kayak dinghy under 5kg

I'm thinking quickly. But maybe carbon tubing isn't the best profile for this design. Stringers with a cosmic elliptical I-beam cross-section, carbon band frames, custom elements at the bow and stern, a carbon openwork seat, and airtight cargo hatches.
The skin could be made of heavier, welded TPU for good sealing and damage resistance. Additionally, pneumatic buoyancy and stiffening chambers wouldn't be a bad idea. CAD drawings and model printing make the whole process much easier.

 

Based on this thread, the Inuit people kayak build concept with welding TPU sounds good to me. I'm obsessed with the weight of boats, but practicality is also important to me.
For example, the ability to fold them. I have to used an old USSR-made inflatable kayak. It was pretty terrible for paddling, but after adding a plywood bottom floor, handling improved much.

 

I'm also weight obsessed ;-) After Leastie Beastie I gave a lot of thought to the issue but nothing jumped out as being worth the effort. A lot of new tech has arrived since then. In todays world I might look into a framework of higher pressure tubing as a starting point but there's a limit to new projects at my age.

 

That's really a clever idea about putting in a floor and folding up, makes it into a small, fast row RIB concept, curious how much did it weigh with the floor in?

Yes , ultralight weight and unique designs able to reach Waters that no other craft can reach has been the goal for me. I have several different sizes of boats, the ones I use most often are the one man battery powered ultralights. They allow me to go places where other boats don't go or can't go, which gets me away from the noisy, crowded public boat ramps and launch sites.. Plus easy Portage with a back strap around Rapids while inflated, because of 10 zippered gear holding pockets that are built in. Allows me to launch/go anywhere I can walk or crawl, ignoring kayak/ pack boat boulder/rock barriers, which would require unload/carry/reload with other designs. The 5 ft/ 1.8 m boat weighs about 5 kg or 11 lb and around 30 lb fully loaded with batteries, trailing shaft motor, snacks, 1 L water, fishing gear, inflation gear, tools and spare parts, etc. I travel four times a year by Airline to explore rivers and small Lakes in addition to local use; Two of these ultralights will fit in an Airline carry-on case. Design allows for instant Mount / dismount/standup in shallow water usually done around 50x per trip, and the inflatable seat & back angle are adjustable over a large range producing ergonomic comfort while sitting dry 6 in above the water surface. They are known as kick boats because fishermen use them with fins. I use a motor and trailing prop which allows me to Cruise the flats down to 4 in/10 cm deep; 2 hand paddles for emergency backup. Here's a link to a similar set up in action, except that a trailing shaft motor is used.

 

There's risk with any high pressure stuff when exposed to serious sun rays.Anyway saftey valve is always possible .I'heard from some sport store guy that inflatable tents doesn't last long . There are many difficult to glue places. Maybe kind of inner tube is the soultion when we think about h.p. but again , tyre have setup difficult to copy in the tent or kayak .

 

I was about 5' piece of below 3/8" thick plywood . 8mm as I remeber .I rounded edges to avoid egde punctures . Local pressure of my *** was dissipated around .

 

You've found your niche.