Below are patterns for making spray decks like the one pictured above, designed to fit Small, Medium, and Large DIY Packrafts (and V2 plans).
This is a permanently-attached “whitewater” style deck that uses a separate spray skirt.
The cockpit opening (i.e. the hole where you sit) shown below is small compared to some kayak cockpit openings and, depending on your femur length, you may prefer a larger opening… I suggest you experiment with a mock-up before deciding how big to make your opening.
You’ll need at least 1 m of fabric for the Small and Medium size decks, and 2 m for the Large. I recommend using 210D fabric. You will also need one aluminum tent pole; there are cheap, good quality tent poles available on Amazon and elsewhere online, and I recommend purchasing one about 3 m (10′) long – that way you will have spare segments in case you break some while bending them. (The tent pole’s diameter is not important.)
I made the above spray deck with the TPU side of the fabric facing down, but you could make yours with the TPU facing up so you can heat-seal gear attachment points to the top of the deck – you will just need to attach the deck to the packraft with additional strips of fabric around its perimeter instead of sealing it directly to the packraft’s tubes.
Eventually I will post plans for a spray skirt and make a video showing how I put everything together. Here are some dimensions to get you started:
Note: All measurements are in millimetres. Spray decks are symmetrical, so only half the deck is shown.
Small Size spray deck dimensions:
Medium Size spray deck dimensions:
Large Size spray deck dimensions:
This is a cross-section showing the detail of how the cockpit coaming sleeve is attached to the spray deck:
The tent pole sleeve is made from a strip of fabric 5 cm wide and long enough to wrap all the way around the cockpit opening. The joining sleeve is made from a strip of fabric 4 cm wide, the same length. Where the two ends of the coaming meet, they are spliced together with a small strip of fabric.
A hole is cut in the sleeve (in an area that will be covered by the spray skirt) for the tent pole to slide in and out.