The Sea Master was designed in the 80's for the G-38, Quadra 35. I have a Sea Master with a McCculough 35 with springstarter, much heavier than the G-38 and fly's awesome. I swing a 17X8 three blade with plenty of clearance. The plane hasn't flown in atleast 10 years due to lake access, but its a blast to fly. Mount the G-38 put a three bladed prop on it and trim the muffler stacks and you'll be just fine. Flying off water is that much fun. Good-Luck