The names of all the ships in One Piece are suffixed with Go in Japanese. For example, Going Merry Go, Thousand Sunny Go, Moby Dick Go. However, the English version drops the Go suffix. This suggested it might be a honorific used to address a ship, but I couldn't find any source that says "Go" is a honorific.
There's also no mention of Go on the Japanese ship-naming conventions page on Wikipedia, and I couldn't find anything like this in any other place either.
I don't recall this being explained in the manga. Is there any explanation for this use of "Go", with a reliable source for reference?