Lightweight Kayak

Ultralight kayak on the beach at Alameda.
Ultralight kayak on the beach at Alameda.

My first kayak was a heavy rotomolded sit on top. I had a lot of fun with it, but it was heavy and slow. The decked canoe/outrigger sailing canoe I built is lighter and faster, but it is too long to haul around all the time and has a large cockpit that isn’t good for rough water. So I built this lightweight kayak for everyday use. It is 12′ long, 22″ wide, and weighs 24 lbs.

I designed the kayak using Hulls and AutoCAD. I printed out full sized patterns and traced them onto the panels. the kayak is symmetrical front to back so I cut out four identical half side panels at one time, and two identical half bottom panels and joined them together at the center. I used that crappy 1/8″ plywood from Home Depot again.

The hull is assembled using duct tape to temporarily hold it together.
The hull is assembled using duct tape to temporarily hold it together.

Once the side panels and bottom panel were epoxied together, the hull was ready to assemble. I temporarily taped everything together with duct tape, then filleted all the joints with thickened epoxy and covered the fillet with a strip of fiberglass.

The assembled hull after the tape has been removed.
The assembled hull after the tape has been removed.

Before the epoxy was set, the bulkheads were tacked in place and alignment was checked. Everything was allowed to cure overnight, and the next day the bulkheads were filleted and taped in place and the bulkheads and inside of the hull was sealed with epoxy. I also fiberglass the floor of the cockpit and a few inches up the sides to add strength in this area.

Fiberglassing the exterior of the hull.
Fiberglassing the exterior of the hull.

Once the inside of the hull was sealed, the kayak was turned over and the exterior of the hull was fiberglassed. I ran the fiberglass past the ends of the bow and stern, then trimmed it even with the plywood once the epoxy gelled. The next day I sanded the ends, then wrapped two strips of fiberglass over each end, covered with waxed paper, and clamped boards over the waxed paper. No more sanding on the bow and stern were needed – I hate sanding.

Installing the external sheer clamp.
Installing the external sheer clamp.

Next the external sheer clamp was installed with thickened epoxy. I used an external sheer clamp so the fiberglass on the deck could run over the sheer clamp and be trimmed even with its bottom edge. This way there was very little sanding required, and I hate sanding.

Attaching the deck.
Attaching the deck.

Next, the deck was attached. Since there wasn’t a deck beam the deck was not cut to shape – it was left rectangular so there would be a constant curve along the length of the deck. The deck would tend to have flat spots at the ends if this wasn’t done. The milk jugs full of water tied across the ends also helped to maintain the curve. The underside of the deck was sealed with epoxy, and it was bonded to the hull with thickened epoxy. It was temporarily tacked in place while the epoxy set.

The deck is trimmed even with the sheer clamps.
The deck is trimmed even with the sheer clamps.

After the epoxy cured the kayak was turned over and the deck was trimmed even with the sheer clamps with a hand saw. Then the kayak was turned right side up and the edge of the deck was rounded with a plane and rough sandpaper. The deck was fiberglassed.

Installing the cockpit coaming.
Installing the cockpit coaming.

Next the hatches and cockpit were cut out and the cockpit coaming was installed. The kayak was painted. The hatchcovers and deck lines were attached and kayak was ready to paddle.

Painted, Hatched, and Coamed.
Painted, Hatched, and Coamed.
Ready to paddle.
Ready to paddle.

Outrigger Sailing Canoe Model A

The Huck Finn Canoe Is Now An Outrigger Sailing Canoe
The Huck Finn Canoe Is Now An Outrigger Sailing Canoe

Not long after my last post over three years ago, a family member had some serious health issues. My priorities changed and I quit updating this blog. Now I have time continue with it (I hope). I have continued to work on some projects as time has allowed. I’ve continued using the canoe I built three years ago. It’s a good canoe – stable, tracks well, and easy to paddle. I paddled it from the aquatic center in Oakland across the Bay to AT&T Park in San Francisco and back two years ago. It performed well, although I had a wild ride on the way back with 25 kph winds and steep wind waves. I broke a paddle but made it – I was relieved to get back to the calm water in the estuary.

Not long after that I became interested in outrigger sailing canoes and decided to put outriggers and a sail on the canoe. I had some old 2″ aluminum tubing that I used for the crossbeams. I bought some 4″ PVC drain pipe at home depot and capped the ends with foam. I shaped a leeboard and a rudder out of some 1″ fir, got my old windsurfing mast and sail out of the basement,  lashed it all together, and went sailing.

It’s not the best sailboat I’ve ever been on, but it works. It takes about an hour to unload everything and get it assembled. It doesn’t sail very close to the wind – maybe 70 degrees. I usually have to paddle to complete a turn. But it is a fun little boat and it got me more excited about outrigger sailing canoes. Even though it has many design flaws it’s a quick little boat. Unfortunately I completely lost interest in the sailing canoe I started four years ago – it was too slow, so I gave it away. Once one has experienced an outrigger sailing canoe it is hard to go back to slow boats.

Huck Finn Canoe Update

MRE Boat at Oroville Spillway

I’ve now had the chance to test the Huck Finn Canoe several times, and I was definitely wrong about the stability. The boat is very stable. In fact, when I tried to tip over to see if I could re-enter from the water, I had a hard time getting it to tip. One has to roll to about 80 degrees before it goes over – I think this is because of the high, flat sides.

I was also concerned about being able to get back in the boat after a wet exit, especially because of the deck height. This turned out not to be a problem either. The boat was practically dry inside when I turned it upright, and I was able to jump back in on the first try with no difficulty.

I also checked the speed of the boat with my GPS. If I paddle pretty hard I can reach 4.6 kts. Paddling at a leisurely pace I can maintain 3.5 kts. This was in flat water with a light breeze. We haven’t had much wind lately so I do not know how the wind will affect performance.

Continue reading

Huck Finn Canoe

MRE Boat Design

I’ve always wanted to do the Huck Finn thing and float down the Mississippi River. If I were smart I would fly to Minneapolis, buy a kayak, paddle to New Orleans, sell the kayak, and fly home. But let’s face it, I’m not that smart, so instead I ask myself what would Huck Finn do? Of course we know the answer – Huck would hang out on an island until a raft floated by, jump on, and be on his way. Since I live nowhere near the Mississippi River this will not work for me, and anyway it is doubtful that derelict rafts are still as plentiful on the Mississippi as they were in Huck’s day.

I like designing and building things, so I decided to try to design a boat that I could build in two days with indigenous materials sustainably sourced near the headwaters of the Mississippi (you know – Home Depot in Minneapolis) and a few hand tools. I failed miserably – it took me six days and $230 in materials to build the prototype – but it is actually a pretty nice boat. Continue reading

Assembly of the Basic Shelter Prototype

Here is a photo of the almost complete prototype.

Front view of the Basic Shelter

The building is 8′ x 15′. It has an 8′ ceiling. There are three large windows in front and two smaller windows in back. The exterior can be painted or left natural.

Interior Wall

The interior walls are pre-finished. For the prototype I used 1/8″ mahogany type plywood that came as packaging for sheet metal. It actually doesn’t look too bad. The metal strips are the clips used to assemble the building. Continue reading

My Solution – Basic Shelter Panel System

Wall Panel

My solution is to use two basic panels as the building blocks to assemble a building. The wall panel is 16″ wide, 2″ thick, and 8′ long. It is formed from 22 gage into a ‘c’ shaped panel. 1″ holes are pre-punched in the flange near the top and bottom of the panel to run electrical wiring if desired.

Assembled Wall Panel

The inside of the wall panel has a 3/8″ air space (thermal break), 1-1/2″ EPS foam insulation, and a pre-finished 1/8″ interior wall panel. There are also half panels (4′ long) and quarter panels (2′ long) that are used to create openings for windows. Continue reading

Design Brief for the Basic Shelter Panel System

The primary goal of the Basic Shelter Kit was to design the minimum number of components that could be used to build a variety of shelters for disaster relief operations. With this in mind I developed a list of attributes to design towards.

  1. Minimize the number of primary components. Ideally there should be three or fewer ‘building blocks’, and 10 or fewer auxiliary components.
  2. None of the components should weigh more than 30 lbs. One person should be able to carry and install all components.
  3. No components will be longer than 10′ or wider than 4′.
  4. The components for an entire building of approximately 120 square feet should fit in a standard sized pickup.
  5. The components for at least 12 buildings of approximately 120 square feet should fit in a standard 40′ container.
  6. The buildings must withstand 100 mph winds and moderate earthquakes.
  7. The roof must support 2′ of snow.
  8. The building must be watertight, insulated, and wind-tight.
  9. Few or no tools should be required to assemble a building, and no power tools should be required.
  10. One person should be able to assemble a building of 120 square feet in one day.
  11. There should be zero waste produced during the manufacturing and assembly of a building.
  12. All materials must be recyclable and should have a high content of recycled material.
  13. All components must be reusable. A building should disassemble quickly for shipping and  installation at a new location.
  14. The same basic components must be capable of being used to build structures of various sizes and configurations.
  15. All of the components for a 120 square foot building should cost less than $2,000 to manufacture.

Progress on Micro-cruising Sailing Kayak

As usual with boat work, my progress has been slow. I thought I would be getting close to finished by this time, but I’m not even close. I have continued to tweak the design. I have moved the paddling position back into the pilothouse – decided shifting weight from position to position would not be practical. Had to redesign the pilothouse to accommodate paddling. I’m also working on the sailing rig – still not happy with it.

I’ve added bulkheads to the hull, front and rear decks, and framed the front hatch where my bike goes. I have built the pilothouse shell, but it is hideously ugly. I’m going to try to improve it, but function has to take precedence. I have to be able to paddle comfortably, so I may end up with one butt ugly boat. See the photos after the jump. Continue reading

I Start My Boat

First, I build a mold.

Assembling the Boat Mold

Next, I join together my EPS sheets. My boat is 12 feet long, but my EPS sheets are 8 feet long. Therefore I butt my sheets together and bond them with expanding polyurethane foam.

EPS Sheets Butted Together for Bonding
Panels are Bonded
Joint after Trimming

I designed the hull in Hulls, a free program for designing hulls. I then transfered the hull and panel layouts into AutoCAD where I completed the more detailed design drawings. The panel layouts were plotted full sized, glued to 1/8″ masonite, and patterns were cut from the masonite. I traced the panels to the EPS sheets from the patterns.

Tracing the Hull Panels

I cut the hull panels using a sharp steak knife.

Cutting the Hull Panels

The side panels are attached to the mold and bonded with expanding foam.

Side Panels are Attached to the Mold

Thickened epoxy is applied to the top edges of the  side panels (which are actually the bottom edges since the hull is being built upside down) and the bottom panel is bonded to the side panels. The jugs of water are used to bend the bottom panel to shape. Drywall screws temporarily hold the bottom panel in place while the epoxy sets.

The Bottom Panel is Attached the the Mold

Once the epoxy sets I shape the hull with a Surform and sanding block. The bottom panel is trimmed flush with the side panels, and all edges are given a slight radius so the fiberglass will drape over the hull properly.

Shaping the Hull - Stern

The photo below shows how much rocker the hull has.

Shaping the Hull - Bow

I also added a bit of V to the bow and stern.

Stern V
Bow V

The hull is ready for fiberglass. I used 4 layers of 6 oz cloth on the bottom and 3 layers on the sides. Getting all of that cloth to drape properly over the hull took 2 days.

Fiberglass is Draped Over the Hull
It Took 2 Days to Get the Fiberglass To Drape Nicely Over the Hull

It took another day to wet out the cloth with epoxy.

Wetting Out the Cloth
Wetting Out the Cloth Took Almost a Full Day

Three hot coats were needed to fill out the weave and get a glossy finish for sanding. The hull was then flipped over and the mold was removed.

The Hull is Flipped and the Mold is Removed

Here I am pouring some expanding foam into the bow.

Pouring Expanding foam in the Bow

Now I am ready to fiberglass the inside of the hull.