickPoxy and window screen on a piece of waxed paper. Slap it on and go. It is the rare and mighty wreck that needs much more than that. But we have a few of those too! For those, wood scraps and drywall screws augment the quickpoxy plasters and duct-tape. As Jeremy says, the less you do on the river, the less work it is to undo back in the shop.

Jeremy--what was the sawdust for?
Permalink Reply by Jeremy Christensen on February 14, 2010 at 9:56pm
re: sawdust - filler for the epoxy, to pack the grapefruit-sized hole in the chine from that bastard of a rock lurking at Hades Bar. It was a major pain in the butt to dig out in the shop to make the permenant repair though. I like the window screen/epoxy plaster method. I think you said to lay out the window screen on wax paper, dump on the epoxy, drink a beer while it kicks, then slap it on, right? simple. This comes off once you get it in the shop? How does the final repair come together?

Sorry to hijack this thread....
Permalink Reply by Brad Dimock on February 14, 2010 at 10:20pm
Yikes!

Yeah, the epoxy plaster is super-simple and comes off quick with a light grinder. Your guess as to how it works is basically correct, except there's no time for drinking a beer mid process--the quickpoxy goes off real fast. Spread the epoxy out fairly thin on the screen, which is laying on the wax paper. As soon as it is spread out, slap it on. I'd advise drinking a beer beforehand, and perhaps one after.

Final repair varies, depending on magnitude of damage. For lightly fractured plywood, I've been known to dry it out in the shop, shoot the fractures full of epoxy with a hypodemic nerdle, then sandwich the thing flat between two board covered with waxed paper. (Squeeze it flat with a couple through-bolts and fill the boltholes later.) This is called a spooge patch--basically you're turning plywood into particle board. When there's too much damage for a spooge patch, we usually scarf out the bad place and scarf in new plywood.

Attached is a little series of images of Andy Hutchinson and I in my boatshop doing a one-day repair on an old Briggs boat that had an encounter with the fang rocks at 232. They are: 14) cutting out the damage; 31) Grinding in an 8:1 scarf to side and rub rail; 37) Fixing cracked ribs (lunch break); 45) WESTing in the new wood; and 51) Screwing on the splints. The fairing was done later.
Attachments:
Permalink Reply by Brad Dimock on February 14, 2010 at 10:23pm
I might ad, this is one of the last Briggs boat I know that still has its rub rails. We've found them to be horrific rot traps and removed them on nearly all the boats. With the recent invention of fenders on trailers, I'm not sure why anyone still puts the rub rails on.
Attachments:
Permalink Reply by Kelly Neu on February 14, 2010 at 10:32pm
Brad, Do you put anything on the chine? I've seen rubber strips which seem like they might displace some impact force. What are trailer fenders? -Sounds usefull.
Permalink Reply by Brad Dimock on February 14, 2010 at 10:55pm
Oh, on the video that Randy has attached to the website, an oldtimer describes inventing the rub rails because the old boat trailers had no fenders and the tires, mud, and rock would damage the boat sides--so they stuck that extra strip of wood on. So now that trailers are required by law to have fenders, why the rub rails? We found so much rot behind them on the old Briggs boats that it was appalling.

As the ribs and inside chine were incrementally removed from a lot of the boats down here over the years, the inner chine log and outer chine strip were replaced by fiberglass inside and out. This left no outer chine, and some folks felt it made their boats handle funny. It also left a very vulnerable edge where the fiberglass would chafe and leak--and here comes the damned rot again. So various folks started gluing on a full or partial outer chine to protect the glass edge and add stability. The newest/coolest of these outer chines is the one you mention--a thick strip of black rubber. It works pretty well at protecting the edge, stabilizing the boat, and does a bit to protect from impact--although major impact still blasts right through the hull. But even then, it's easy to peel back the rubber, do a quick patch, glue the rubber back on and be on your way.

One refinement of all this came in the high water of the mid 1980s, when we started gluing outer chines on for big water stability. But one of our ski racer boatmen decided that, like a racing ski, it was best to "detune" the far ends--that is to say, take the outer chine strip off the far ends, so the bow and stern wouldn't grab weird currents. Seems to work. So you'll see a lot of Grand Canyon boats that have the rubber strip only on the central 12' or so of the boat.

1/2" x 1-1/2" x 16' strips are about $12 each from Nott Atwater in Spokane. Minimum order $100.
Permalink Reply by Jeremy Christensen on February 15, 2010 at 8:33am
question about outer chine strips - my boat is S&G, and I've run it for 3 seasons without outer chine strips. How much stability do they really add? Is it noticeable? Would it be worth the trouble of adding them to my boat?

I became friends with Renny Russell while I was building my boat after going to a reading of his new book (Rock Me on the Water - amazing) where he showed a slideshow, from which one picture really stuck out. It was of a dude whose name escapes me, standing there holding a huge piece of the hull of his dory - "Woodenshoe", a boat that I think Andy H. built. I guess he wrecked it in the rock garden below Crystal. So there he is, holding this big chunk of dory that is conspicuously unattached to the boat from whence it came, and he has this huge smile on his face, no worries. They put the boat back together and finished the trip, and as far as I know it's still on the water. From what I was told though, once the boat was put back together, the name had been shortened to "Woodenhoe."

A lot of people seem to have hangups about wood boats, that they are inherently fragile like an antique vase. I have adopted the casual attitude of build it, break it, fix it and get on with it. Still hate the hear the crunch, but every repair presents a new opportunity for problem solving and ingenuity.
Permalink Reply by Brad Dimock on February 15, 2010 at 8:59am
To be honest, I cannot say for sure that the exterior chine makes a lot of difference. Several of the full-time guides I was running with in the big water (30,000-60,000) swore it was a huge improvement, so I went along with it--didn't want to miss out! Maybe I'm a hack, but I am not sure I could tell the difference. But if the majority of opinions means anything, it helps, especially in very high flows.

The main reason you might consider it is just to protect that vulnerable fiberglass edge from abrasion and the consequent seepage, which leads to the inevitable rot.

Wrecks: I tore the entire front eight feet off my boat one time, and I wish I could say I smiled throughout the epic wreck/repair process, but I frowned a lot. Ran the right side of Lava Falls with the repaired boat two days later though. And still run that same boat.

I'm kind of like those crazed EMT paramedics that love a good wreck. I LOVE righting upside-down boats, extricating stuck boats, but most of all, fixing wrecked wooden boats. I'm just a little cheerier when they are someone else's.
Permalink Reply by Randy Dersham on February 15, 2010 at 9:11am
Great comment about ingenuity Jeremy. I completely agree.

It's interesting to see the chine issue come up again. The chine isn't going to add "stability" to the boat. Like a good ski edge it will increase your ability to track so the boat will hold a line better and can "cut an edge" to ferry giving the rower greater control.

In shallow rocky water like we have in the West this added control is important as we dodge rocks, on big powerful, but non white, water the chine is not as useful and the chine dip in the big eddies seems to out weigh the need to ferry. Now I know of a third Colorado River option that is obviously made to cushion collisions.

Brad's description of a chine batten of rubber is very interesting and a great example of how a specific water type will cause design change. It seems in BIG water with decked boats you are more worried about the high speed collision with rocks. Good solution. On our fast shallow water with open boats sticky is very bad. Sticking on a rock allows the boat to tip to the water. We have about one second to get right or slide off of the rock or the boat will begin to fill with water. Anything that helps us slide off of a rock is a good thing.

Rubber would be very bad for us because of how sticky it is. Two solutions have come up for the West Coast boats. The best looking and best performing is stainless steel half round which is also usually put in the center twelve feet of the boat. The slickest and lest expensive is a strip of UHMW plastic.
Permalink Reply by twoblacklabs on August 2, 2010 at 5:32pm
LOL. I am one of those crazy Paramedics. Became by virtue of being a whitewater kayaker in Jackson, Wy. Spent so much time on the river and was always drawn to the boaters that needed help. Finally decided I needed to help folks on a more professional level. And yes, I really love a good wreck.
Permalink Reply by Kelly Neu on February 18, 2010 at 11:56pm
Which density do you go with? Nott Atwater has a few options; basically Soft, Medium, Hard.

Do you put a bevel on those strips? If so, do I need to hire a magician to pull it off?

And Joe, sorry for the off track thread post.

RSS

© 2024   Created by Randy Dersham.   Powered by

Badges  |  Report an Issue  |  Terms of Service