To create the strakes, in addition to creating the surfaces for the strakes, you are going to make a gap between the hull and strake surfaces. This gap will be filled with a blend surface to create a rounded "fillet" between the strakes and the hull surface.To create the gap you are going to offset the defining curves by .25" on each side and trim the hull surface to this line. Later you will perform the same trim on the strake surfaces. Then you can create a smooth blend surface between the strake surfaces and the hull surfaces to fill the gap.