3. Wind. a. Wind velocity must not exceed 20 knots for sheltered water or 10 knots in semi-sheltered water. b. In a wind of 8 knots or less, the landing heading may vary up to 15 degrees from the wind direction. Where the surface winds exceed 8 knots the aircraft must land into the wind. No landing may be made in winds in excess of 20 knots. If a downwind landing or takeoff is absolutely required, this is made directly downwind. c. Surface swells must not exceed 1 foot in height and the windwave not more than 3 feet. The combination of swell and windwave must not exceed 3 feet in height when all swells and windwaves are in phase.