Light vs Heavy, Soft vs Hard, For Safety

For those unfamiliar with UK Television, the third photo down in post 15, is Ellie Harrison, a presenter on the BBC TV programme Countryfile.

 

I'm in love, I think she's looking at me.

 

LOL SamSam!

Speaking of bags, I use one in my Kayak, used it in the canoe, not so much as to keeping water out, as they do, but my canoe will sink, I think, so I tie it in.

I'd like, as I mentioned, to deck part of it. If waters get rough I'd like to reach for a large cover, like a spray cover. I might get into class II waters, probably not III unless weather changes on a large river which could get rough. And I'm not wanting a small canoe or craft either.

Now, if I can just talk those paddlers to go with me I wouldn't have to worry about anything, or care to worry.....

 

Which way did the occupants go? Follow the arrow!

 

Looks like the creeks around here, but that was kinda my point, light, inflatable, it wouldn't wrap around a tree like that aluminum, it would peel off on one side or the other eventually, just hang on. Looks like they lost it before they hit that tree. Flood waters around here move at 30 to 40 mph taking a car or truck to the same fate, inflatables survive. Looks like they didn't ride the center of that flood very well too. Go with the flow.....

 

Interesting discussion that I only just found. Designing or just specifying scantlings is often a bit of a quandary. Design the Herreshoff method or the belt and suspenders method? Then there is what the builder of the boat may think is necessary.

Very often we are saved by the simple fact that when a boat part is made stiff enough to handle the job without excessive deflection (a relatively simple calculation), other strength requirements are well exceeded. Puncture resistance is an exception to that and just about anything we might reasonably do can be punctured by dragons that lurk in the water.

Fortunately, designers of most of the the small boats for the home building masses are pretty well guided by established scantling rules such as those published by Gerr and others. That lots of boats that are built lighter than most of us consider proper survive for long periods without damage is due to the fact that dragons in the water are not all that common in most areas.

A few years ago a friend asked me to repair a hole in the bottom of his old Chris Craft V8 powered runabout that had an encounter with a day mark that was knocked down just under the surface in the channel. He hit it on the end and punctured the bottom amidships with a hole the size of my head. Barely managed to get it ashore with help from construction crew that happened to be nearby. What I found was a 3/8" fir ply bottom that was very much weakened by years of oil and gas from the motor. I would have thought 3'8" ply was a bit thin even if in good condition for a utility type runabout with this power and this stuff could be torn apart with my hands. Of course any reasonable scantling would probably suffer the same fate in this case but it is a good example of looking at what happens in long service in such an application. Our wonder goo would have prevented most of the degradation though.

I agree completely with those who advocate a sheath on the inside of areas subject to penetration by hard objects as better than just making the skin thicker. Deflection absorbs lots of impact as proven by auto engineers in collision testing.

I have a friend who has paddled the entire Mississippi in a canoe and the most danger was from people, not stuff.

 

Tom, thanks for the input. By "sheath" I'm reading that as placing the waterproof sheeting between the frame/stringers and the scantlings. I can see a simple lap sided boat with glued laps, sealed and painted with just a few inches of relief at each lap using 1/4" ply. Seems that each plank could be glued so that there could be complete coverage but allowing the relief overhang on the lower lap, (nails covered and gooped) edges sealed and painted.

I'm looking for plans but I doubt this would be incorporated into any set of basic plans....don't know.

As to your friend and his encounter with people, was that with bad boaters, the drunks or were there more aggressive acts?

Yes, what I'm trying to do is to get a safe boat but a quick build without fiberglass, a beefed up skin on frame. I can also see this being done and then at a later date some sanding and glass could be added. Flotation as well as a tube or collar could be used as well.

 

An encounter with some good old boys who had a bit too much to drink and looking for a patsy. Nothing came of it but was probably frightening to someone alone. We have all probably had that happen at one time or another.

The interior sheath was like that advocated by PAR earlier. A high modulus strength membrane that is put in simple tension by an impact on the outside of the panel.

 

Ancient seafarers stiched wood together to build boats. Vikings, Eskimos, Amerinds, Egyptians, ect. They used organic materials.

You could probably stich your lapstrakes with Spectra and never come apart.

http://goodwinds.com/line-winders/braided-spectra-line.html

 

Yes, somewhat in that direction Yobarnacle, looking at old plans various woods were selected to ensure strength of scantlings in vulnerable areas and built lighter in others, also in balancing the craft. Interior building in fixtures also adding to the overall structure not just adding a berth or galley cabinet. I also saw where muslin was used between planking in years past.

Bolts and screws were relied on with solid wood, now plywood and adhesives have replaced much of that I found. Bolts don't really like plywood or it may be the other way around. Glass changed much of all this too.

Slab sides of 1/8" ply are common on small craft I see, 1/4" and solid framing would make me sleep better aboard and seems weight goes to size or displacement.

I suppose what is needed it a design to go further. A freighter canoe was mentioned but that's not cast in stone.

Bolger seems to have a hold on me due to simplicity, again not in stone.

A sharpie, dory with more V, but really I'd like to incorporate the heavy gauge rip-stop PVC as a membrane or covering. Perhaps a wood bottom and taking the PVC above the water line and wrapped cabin would make it water tight, I'd think if well framed above it could be self righting too. The light vs heavy aspect.

I doubt I'm too concerned about the drunken bubbas along any river, Betsey can go on inland trips without concerns and she is really loud, I've met them before too without her along. But I do think it's a shame when people feel the need for such company, it's the way society is going, at least here. Ignore and keep moving usually works. That's off topic here.

What ever the boat design is, it's for camp cruising, sail and low power, less than 15hp we'll say. Thinking along the lines of a SOF backed up with some ply inside....???

 

I understand the desire to build it yourself. I'm bitten. I'm just starting out with old hulls of a design I respect.

The polyethelene sea kayaks have much to recommend in terms of lightness, ruggedness, and seaworthyness.