temperatures produce a twin challenge: in the first half of her swim the warm water will dehydrate her body, while in the second half her body temperature will drop and she will face potential hypothermia. Nyad had bulked up her physique to about 150 pounds/70 kg (15 pounds/7 kg more than she weighed in 2010) to help counter the loss of body mass during her grueling swim. Nyad was escorted by a paddler in a kayak equipped with an electronic shark repellent known as a Shark Shield. To keep Nyad swimming in a straight line, her specially designed, slow-moving catamaran support boat deployed a streamer: a long pole keeps the streamer several yards away from the boat, and the streamer is designed to remain about 5 feet underwater, so that Nyad can swim above it, much like following a lane line in a swimming pool. At night, the white streamer was replaced by a string of red LED lights. Writing in her blog in July 2011, Nyad stated that the development of the submerged guide streamer, in early summer 2011, may be the single greatest aid to her marathon swim. In all of her previous swims, she had trouble keeping the support boat in sight and was prone to veer off-course. Keeping a boat headed in a straight line, in the ocean, while moving at only 1 to 2 knots is very difficult, and her catamaran is equipped with thrusters and a special sea anchor (in case of following seas) to stabilize its course. Second attempt Some 33 years after her first attempt in 1978, Nyad entered the water again at Havana on August 7, 2011 at 7:45PM, a CNN news team on board her support ship to provide live coverage of her swim, which involved electronic "Shark Shields" but no shark cage. Nyad stopped her attempt early in the morning on August 9 at 12:45AM after 29 hours in the water, after encountering strong currents and winds that pushed her miles off course to the east. Nyad also said she had been suffering shoulder pain since her third hour in the water, but what made her abandon the effort was a flare-up of her asthma, such that, throughout the final hour, she could only swim a few strokes before repeatedly having to roll on her back to catch her breath. Third attempt On September 23, 2011, Diana Nyad began