Guppy trailer, part 4: assembled

At last, after a month of fabrication, I was able to assemble the parts on the morning of June 23, 2013. Strangely, it began to rain that day and drizzled off and on for the next two days–something I have never seen in California in June! But I had varnished so many of the components that it did not matter, and I was thankful for the cool weather. Sophia took the photographs, and Gabriel helped with the assembly:





Above, I am bolting down the left-side wall to the deck. The deck is a simple 4X8 sheet of 1/2″ plywood. I didn’t use the flatbed of the trailer itself as the deck because it is a mix of steel at the edges and rough pine planks across the middle–in fact the manufacturer would not give me shop drawings of it, and I had to design the cabin while I was waiting for the flatbed to be built and delivered to the dealer. So while I was assembling the walls and ribcage, I had the 1/2″ cabin-deck sitting on wooden crates. You can see one of the crates in this image, marked “computer.” By holding the deck up, I was able to install bolts from below into the L-brackets at the base of each wall-stud.


I attached the rear bulkhead and the left wall to the deck; then I could attach the ribcage. Here you see the “Pony” 90-degree vises in action. A few other things to note in this image: 1) Two weeks earlier I had scabbed the curved pieces together into five ‘flying’ ribs as well as top-rails attached to the sidewalls. To make sure they matched, I clamped them all together and belt-sanded them to a smooth match. Before unclamping the ribs, I marked across them every 4″. This greatly simplified the process of assembling the ribcage (see Part 3). You can see a few of the marks in the foreground. 2) You can also see the roughness of the rib-assembly. To use wood efficiently, the nose-curve had to be compiled out of short arcs of wood, glued together. On the left side of the picture you can see where the upper “back” segment overlaps with the upper “nose” segment and the lower “nose” segment of each rib. 3) Just beyond the ribcage is our neighbor’s car. Yes, I did indeed build this trailer in a parking-space.


With the ribcage and one side-wall installed, I then glued and screwed the first layer of 1/8″ plywood on the inside of the ribcage. This image clearly shows how the cabin-structure is ‘up on blocks’ for the moment, while I counter-sink and tighten the bolts that hold the ribs and wall studs to the deck. I have also cut and framed in the left side window openings, and the upper vent-openings. I could not wait any longer, because the next step was to install the rigid foam insulation into the wall-voids.


This view from the right-front shows how the structure is coming together. I installed the ceiling/nose layers of plywood before bolting on the right sidewall. That sequence was driven by the need to get big sheets inside before the openings were too small to admit them.

This turned out to be a problem because the stressed-skin ribcage flexed open a bit, and it was very difficult to get the right-side wall to align as I installed it. In retrospect, I would prefer to bend the interior sheets of plywood to the ribcage *after* both walls are installed. But how? The trapdoor in the rear bulkhead (see the image above) points toward a different solution. Rather than a partial-width trapdoor, you could make a full-width door–meaning that the bulkhead would not come down to the deck. Then you could slip full-length sheets of plywood into the interior space from the back, and bend them into place on a completed wall-and-rib frame.


I got the right-side wall installed. Then Lizzie helped me roll out sheets of thin foam underlayment before removing the wood blocks and dropping the cabin onto the flatbed. The thin foam underlayment comes from IKEA; it is what you lay down on a floor before installing their masonite faux hardwood floors. We had a roll of the foam left over after we installed such a floor in our living room.

Here you can also see the insulation I am cutting and jamming into the wall-cavities. Again, unexpectedly cool look! Crinkly yet shiny, like a 1960s space-capsule. I cut the foam with a kitchen knife. A word of advice: if you can’t stand the sound of squeaking styrofoam, this is a difficult step. Lizzie and the kids literally had to stay out of earshot during this entire process.


Next step: laminating the outer skin onto the ribcage. My neighbor Keith loaned me a set of cargo-straps, which I used to apply even pressure across the ply skin as I glued/screwed it down to the ribs. Other people, with more time, more clamps, and a garage, might be able to do this without screws. But one of the defining features of this project was that I had to get it built as quickly as possible.


View with the left side skin installed. Since I was using stainless-steel screws, I decided to just glue-screw the sidewalls and leave the screw heads exposed. The white vinyl tape on the flatbed marks the position of each wall-stud so I could align my screws.


I began the major assembly on June 23. By July 3, I had the structure insulated, had the outer skin installed, had it bolted to the flatbed using long, squared-off U-bolts. No windows, and the back end remained completely unfinished. The last thing I did before we towed the Guppy for 1,000 miles was install the door.

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