A tubular installation system for J-laying tubulars wherein the system comprises: - a J-lay tower structure for lowering and/or raising tubulars and accessories along a firing line extending along the J-lay tower structure; - a support for supporting the J-lay tower structure; - a tubulars supply system, preferably provided on the support, for supplying tubulars to an essentially horizontal tubular supply position in the vicinity of the J-lay tower structure, - a loader device for transporting a tubular between an essentially horizontal supply position and the firing line, wherein the loader device comprises: ∘ a tubular gripper (21a, 21b, 21c) adapted for gripping the tubular, ∘ a base, preferably provided on the support, ∘ a boom to which the one or more tubular grippers are attached, which boom is pivotable with respect to the base in a boom pivot direction about a horizontal boom pivot axis, between a lowered position for gripping a tubular in the essentially horizontal tubular supply position, and a raised position for delivering a tubular to the firing line and vice versa, - an accessory supply system, preferably provided on the support, for supplying an accessory to an essentially horizontal accessory supply position in the vicinity of the J-lay tower structure, - accessory handling means for transporting the accessory between the essentially horizontal accessory supply position and the firing line, characterized in that the accessory handling means comprise accessory rails (59a, 59b, 59c, 59d), and the accessory supply system comprises accessory supply rails (58a, 58b; 201, 202), provided on the support, which accessory supply rails extend towards the essentially horizontal accessory supply position, and which accessory supply rails are provided in line with the accessory rails of the accessory handling means to supply an accessory directly from the supply rails to the accessory handling means in the essentially horizontal accessory supply position. - a J-lay tower structure for lowering and/or raising tubulars and accessories along a firing line extending along the J-lay tower structure; - a support for supporting the J-lay tower structure; - a tubulars supply system, preferably provided on the support, for supplying tubulars to an essentially horizontal tubular supply position in the vicinity of the J-lay tower structure, - a loader device for transporting a tubular between an essentially horizontal supply position and the firing line, wherein the loader device comprises: ∘ a tubular gripper (21a, 21b, 21c) adapted for gripping the tubular, ∘ a base, preferably provided on the support, ∘ a boom to which the one or more tubular grippers are attached, which boom is pivotable with respect to the base in a boom pivot direction about a horizontal boom pivot axis, between a lowered position for gripping a tubular in the essentially horizontal tubular supply position, and a raised position for delivering a tubular to the firing line and vice versa, ∘ a tubular gripper (21a, 21b, 21c) adapted for gripping the tubular, ∘ a base, preferably provided on the support, ∘ a boom to which the one or more tubular grippers are attached, which boom is pivotable with respect to the base in a boom pivot direction about a horizontal boom pivot axis, between a lowered position for gripping a tubular in the essentially horizontal tubular supply position, and a raised position for delivering a tubular to the firing line and vice versa, - an accessory supply system, preferably provided on the support, for supplying an accessory to an essentially horizontal accessory supply position in the vicinity of the J-lay tower structure, - accessory handling means for transporting the accessory between the essentially horizontal accessory supply position and the firing line,