The DIY Packraft spray decks use flexible plastic tubing to stiffen the rim that the elastic spray skirt fits over (the coaming), and several customers have said that the tubing I supplied with their kit is too flimsy to secure their spray skirts. I was kind of scratching my head about this because it works fine for me, but it turns out that although I purchased two batches of the same type of tubing from the same manufacturer, the second batch was more flexible than the first. I talked to the manufacturer about it and the reason is still a mystery, but clearly I need to find a different tubing for the kits. I’m sorry I didn’t catch this sooner.
So far it seems like 1/2″ PEX-B pipe works quite well as a coaming stiffener.
PEX (cross-linked polyethylene) has been used to make flexible plumbing pipes in Europe for decades and it has spread around the world to become the standard waterline pipe used in modern building construction, so it’s cheap and available in most hardware stores and plumbing supply shops. PEX-B, the medium stiffness PEX, is the most common and it’s the type I recommend. You won’t find PEX-A (more flexible) or PEX-C (stiffer) as an option in most stores. If the tubing is just advertised as “PEX” then it’s probably PEX-B.
A 10′ length of PEX costs less than $5, so if the coaming stiffener I supplied in your kit isn’t doing its job, I’d prefer to offer a partial refund or a credit whenever possible, because shipping replacement parts to you would cost much more than buying the parts locally.
If you’re looking for a replacement stiffener for your spray deck, please purchase a 10′ length of 1/2″ PEX-B and a straight coupler (external links are for example only). Cut the pipe to length using the same procedure recommended in the spray deck kit instructions.
The color of the PEX doesn’t matter, and all PEX-B should be manufactured to the same standard, so the source shouldn’t matter either. Note that although white PEX and PVC pipes look similar, they are not the same. If in doubt, just look at the code printed on the side of the tubing and somewhere it should say something like “PEX-B” or “PEXb”, or maybe just “PEX”.
If plumbing is measured in metric units where you live, choose a PEX-B pipe/tubing with an inside diameter close to 13 mm (finger width) and a wall thickness of about 2 mm. Other diameters might work – I recommend the 1/2″ (12.7mm) size because that is the size I am familiar with. You’ll need a length of about 2.5 m. If you’re unsure what to buy, send me a message and I’ll try to help.
If the tubing I supplied in your spray deck kit is too flexible and you’d like a partial refund or a credit, just send me an email.
Thanks for your understanding!
4 Comments
Patrick · August 14, 2023 at 3:42 pm
Thanks for addressing this issue, Matt. I found that with 1/2″ PEX-b for combing, the spray skirt stays fairly well attached to the spray deck through class III. However, it’s still far from dry in that boat. As my body rotates while paddling through whitewater, the waist shock-cord tends to drop down my waist until it sits quite low. Water then pools on the skirt and slowly drips through my shirt and into the cockpit. After running my local 2 mile stretch of whitewater, I had 50-70lbs of water in the boat. So while it won’t negate the need for a drysuit in cold conditions, it does at least prevent having to get out & dump the boat after every rapid. I think my next adjustment will be adding shoulder straps to the skirt to keep it higher on my waist. After that, I may look at aquasealing the holes along the deck where the tube-fabric-joining strips prevent a seal, as you suggest in the tutorial.
Uncle Fred · September 19, 2023 at 9:16 pm
I found the same issue with the skirt. You can correct this by adding adjustable straps to your skirt. These will prevent the skirt from gradually shifting down. I also found I needed to add additional fabric panels to offer more ‘give’ to the skirt, allowing me to shift around in the boat a bit more without putting tension on the skirt.
Matt · July 14, 2023 at 11:10 am
is there a way to tell between the two batches? I got a kit six months ago and haven’t put it together yet. Should I just to put it together with Pex out of an abundance of caution?
Matt (Admin) · July 14, 2023 at 1:35 pm
I don’t think there’s an easy way to tell, but the stiffener is something that you insert and remove each time you use the packraft, so you don’t really need to worry about it beforehand – if it’s not stiff enough to keep the skirt on when you get to that point then you can replace it.