A vessel including a drilling installation for drilling a well, for example an oil, a gas, or a thermal well, by means of said installation, which installation comprises: - a substantially rectangular drill floor surrounding a vertically extending firing line; - a first drilling tower arranged on a deck of the vessel, said first drilling tower comprising a vertically extending frame with a length, a width and a thickness, the length of the frame being larger than the width of the frame and the width of the frame being larger than the thickness of the frame, wherein the frame comprises two elongated hollow casings arranged next to each other in the width direction of the frame, said casings extending substantially parallel to a longitudinal axis of the frame, said casings being rigidly connected to each other by one or more connection elements, and said casings being configured to transfer loads applied to the first drilling tower to the vessel, wherein the frame of the first drilling tower is positioned at a side of the drill floor, such that the longitudinal axis of the frame extends parallel to the firing line, and such that the longitudinal axis and the firing line are substantially aligned with each other in the width direction of the frame; - an additional tower support arranged between the deck of the vessel and an elevated position at the first drilling tower; - two storage devices for vertically storing drilling tubulars; - two pipe rackers (PR1, PR2), each pipe racker being associated with one of the two storage devices, and each pipe racker being configured to move drilling tubulars between the associated storage device and the firing line, wherein the two storage devices are positioned at opposite sides (S2, S3) of the drill floor, such that the storage devices and the drill floor are aligned with each other in the thickness direction of the frame of the first drilling tower, and wherein the casings of the frame of the first drilling tower each support one of the two pipe rackers. - a substantially rectangular drill floor surrounding a vertically extending firing line; - a first drilling tower arranged on a deck of the vessel, said first drilling tower comprising a vertically extending frame with a length, a width and a thickness, the length of the frame being larger than the width of the frame and the width of the frame being larger than the thickness of the frame, wherein the frame comprises two elongated hollow casings arranged next to each other in the width direction of the frame, said casings extending substantially parallel to a longitudinal axis of the frame, said casings being rigidly connected to each other by one or more connection elements, and said casings being configured to transfer loads applied to the first drilling tower to the vessel, wherein the frame of the first drilling tower is positioned at a side of the drill floor, such that the longitudinal axis of the frame extends parallel to the firing line, and such that the longitudinal axis and the firing line are substantially aligned with each other in the width direction of the frame; - an additional tower support arranged between the deck of the vessel and an elevated position at the first drilling tower; - two storage devices for vertically storing drilling tubulars; - two pipe rackers (PR1, PR2), each pipe racker being associated with one of the two storage devices, and each pipe racker being configured to move drilling tubulars between the associated storage device and the firing line,