Correct spelling, explanation: yacht is an English noun that originates from the Dutch language. Its previous form was jacht. Before spelling a word, one should always look at its etymology. Yatch is clearly a mistake and the only correct form is yacht.

Definition of yacht:
verb, race, or cruise in a yacht
Last year we went yachting and it didn’t come out very well.
I really want to try yachting. Maybe next year I’ll manage to do it.

Incorrect spelling, explanation: if the word yacht were spelled yatch, the pronunciation would be quite different. It’s also important to look at its origin – it comes from the Dutch form jacht. Yatch is just a mistake and it shouldn’t be written down like this. Yacht is the one and only correct spelling.

Incorrect spelling