What was the name of Desmond Hume's sailboat?

Desmond Hume’s sailboat was named Elizabeth. The boat was given to Desmond by Elizabeth “Libby” Smith, whom he met while preparing for a sailing race around the world sponsored by Charles Widmore.

Libby explained that Elizabeth had belonged to her late husband, David, and that he had named it after her. Desmond used the yacht in his attempt to prove himself after leaving the British Army with a dishonourable discharge. A storm eventually wrecked his plans and left him stranded on the island.

The boat later becomes important in the island storyline. Kelvin Inman had repaired it and intended to use it to escape, prompting Desmond’s confrontation with him. After Desmond returns to the survivors’ camp, Jack, Sayid, Jin, and Sun also use the vessel in their efforts to reach the Others.

A common mix-up is Penelope, or “Penny,” Widmore: she is Desmond’s love interest, not the boat’s namesake. Elizabeth refers to Libby’s full first name and the yacht’s name.