But it can be converted to what's basically water bc all of the properties of shinsoo are determined by it's "flow" (Source: Blogpost)
Basically, imagine being able to turn soda into lightning based on how you stir it.
Bam copied and uses moves from Hansung-style, which is water based. (This was confirmed recently given that Hansung was capable of holding back and manipulating the Cat Tower's water before and during his fight with Haratcha)
(Waves of Peacock Wings, Maelstrom, Dragon's Breath, Rapid-Fire Shinsoo Cannon, and Endless Sky are all Hansung-style skills Bam has used before/during Last Station- he uses it almost as often as Jinsung-style, meaning it'd definitely be used against Luffy)
Yeah this is a stomp