Abstract: A method for protection of underwater structures and earthen surfaces. A biodegradable bag is filled with particulate material, such as a cement mixture, and placed underwater so as to protect an underwater structure from damage. The bag has a multi-layer wall, with an outer layer of a biodegradable fabric such as burlap, and an inner layer of a biodegradable material which is permeable to water yet which will not permit very fine solids to pass through the material. A suitable inner layer material is heavy kraft paper. After placement underwater, water penetrates the wall layers and hydrates the cement, eventually forming a firm mass. Another embodiment of the bag comprises a filler tube formed from the bag wall material, which extends into the interior of the bag sufficiently far that escape of the particulate material is minimized during the filling of the bag.

Abstract: A method of manufacturing an inflatable dunnage bag having a wall construction of two integrally fused layers of thermoplastic polymer, the outer layer of which is a sleeve of strips of woven polymer, the inner of layer of which is a continuous layer of gas impervious polymer. The ends of the sleeve are sealed against the escape of gas. The wall of the bag has a valve for the admittance of gas to the interior of the bag. The bag is formed by deposition of a continuous molten layer of gas impervious polymer to a sleeve of strips of woven polymer, installing a valve for admittance of gas into the wall of the sleeve and forming a gas tight seal at the ends of the sleeve. Deposition of the continuous layer of gas impervious polymer may be a two-step process wherein a molten layer of gas impervious polymer is deposited to one exterior side of the flattened sleeve, then to the other exterior side of the flattened sleeve and the sleeve turned “inside-out”.

Abstract: An inflatable dunnage bag having a wall construction of two integrally fused layers of thermoplastic polymer, the outer layer of which is a sleeve of strips of woven polymer, the inner of layer of which is a continuous layer of gas impervious polymer. The ends of the sleeve are sealed against the escape of gas. The wall of the bag has a means for the admittance of gas to the interior of the bag. The bag is formed by deposition of a continuous molten layer of gas impervious polymer to a sleeve of strips of woven polymer, installing a means for admittance of gas into the wall of the sleeve and forming a gas tight seal at the ends of the sleeve. Deposition of the continuous layer of gas impervious polymer may be a two-step process wherein a molten layer of gas impervious polymer is deposited to one exterior side of the flattened sleeve, then to the other exterior side of the flattened sleeve and the sleeve turned “inside-out”.