I'm not quite sure what is going to happen to the Seeker of Silvered Loot Commendation, but in case anyone wants to get their 500 chests done in Arena before the change I thought I'd share what I did to get 200 chest digs in one day of grind.
You can do this Solo and most importantly don't worry about winning. Winning isn't the objective and wastes time that could be spent on digging chest. First take a good look at your map to get an idea where chests are. The time you spend looking at your map is time lost for digging. Try and get a general idea where everything is so you can run to it after a dig and look at your map along the way to get a more precise idea. Shoot over to an island and tap and go. Don't worry about your ship. Don't waste time fighting; scuttle if you get stuck in a fight. It's not a bad idea to scuttle your boat just as you set foot on the island, but only need to do if it looks like it might get you caught in a fight cause it's nice to have a boat to head to the next island. Don't bother fully digging up chests, that wastes time and bringing it back to your boat is a bigger waste of time. Just tap it and go to the next dig site. This is all about getting digs as fast as possible. You only need to hit it once to get a dig for the count. Once you're done digging all the chest head to the next island and do the same thing. Do your best to clear all islands of digs so more maps will spawn and you can do even more digging. If all goes well and with a bit of luck you can get around 20-30 digs a game. In around 4-5 games you could get over 100 digs. That's around 3 hours of gameplay. You could easily get your 500 chest digs before the next update if you're willing to put the time and effort.
