Patagonia Women’s Shallow Seas Tank. A versatile summer tank named for the warm, calm, sunlit waters that host the greatest abundance of marine life on Earth. The Shallow Seas is made from a cool, calm blend of organic cotton and Tencel® lyocell (55%/45%) that wicks moisture away from the skin. The bra-friendly tank has a modest scoop neck and pairs brilliantly with our skirts and shorts. A slight opening at the back adds style and ventilation. Delicate side-notch openings at the hem accentuate the elegant drape. Hip length.