Sandbars are very shallow areas in the sea where ships can get stuck in the sand. Syrtis is located on the coast of Libya, northern Africa. (See: [[rc://en/ta/man/translate/translate-names]])
A sea anchor is something that is towed in the water behind a ship to slow the ship down and make it more stable. It may be a large cloth or a stiff board. Alternate translation: "they let the floating anchor down into the water"
This can be stated in active form. Alternate translation: "had to go in whatever direction the wind blew us" (See: [[rc://en/ta/man/translate/figs-activepassive]])