"This is the front side of the ship."

Translation: Kesy lōgro naejon issa.

[Amadeo472845]

Why can't i use Kesor instead of Kesy

[xPsGoDWh]

Because "this" is the subject of the sentence and its own element. "Kesor" can only be used in conjuction with a noun - "this [noun]", basically - not in a "this is" construction. Also, it's only for aquatic nouns, and "naejon" is terrestrial.