An airfoil comprising: pressure and suction side walls (86, 88) extending in a chord-wise direction between leading and trailing edges (82, 84), the pressure and suction side walls (86, 88) extending in a radial direction to provide an exterior airfoil surface; a core cooling passage (90a, 90b, 90c) arranged between the pressure and suction walls (86, 88) in a thickness direction and extending radially toward a tip; a skin passage arranged in one of the pressure and suction side walls (86, 88) to form a hot side wall at an outer surface and a cold side wall at an inner surface, wherein the skin passage extends a length in the radial direction, a width in a width direction, and a height in a thickness direction, the hot side wall defines a portion of the exterior airfoil surface, the cold side wall defines a portion of the core cooling passage (90a, 90b, 90c) at a core cooling passage surface, and the core cooling passage (90a, 90b, 90c) and the skin passage are configured to have a same direction of fluid flow; and a resupply hole which fluidly interconnects the core cooling and skin passages (90a, 90b, 90c, 98), wherein: a centerline of the resupply hole is arranged at an first angle relative to the direction of fluid flow in the core cooling passage (90a, 90b, 90c), the first angle lies in a plane parallel to the thickness direction, wherein the first angle is in a range of 5°-45°; and the centerline of the resupply hole is arranged at a second angle relative to the direction of fluid flow in the core cooling passage (90a, 90b, 90c), wherein the second angle lies in a plane parallel to the width direction, and the second angle is at an acute angle, the second angle being in a range of 15°-75°, characterised in that: the skin passage height is in a range of 0.25- 5.08 mm (0.010-0.200 inches), wherein the skin passage has an aspect ratio that varies between 3:1 ≥ H/W ≥ 1:5, and H corresponds to the skin passage height and W corresponds to a skin passage width. pressure and suction side walls (86, 88) extending in a chord-wise direction between leading and trailing edges (82, 84), the pressure and suction side walls (86, 88) extending in a radial direction to provide an exterior airfoil surface; a core cooling passage (90a, 90b, 90c) arranged between the pressure and suction walls (86, 88) in a thickness direction and extending radially toward a tip; a skin passage arranged in one of the pressure and suction side walls (86, 88) to form a hot side wall at an outer surface and a cold side wall at an inner surface, wherein the skin passage extends a length in the radial direction, a width in a width direction, and a height in a thickness direction, the hot side wall defines a portion of the exterior airfoil surface, the cold side wall defines a portion of the core cooling passage (90a, 90b, 90c) at a core cooling passage surface, and the core cooling passage (90a, 90b, 90c) and the skin passage are configured to have a same direction of fluid flow; and a resupply hole which fluidly interconnects the core cooling and skin passages (90a, 90b, 90c, 98), wherein: a centerline of the resupply hole is arranged at an first angle relative to the direction of fluid flow in the core cooling passage (90a, 90b, 90c), the first angle lies in a plane parallel to the thickness direction, wherein the first angle is in a range of 5°-45°; and the centerline of the resupply hole is arranged at a second angle relative to the direction of fluid flow in the core cooling passage (90a, 90b, 90c), wherein the second angle lies in a plane parallel to the width direction, and the second angle is at an acute angle, the second angle being in a range of 15°-75°, characterised in that: the skin passage height is in a range of 0.25- 5.08 mm (0.010-0.200 inches), wherein the skin passage has an aspect ratio that varies between 3:1 ≥ H/W ≥ 1:5, and H corresponds to the skin passage height and W corresponds to a skin passage width. a centerline of the resupply hole is arranged at an first angle relative to the direction of fluid flow in the core cooling passage (90a, 90b, 90c), the first angle lies in a plane parallel to the thickness direction, wherein the first angle is in a range of 5°-45°; and the centerline of the resupply hole is arranged at a second angle relative to the direction of fluid flow in the core cooling passage (90a, 90b, 90c), wherein the second angle lies in a plane parallel to the width direction, and the second angle is at an acute angle, the second angle being in a range of 15°-75°, characterised in that: the skin passage height is in a range of 0.25- 5.08 mm (0.010-0.200 inches), wherein the skin passage has an aspect ratio that varies between 3:1 ≥ H/W ≥ 1:5, and H corresponds to the skin passage height and W corresponds to a skin passage width.