19-32. All aircraft involved in operations near or over water will normally carry a water survival kit that contains sea dye markers. If you are in a water survival situation, use sea dye markers during daylight to indicate your location. These spots of dye stay conspicuous for about 3 hours, except in very rough seas. Use them only if you are in a friendly area. Keep the markers wrapped until you are ready to use them. The sea dye is visible at a distance of more than 11 kilometers (7 miles) from an aircraft at 2,000 feet, so you should use them only when you hear or sight an aircraft. To further conserve them do not use them all at once. Dip the marker bag in the water until a slick about 30 meters (100 feet) appears. Sea dye markers are also very effective on snow-covered ground; use them to write distress code letters.