Hi Jeremy, @akjw7
In general, a good place to start is in piece #5 (either Left or Right) near the seam with piece #4 and on the down-slope on the outside of the tube. If you’re measuring during construction, that’s about 38 cm (15″) up from the corner between pieces 4 and 5 on the outside of the tube, and about 7 cm (2.75″) away from the seam.
I recommend using the same installation method as for the Boston valve (detailed here), where the valve flange is sandwiched with glue between two layers of fabric that are heat-sealed together.
If you wait to install the top-up valve until after your packraft is otherwise finished you will be able to paddle it first and practice twisting your body around to make sure that that location will work for you. People have different body sizes and degrees of flexibility, so the ideal placement may not be the same for everyone. If you find it too awkward to twist your body around to reach that spot, an alternative placement might be on the inside of the cockpit near where your face ends up when you bend forward (i.e. close to your knee, but not where it will rub).
If you like, you can use field repair tape or something similar to hold the valve in place while you experiment with different locations on the water.
Wherever you put it, remember to make sure your arm/elbow won’t hit the valve while you’re paddling!
