@sinjaming Search up any scumlords PvP youtube you'll find plenty. Can I describe all of them? No, because I do not use them and as such I do not necessarily know how they work. I will list a few to give you examples though. Also, can we stop focusing on the "double gunning" part of what I said because I clearly mentioned a key distinction: The PvP Culture. Double gunning is merely a result because the exploits that come with it and the cancerous abusive metas (whether abuse of glitches or abuse of Rares unintended implementations)
There's a ladder glitch where some how players are able to spam grab the ladder going up and down and shooting someone with their eye of reach while not being able to be hit back (or else it is very difficult to do so).
There is silent ladder grabbing, people are able to grab your ladder and board without you hearing the sound that rare intended for you to hear. I've seen people shoot cannons without the recoil animation thereby not blocking their view for the next shot and potentially firing faster (though I'm not sure about the faster shooting part).
There was a glitch to multiply the amount of fruit you were able to buy by having each of your crew buy the fruit supplies at the exact same time and thereby placing 25 (for a gally) pineapples into your fruit barrel (this was patched but abused none-the-less)
Some parts of the boat and be attacked or shot through (whether its intentional or not is beyond me but as far as I'm concerned most developers would want their objects to function as solid objects)
I was shown someone doing the shovel animation faster than me and was told you can bucket faster as well (they didn't tell me how, however) perhaps this is part of animation cancelling which also is a problem that benefits double gunning.
I'm not gonna go around and do my homework to try and prove my point: There's constantly a meta of people trying to break and abuse the game and that meta is prevalent among the top of the PvP community and it spreads downwards to those who even want to attempt to compete against them. You can suggest there are people that do this in other games but I've found it more prevalent in SOT, simply because of the lack of attention the PvP balance has been given by Rare and their inability or indifference to controlling their communities culture and direction
As I've stated in a previous comment, Rare could also be at fault for their lack of awareness or simply their incompetence in balance. What I mean by this is: something could clearly be unbalanced (as PvP is as a whole, not specifically to do with double gunning or swords, but overall) and Rare could simply not know about it. This is why blunderbombs existed for as long as they did and only got nerfed after it took the same culture of people to spam and create a toxic and unfun PvP environment for Rare to realize "this is not what we intended for this item to do".