To deliver “unusual vessels” across oceans are a very special “profession”.
Harbour tugs and ferries are quite commonly delivered from building yard to wherever they will be operating, although HLVs has taken away a good part of this business.
Scrap ships are the other category that frequently use the service of specialized “Delivery Companies”.
It can be a risky business, since the vessels handled are not always suitable for long ocean crossings, or in good condition.
It takes a special breed of seamen to take on these tasks, as illustrated in this article: