In modern Chinese, 轮船 (lúnchuán) is used to refer specifically to large, motorized sea-faring vessels. Its usage is generally neutral and descriptive.
Travel and Tourism: You'll frequently encounter this term when discussing travel by sea. Taking a cruise or a long-distance ferry is often described as 坐轮船 (zuò lúnchuán), “to ride a ship.”
Formal and Written Contexts: It's more common in writing, news reports, and formal announcements than in casual, everyday speech. For example, a news report might state, “一艘货运轮船抵达了港口” (Yī sōu huòyùn lúnchuán dǐdále gǎngkǒu - A cargo ship has arrived at the port).
Distinguishing Size: In conversation, if you see a small fishing boat and a massive container ship, you would call the small one a 船 (chuán) and the large one a 轮船 (lúnchuán) to emphasize its size and mechanical nature.