Crime Kayak Murder Case: Experts Say It Was a Dangerous Day to Be on the Water Suspect Angelika Graswald's attorney says an autopsy performed found "no signs of foul play" By Diane Herbst Published on June 5, 2015 06:00 PM Share Tweet Pin Email Photo: Allyse Pulliam/Times Herald-Record/AP In the early evening of April 19, Vince Viafore and fiancée Angelika Graswald started paddling home from Bannerman Island in the Hudson River back to the mainland, against the current and into 16 mile-per-hour winds. Viafore – who was not wearing a life jacket – capsized, and prosecutors have charged Graswald with murder. They say she tampered with Viafore’s paddle and his kayak, removing a drain plug so the boat would fill with water. They also say she pulled a paddle from him and felt “happiness” when he drowned. Graswald’s motives, according to prosecutors, were dissatisfaction in the relationship – and two life insurance policies totaling $250,000. Graswald has plead not guilty. Viafore’s body was found May 23 and although the Orange County Medical Examiner’s Office and the Orange County District Attorney’s Office would not comment on the autopsy results, Graswald’s attorney Richard Portale tells PEOPLE examiners found “no signs of foul play.” The drain plug – which Portale says was removed by Viafore and not Graswald – may not be the smoking gun prosecutors are hoping for, according to kayaking experts, who also tell PEOPLE that several mistakes were made on that chilly mid-April day, increasing the danger of Viafore and Graswald’s outing on the Hudson. A Dangerous Day to Kayak The experts tell PEOPLE that the amount of water entering a small hole could be minimal compared to the amount of water splashing into the open cockpit of Viafore’s boat. He was using a Future Beach Fusion kayak, according to Portale. “More water will come into the cockpit area than the small little plug,” says Bill Garrison, owner of Hudson River kayak touring company Mountain Valley Guides, who saw a copy of the kayak’s owner’s manual. “It gets very tippy and you go over, and you can’t get back into the boat because it’s so unsteady due to the water inside of it.” Brian Grahn, owner of Hudson River Expeditions in Cold Spring, N.Y., who also saw a copy of the manual, says: “It’s not the best kayak to use on the Hudson River. The issue of flotation is a big one, a major one.” Garrison questioned the couple’s knowledge of kayaking. “Crossing the river stuck with me. Why were they doing that?” he says. “Crossing the river in 46-degree water without a life jacket – that’s kind of insane. That’s someone who doesn’t understand or respect the danger of that.” Viafore also lacked protective clothing such as a wetsuit or a drysuit. “I certainly would not be out on the Hudson River in 47-degree water without a dry suit on, that’s asking for trouble,” hypothermia expert Gordon Giesbrecht, PhD, professor of thermophysiology at the University of Manitoba in Winnipeg, Canada, tells PEOPLE. According to Giesbrecht, people immediately experience a cold-shock response when they hit 47-degree water – a gasp followed by hyperventilation of rapid, shallow breathing lasting from 30 seconds to 90 seconds. Then comes cold incapacitation, when muscles and nerves get colder and strength and coordination diminishes. “Your fingers and hands become weaker within minutes,” Giesbrecht says. “It would make it hard for him to hold onto the boat.” Adds Garrison: “People can’t just get in a kayak and go, you have to know what you are doing. It can get really choppy really quickly and the wind and the waves can be really dangerous.” Want to keep up with the latest crime coverage? Click here to get breaking crime news, ongoing trial coverage and details of intriguing unsolved cases in the True Crime Newsletter.