Abstract: A device for righting a boat or other water vessel following a capsize. The device has an inflatable body which can be stowed in a collapsed state when uninflated. Compressed gas inflates the body following a capsize. The inflatable body has a flexible skin which forms at least first and second inflatable chambers. A valve arrangement causes the chambers to be inflated in a predetermined sequence. The first chamber securely mounts the valve upon the vessel. The second chamber is coupled to the first, supported by the first chamber when the device is deployed. Due to its buoyancy when submerged, the second chamber applies a righting moment to the vessel. The first chamber transmits this moment to the vessel. The staged inflation of the body alleviates its tendency to “pop up” to the surface before it is adequately inflated.