Perhaps it had gold filigree around decorative scrollwork on the windowsills and doorframes, and a nice camouflage pattern on the rest of the ship… Or maybe it was just a large, wooden ship covered inside and out with pitch. Keep in mind, if it still exists somewhere, it has been around for a few thousand years (what would the weather have done to the pitch? I don’t know!). God certainly didn’t think it was necessary to give us this information in His written word (and I’m not aware of any “traditional” teaching on this topic). Fortunately, my faith is not dependent upon this information, or even finding the remains of the Ark.
I agree with LilyM that speculation on this topic does not show a souls love for God. God Himself tells us in His word, “For the rest, brethren, whatsoever things are true, whatsoever modest, whatsoever just, whatsoever holy, whatsoever lovely, whatsoever of good fame, if there be any virtue, if any praise of discipline, think on these things.” (Phi 4:8 DRA).