The Sailing of the Yellow Cog
By NC Wyeth. [Golden Age Comic Book Stories]
By Katie Cook. [There are several more in that link.]
The Santa Clause
By Mattias Adolfsson. [Lots more in that link too, including Robo Santa, Western Santa, Jazz Santa, and - gasp! - Nude Santa.]
By Basil Wolverton. [Golden Age Comic Book Stories]
By Anthony Carpenter.
Ms. Sassy Lady Viking Shark
By Megan Dong.
Mermaid Sailboat Mishap
By Ham Hopfmuller. [Never Sea Land]
By Alex Mitchell. [Part of a Seven Samurai version of the JLA at Project: Rooftop.]
Aquaman and Wonder Woman
By Eric Canate. [JimSmash!!!]
Stranded on Monster Island
By Edvard Moritz. [Admiral Cal]