Play Washington on an Archipelago map, and use the State Property civ*. The more coast tiles under your control, the more you dominate. EVERY water resource can support a worthwhile city, even the icebound, and there will be little competition for the spots.
* - he's Fin, which is 3 commerce/tile; he's Org, so Lighthouses and, more important, Courthouses, are cheap, which gets each city into the black faster, and State Property negates distance cost, the primary component on the negative side of the ledger of a far-flung empire, while making workshops very viable, providing much needed hammers to make up for the hammerless coastal squares.
BTW, there's a BIG difference between coast and ocean, especially for Fin civs. Probably better to run a specialist than to work ocean.