I have both inflatable kayaks and stand-up paddleboards. I like them both as does my dog Moose. I use my Tower SUPs more than my tandem IKs; they are smaller, lighter, and just easier to lug around. The IKs are more stable in whitewater. I've only used them in very low Class 2 rapids. They are great, but since I bought tandems (for why else than so Moose could come with me!) they are heavier and longer.
My grouchy friend in Portland wrote me recently:
"Hey- what kind of pump should I get for my IK? Foot pump or NRS Wonder Pump 6?"
And my much less grouchy friends in Denver asked what kind of pumps I'd recommend for their new SUP: "You are correct. We need to get an electric pump. Took me longer than I wanted to pump this sucker up in 100 degree temperature. I need to find the message you sent with your recommendations."
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IKs need to be inflated to about 2 psi, whereas SUPs should be inflated up to 6 to 10 psi. This is a pretty big difference.
From the Aire inflatable kayak manual:
Top off each chamber in the same pattern. If you hear a humming sound in the floor valve, it’s the pressure release indicating the floor has reached maximum pressure (2.5 psi) and you can stop pumping. For the other chambers, using your thumb you should be able to depress about ½” from the top center of the tube.
For IKs, here's what I recommend these days:
I think the best all around (for IK) is a foot pump.
However, I am always confused as the best Bravo foot pump to get and how many frigging models there are.
I have lately been using a Bravo! 9 Double Chamber High Volume and High Pressure 14.5 PSI Foot Pump to inflate my inflatable kayak (an NRS Outlaw II) so that they are semi-rigid. This is overkill for an IK, which only needs 2.5 psi.
Here's an inexpensive Bravo foot pump that will work for a while:
https://www.westmarine.com/buy/west-marine--bravo-7-foot-pump--10967644
Bravo 7 foot pump only $20, that's a deal.
I'll then pull out the awesome K-100 pump to finish off the pumping task. The K-100 pump is just great. I bought this pump with the internal check valve so air won't go back into the pump. The internal check valve only cost $2.95 more, so it's a no-brainer to order it along with the pump.
I also bought a K100 hand pump:
https://www.nrs.com/product/1714/k-pump-100
I love this thing. It is great. The Bravo foot pump will get you just about the whole way you need (for IKs, not SUPs). I use K100 hand pump to top off the IKs (and to pump my SUP sup to 6 to 10 psi).
To get the IK inflated initially, rather than a foot pump, I'll often use an electric high-volume inflator as I describe below.
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To inflate a SUP (6 to 10 psi):
Any of these will work to get your SUP up to 1-2 psi (initial high-volume inflation):
Bravo foot pump
Ryobi high volume inflator with battery or dual inflator
any electric inflating pump, like this one or the $11 one below:
https://smile.amazon.com/Electric-Portable-Quick-Fill-Inflator-Inflatable/dp/B074NZY3SQ/ref=sr_1_5?dchild=1&keywords=air+pump&qid=1598152824&sr=8-5
Here's an inexpensive pump that would work for initial high volume inflation:
https://slickdeals.net/f/14288885-outdoormaster-op420-0-64-ps-electric-air-mattress-pump-11-19-amazon?src=SiteSearchV2_SearchBarV2Algo1
$11.19 @ Amazon with code W76U5FDK
I have also used this pump, which works great off my car battery:
Sevylor SUP and Water Sport Electric Pump, 12V, 15-PSI
https://www.walmart.com/ip/Sevylor-SUP-and-Water-Sport-Electric-Pump-12V-15-PSI/35395714
(No longer at Amazon, probably temporary)
Electric air pumps work great when you are putting stuff together in your garage, but when you get to a parking lot, it's hot, you have a dog that is in a rush and wants to run around, there are lots of people, then having to hook an electric pump up to your car and inflate the SUP is just not advisable or workable. Usually, I get my SUP initially inflated in my garage up to 1 to 2 psi -- I get it mostly filled up but nowhere near full with an electric inflator.
I've been using a Ryobi high volume inflator or dual inflator for the initial high-volume inflation:
https://www.ryobitools.com/products/details/one-18v-high-volume-power-inflator
https://www.homedepot.com/p/RYOBI-18-Volt-ONE-Dual-Function-Inflator-Deflator-Tool-Only-P747/308746324