Abstract: A new jacket design method is disclosed, especially for deepwater water heavy jacket applications. The method utilizes a special type of air bags, called Ship Launching Air Bags (SLAB), to provide low cost temporary buoyancy used for jacket installation purpose only. A designer only needs to satisfy the jacket stiffness for the resistance of environmental and gravity loads without the consideration of jacket reserve buoyancy. The required jacket reserve buoyancy could be increased with the utilization of temporally attached SLABs during the jacket installation.