A person that you appreciate immensely. It is also the title you receive after you've done something awesome. Depending on the awesomeness of the action you might even be a delicious canoe or a delicious cruise ship or a hooker boat.
The opposite of a delicious boat is a malicious boat.
"I've made some cookies for you!"
"Aw, thank you! You're such a delicious boat."
A wonderful person, someone who you appreciate having around. Mostly used as a term of affection for someone who's just done you a favor.
"Did you get me coffee? Thank you! You are a delicious boat."
"The worst thing I can say about that girl is that she is not a delicious boat."