Systems are disclosed for curing composite parts within a container, wherein a pressurized environment may be created via a body of water. Disclosed systems may include the container, a heating system, and a mechanism for raising and/or lowering the container within the body of water. The container may include one or more rigid walls, one or more non-rigid walls, and/or one or more port holes extending through one or more of the rigid walls and/or non-rigid walls. Methods of curing composite parts using such systems are also disclosed. Methods may include providing a container having a cavity configured to receive a composite part, thermally coupling a heating system to the container, inserting the composite part into the cavity, submerging the container under a depth of external liquid, flowing a volume of fluid into the cavity, heating the volume of fluid, thereby curing the composite part.