Subscribe | UPI Odd Newsletter Subscribe July 26 (UPI) -- Charter boats lined a Virginia channel in the rain to protect dozens of wild ponies making their annual pilgrimage across the water. The 93rd annual Pony Swim from Assateague Island to Chincoteague Island took place on Wednesday as more than 50 ponies swam across the Assateague Channel under the guidance of the Saltwater Cowboys, a group of more than 50 riders. Advertisement The Chincoteague Volunteer Fire Co., which hosts the annual event, said the ponies swam the channel during slack tide, a 30-minute period when there's no current in the water. Dozens of tourists watched the swim from Veteran's Memorial Park, where rains left some spectators standing in knee-deep mud. "The mud will wash off, but the memories will last forever," Denise Bowden, Chincoteague Fire's spokeswoman, was quoted by the Virginian-Pilot newspaper as telling spectators. The ponies were given a veterinary checkup before the swim and paraded through town after resting from the trek. They are due to swim back to their home island on Friday. The annual swim, part of the local Pony Penning Week, was widely popularized by Marguerite Henry's 1947 book, Misty of Chincoteague. Advertisement Read More Animal rescuers lift pony stuck in bog Pony caught wandering streets of California city Florida police capture pony running loose on the highway Pony outruns oncoming train in narrow escape