MRE Boat at Oroville Spillway

I’ve now had the chance to test the MRE Boat 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.

I’m still not sure how comfortable the boat will be to paddle. I need to add a seat and some thigh padding before I can be sure, but I still think the deck may be too high at the cockpit. I may have to lower the shear near the middle of the boat, which will have consequences with regards to storage and camping in the cockpit.

I’ve also been thinking about how to reduce the build time. I may change the build process. By doing most of the fabrication ahead of time and shipping the boat as an un-assembled kit I should be able to get the assembly time to a day or two. I’m also thinking about building the boat in sections that bolt together in even less time. Why not go with a skin on frame boat like the folbot, you ask? Too easy, and I want something more substantial than fabric under me when I get to alligator country.

By the way, the photo above was taken from the Thermalito Diversion Pool below Oroville Dam. I grew up less than 20 miles from Oroville and never knew the diversion pool existed until about a week ago when I did a Google search for free kayak launch sites at Lake Oroville. I paddled from the lower end of the diversion pool up to the base of Oroville Dam and back on a Saturday afternoon and I was the only one on the water. It is a beautiful place to paddle  and I highly recommend it if you happen to be in the area. It’s in the City of Oroville, but in a secluded gorge that is full of wildlife. I saw a bald eagle, foxes, loons, all kinds of wildlife.

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.

I wanted something that would carry a payload of about 300 lbs. and with a cockpit that I could sleep in. The boat I designed is just over 15′ long – the maximum length using two standard sheets of plywood scarfed together. It has a maximum beam of 18″ at the keel and 24″ at the shear. The cockpit is 6′ long. There are four bulkheads and four watertight compartments – two with access ports for storage. The boat has a flat bottom for ease of construction and flared sides to add some stability. The prismatic coefficient is 0.57 and the theoretical maximum hull speed is 5.2 kts. The boat is symmetrical about two axes, so four half side panels can be cut at once, two half bottom panels are cut together, and the same for the deck panels and bulkheads. The boat is similar to a kayak, with a deck and narrow beam, but it has tall sides like a canoe.

The build plan was to use 3 sheets of 1/8″ luan plywood (one sheet for the four half side panels, one sheet for the bottom, and one for the deck), 1/4 sheet of 1/4″ plywood for the bulkheads, 5 yards of 6 oz. fiberglass cloth, and a gallon of polyester resin. I did use the cheap luan plywood from Home Depot ($10 a sheet), but i used epoxy instead of polyester because I find it to be less gruesome to work with. The epoxy and a few odds and ends (two inspection ports and wood for the shear clamp and deck beams for the most part) blew the budget. Waiting for epoxy to dry blew the schedule.

Assembled Hull

The hull went together quickly. I cut all the panels and scarfed them together in just a couple of hours. I also epoxied the two sides together at the bow and stern at the same time. That way, I could just pop the bottom between the sides, temporarily duct tape everything together, fillet and tape the joint, put a coat of epoxy on the interior, attach the bulkheads, and the hull would be almost done. That worked according to plan and only took a few hours, but then I had to wait for the epoxy to dry.

The next day I fiberglassed the exterior of the hull, and then had to wait a day for the epoxy to dry. Then one of the shear clamps broke and I had to wait another day for the epoxy on the repair to dry. After six days the boat was finally complete.

MRE Boat Ready to Test

It Floats!

Front View (or Rear View)

I’ve taken the boat out once for a short paddle on the Oakland Estuary. With no load besides me it is less stable than I would like it to be. The sides are high (11″ at the cockpit) so I need to sit on a 2″ pad in order to paddle comfortably, which adds to the stability problem. I hope 100 lbs of gear will make it less tippy.

It tracks really well and it seems to move along at a good clip with little effort. I didn’t have my GPS so I don’t know how fast it is. I was worried about the strength of the hull (the Home Depot luan plywood is really crappy – I wouldn’t use it again)but it is really solid.

So at this point I am cautiously optimistic that I could build a kayak on-site for a Mississippi River trip. I think I could get the build time to four days, and the cost would be about $300. If the stability improves when the boat is loaded, the design will be ideal. Otherwise I’ll add some beam and perhaps a v-hull to improve stability.

I’ll be at Maker Faire Bay Area in San Mateo on May 21-22. I won’t have a complete shelter due to the limited space and time available for disassembly, but I will have sample parts to show how the system works. I hope to see you there.

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.

The building was easy to assemble. I first built the floor the same size as the exterior dimensions of the building.

Bottom Sill

Next, the bottom sill was attached to the floor. The bottom sill adds horizontal strength to the walls, attaches the walls to the floor, and diverts any water that gets between the panels to the outside of the building. The corners were caulked to make them watertight.

Wall Assembly

Starting at one corner, the wall panels are placed on the bottom sill and a ‘c’ clip is slid over the flanges of adjacent panels, connecting them together. A sheet metal screw on each side of the inside of the panels attaches the wall panel to the bottom sill. Half panels or quarter panel are used where there will be windows.

More Wall Assembly

Continue placing wall panels until the walls are complete, bracing where necessary. Once the wall are complete, ‘Z’ flashing is screwed to the top of the walls.

Roof Beams

The roof beams are placed on the ‘Z’ flashing, bolted together, and screwed to the ‘Z’ flashing. The front roof beam is 2″ x 2″ and the rear roof beam is 2″ x 6″ to give the roof a slight pitch. There will be a small porch in front of the door and the roof will  extend over it.

Roof Assembly

Next, the roof panels are placed on the roof and screwed to the roof beams using an angle bracket between adjacent panels. The adjacent panels are then clipped together with a ‘C’ clip. The ‘C’ clip makes an extremely rigid joint and seals the joint from the top so water cannot penetrate.

Ceiling

The ceiling is exposed galvanized metal with seams every 16″. It could be painted or covered with acoustic tiles or some such thing. I like the natural galvanized metal.

Once the windows and doors are installed, the building is complete. If one wants to run electrical wiring in the walls, the interior wall panels are removable and there are pre-punched holes at the top and bottom of the panels for wiring. Interior walls can be built and plumbing added if required.

Front View

Rear View

Side View

Other Side View - no door yet

Interior

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.

The panels are joined together using ‘c’ clips that slide over the flanges of adjacent panels.

'C' Clip

One 4′ x 8′ sheet of galvanized steel makes exactly two wall panels and two ‘c’ clips with zero waste. One 4′ x 8′ sheet of EPS foam makes exactly three foam inserts for wall panels, and three interior panels are cut from each 4′ x 8′ panel with zero waste.

Roof Panel

The second type of panel is the roof panel. It is the same shape as the wall panel, but it is 3-1/4″ thick and 10′ long. There are no variations of the roof panels. The roof panels have the ‘c’ clip on the outside and the flat galvanized side is the inside. This makes the joint water-tight. A 4′ x 10′ sheet of galvanized steel makes exactly two roof panels with zero waste. The roof panels are insulated with 2″ thick EPS foam and the foam is covered with a 26 gage galvanized panel.

Wall Panels in Compact Truck

All of the wall panels for a 120 square foot building will fit in a compact truck level with the top of the bed before the foam and interior panel are added. When fully assembled they fill the back of a full-sized pickup to the top of the bed. Everything for 120 square foot building will fit in a full-sized pickup to about the level of the top of the cab. The components for sixteen 120 square foot buildings will fit in a 40′ container.

Bottom Sill

There are a few auxiliary components needed to assemble a building. The bottom sill comes in 10′ lengths and attaches the wall panels to the deck or foundation upon which the building is constructed. It also drains any water that gets between the wall panels to the outside of the building.

2″ ‘z’ flashing is used under the roof beams and around window openings. A 2″ x 2″ roof beam in 10′ sections is used atop one long wall, and a 2″ x 6″ roof beam in 10′ sections is used on the other long wall. Small ‘L’ brackets along each roof beam hold the roof panels on.

Everything was designed to assemble only with clips, but it became too complicated. The floor to wall attachments and roof to wall attachments now use sheet metal screws. This means you really need an electric drill to assemble the building, so I missed on that goal. I was also off on the cost. I estimate my cost in materials and labor to be close to $5,000. However, I bought everything at retail prices and only manufactured components for one building. I think the $2,000 price could be achievable with wholesale materials and a better manufacturing process.

It took me about 15 hours to assemble the prototype building, but I believe an 8 hour build time is possible once the kinks are worked out.

Overall I’m pretty happy with the way the project turned out. The building was easy to put together and everything fit quite well. The building is very solid.

Panels clipped together are like an I-beam

When the panels are clipped together the joint is like an I-beam, so every 16″ it’s as if there is an I-beam running vertically up the wall and across the roof. The top and bottom sill and roof beam stiffen the walls in the horizontal direction. The resulting structure is rock solid.

I can’t tell yet how effective the insulation is. The walls have about an R-9 and the roof R-12.

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.

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.

Fiberglassing bulkheads & decks

Front hatch and bulkhead

Aft deck

Pilothouse fixture

Foam shell ready for fiberglass

Pilothouse draped in fiberglass & ready for epoxy

Pilothouse on the hull - looks hideous

I fiberglassed the bottom first...

Another shot from the front. You can see the bow filled with foam.

Then I turned the hull to one side and glassed it. Repeated for other side.

Here I am cutting the slot for the bowboard.

Another shot of the bowboard slot, and you can see the inside of the hull completely fiberglassed.

Fiberglassing the inside of the bowboard slot.

To fiberglass inside the bowboard slot, I built a blank the size of the inside of the slot. I covered it in aluminum foil and waxed the foil so the epoxy would not stick to it. Then I wrapped several layers of fiberglass soaked in epoxy around the blank and jammed it into the slot (making sure it was positioned correctly). The fiberglass extended past the slot a few inches at the top, bottom, and front of the bow, and I wrapped these edges around the bow. Later I will reinforce this area with more fiberglass.

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.

Architect Michael Reynolds of Earthship Biotecture, at center, worked with 40 local Haitians in Port-au-Prince to construct an earthship out of used tires and bottles salvaged from the area.

There is an article about architect Michael Reynolds and an earthship he built in Haiti in a recent Wall Street Journal blog. The earthship seems well suited to Haiti (good insulation, sturdy, use materials that can be  found locally for free), and when finished they can be quite aesthetically pleasing.