The guy you see in the background here (Balto, a 70 lb White German Shepherd)

has been out twice on TRW. Both times he jumped overboard, and DOB drills were performed. He was hauled back aboard, and he was not a happy camper. However, another time he swam about 200 yards from the shore out to meet the boat as I was coming back in, when we were having a cookout at Lake Dias. So who knows? I don't think he likes being on the boat - all the motions tend to freak him out. Your mileage may vary according to dog type, size, etc. There are plenty of WCTSS folks who bring their dogs along, but they are generally in larger boats than the DS ...