Mjmd PM'ed me asking if I had conceded and I said yes, so I think the game will end. Just waiting on Mjmd or lurkers to confirm it.
Some final stats:
Fleet 1 killed 2 cities and was close to killing the third. They were left low health waiting to heal. Fleet 3 could have joined them to help.
Fleet 2 was two turns away from landing, but Amica had been trading well against our ships in the last few turns over there, so we did not have a free reign over the coast.
Fleet 3 changed ships at GKC's ex-capital and was waiting for upgrades, though would have been forced to be used for defense with Amica breaking through.
The plan as a whole I did for fun, but I do actually think it's viable. Amica was just too much ahead with no other threats.
Vikings imo are a top tier civ in a water map. Free navigation is just good for all ships, and amphibious CR units are great for attacks from the sea.
We did not really get to surprise attack in this game since both attacks were blindingly obvious from the game state.
My plan was also to threaten cities in long term. You can really stretch the enemy forces by targeting many coastal cities, and with 5 move you can rotate quickly.
GG's all, and well played Amica.