Tested: Tyre pump adaptor for inflatable kayaks

See also
Pumps

You may have seen these bayonet/car tyre adapters on eBay in recent months (left). The bayonet end clamps into your IK’s raft valve (won’t work on Boston valves). The other end is a regular Schrader valve like on your car/bike wheel. Attach that to your 12-volt Halfords tyre compressor and you can inflate your IK from your car battery. No more of that effortful, back-breaking pumping!

Me, I’ve never seen the value of electric pumps for IKs. (Packrafts are another matter). You can only use them near a power source, or the rechargeable battery will run out. And how hard and slow is inflating an IK with a good barrel pump anyway? As IKs catch on with more mainstream recreational users (whose cheap boats may come with a rubbish pump), some find manual pumping too tiring. What is this world coming too?!

The difference between tyres and IKs:
• a car tyre is a low-volume, high-pressure vessel (~30 litres @ ~30psi)
• an IK has high volume but runs low pressure (3 chambers of 50–160 litres @ ~3psi). Drop-stitch has less volume but runs much more pressure.

That’s up to five times more volume in an IK, but at a tenth of the pressure. I would guess the swept volume of my better-than-average car pump (left) is 3–5cc. My Bravo RED 4 barrel pump is 2 x 2000cc (it pumps on the up and the down strokes).
Even if my 12-volt compressor whizzes along at 1001rpm, it will still take a long, long time to fill a 160-litre IK floor. But for a fiver, I thought I’d prove myself right.

The Test
The easiest way was to pump up my Seawave’s floor to the point the PRV purged at about 3psi. The actual psi is immaterial but it’s consistent.

No surprise: it took less than a minute to pump up the 160-litre floor with the barrel. With my car tyre pump it took over 7 minutes.
And if you want say 4psi in the sides, or a 10psi drop-stitch boat, the duration of the tyre pump (or effort with the barrel pump) rises exponentially. It will take forever with the car pump adapter and I think the tyre pump would auto shut-off or burn-out before it reached anywhere near 10psi.

Just a tenner on amazon

I looked into rechargable or D-cell battery or mains/car electric pumps like above. They go on amazon from just £9.99, or even less for mains only or 4 x D-cell battery. These may be great for pool toys, air beds and other low-pressure items like slackrafts which just need a shape, not rigidity.
The Pumteck (left; £15) claims an obscure pressure rating of 4.5 kPa which sounds impressive but translates to just 0.65 psi or 0.045 bar. That is slackraft pressure; there is no worthwhile IK that runs such a low psi.

All these pumps do is save you the initial pumping which merely takes time (< 5 mins), not effort. The rechargeable ones will be spent in 10 minutes and then need hours of recharging. For a typical 3-psi IK you’ll still need some sort of manual pump to top off to full pressure; even more so a higher pressure DS IK.
If your back can’t handle a barrel pump (taller pumps work better for taller folk), consider a Bravo foot pump, but with any dropstitch IK there is no getting round the need for a high-pressure barrel pump or a very expensive SUP electric pump.

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.