Abstract: The double deadrise with multiple reflex chine boat hull structure and engine mounting system relate to designs for power boat hull structures and engine mounting systems. The hull structure combines the use of two pairs of bottom surfaces, reflex chines and side panels to form a double deadrise hull structure. This design imparts a highly efficient means for dynamic tracking, thereby, preventing "slide-out". The design also enables the hull structure to quickly and easily achieve a plane. The engine mounting device provides an improved means for securing and supporting an engine to a hull structure. The engine mounting device permits the hull structure to have a high transom, reduces the space in the working compartment that would otherwise be occupied by the engine, engine housing, or engine well, permits the proper positioning of the propeller within the water reservoir to achieve optimum thrust performance, provides static flotation and incorporates all of the benefits achieved in the new hull design.