From Yen Press:

On a whim, Aron Cornwall decides he wants to live a pirate's life of thrills, sailing on the high seas in search of distant lands and buried treasure. And when you are the son of a duke, you generally get what you want. Accompanied by his reluctant manservant, Robin, Aron scrounges up a crew—including a cook who cannot cook, a transvestite assassin, and a boy (girl?) genius—and sets off on the craziest pirate adventure you've ever seen!

Original Webtoon