Here a video with an example. I can get four different routes to about the same place and only one of them is effecient in any manner. The other three are WAY extra.
#Sea navigation gone wild
tribal stone
cloud cape
This happens on land too, around western navern steppe
cloud cape
It's not as bad as that, but it's still pretty bad
carmine fossil
On land it "makes sense" because they want you to avoid running into mobs that can potentially kill your horse. On lower seas, there's no reason to go 284 nautical miles north to avoid a baby whale which has zero agro. Or a hekaru which also, has no aggro. You can afk fish beside them 
lucid tiger
I wish this issue was not multiple years old
Some of the results I found with a 5 second google search
tribal stone
Sea navigation gone wild
fresh jetty
Coming back from hackoven with some extra loop backs
carmine fossil
Maybe it's because I was... facing the wrong direction?!
carmine fossil
