The letter D.
Ape-ril and Bananuary
The D
D--Dos
Both their first names have six letters. That's it. For now. Edit: they're both dead.
T. Modern pirates are most likely based in Somalia, and T is the most common consonant in the Somali Latin alphabet.
The specific ocean.
Tequila! ... go to the home improvement store in December Fajitas!