A spar hull for a floating vessel can include a hard tank having a belly portion, a fixed strake coupled to the outer surface of the tank and a folding strake coupled to the belly portion of the tank, the folding strake having one or more strake panels and one or more support frames. A method for installing folding belly strakes on a spar hull may include providing a floating spar hull having a hard tank with a belly side, rotating the spar so that the belly side is in a first workable position, coupling at least one folding strake to the belly side of the spar, and coupling the strake in a folded position for transport. The method may include positioning the spar hull offshore in a transport position, upending the spar hull, unfolding the strake, fixing the strake in the unfolded position and installing the spar hull.