In general, if a seaplane can fly X distance, can it travel that distance on the surface of the water as if it was a boat or ship? In other words, this would be equivalent to taxiing all the way to a destination. E.g. if a seaplane has the range to fly from New York to Amsterdam, could a pilot simply choose to taxi all the way across the Atlantic Ocean and casually slip into the harbor?
If this is not generally possible, what rules define what sort of sea journeys a seaplane could undertake? Is there a coefficient of inefficiency (e.g. if a seaplane can fly X miles, it can taxi X/2 miles due to increased drag from the water)? Are the vast majority of seaplanes not set up to handle the stresses of a long-distance sea trip, making them likely to result in a shipwreck (er, seaplanewreck)?
This is not the same question as Is it possible to sail a seaplane? . That question is asking about sailing a seaplane using sails without any engines. I am asking about "sailing" a seaplane using the engines and whatever other tools are available for taxiing.
This question is about the physics and engineering issues - not about licensing. I am fully aware that taxiing a seaplane across a body of water might make the trip fall under boat regulations and require a sea captain's license, but I'm not asking about that.