TLDR: Get a dedicated SUP pump. I own one of these compressors for airing up Jeep tires, and gave it a shot with inflating a SUP. https://www.amazon.com/Smittybilt-2780-2-54-Universal-Compressor/dp/B004K296N6 Rough math here, a 345L SUP converts to 12cu ft, and that compressor flows 2.54CFM, which is considerably higher than the DeWalt which I also own. I found it took roughly 20min to fully inflate the SUP. It works, but it sucks in comparison to a SUP pump where you can set the pressure and be done in 10min. These put of considerable amounts of heat too, which I can’t imagine is great for your SUP.