Marine Lumber is not a structural material. The framing or structure it is attached to must be able to withstand any stress or load it may be subject to. Marine Lumber is an excellent product to make non load bearing products with such as, electronic boxes, cabinet doors, fish or bait boxes, instrumentation panel, cutting boards, seat backs and shower floor or walkway floor that does not need to be sealed. Do not use where Marine Lumber will be subject to temperatures above 180 degrees F.
Marine Lumber differs from wood because it reacts more to temperature change. Marine Lumber contracts and expands at the rate of 6x10-5 in/in/F° which translates to 1/32" for every linear foot of length or width over a 40° temperature range. Cut and Drill your material accordingly.