I knew an old timer that is no longer with us but had dug enough of them when they were legal to hunt to have an opinion on them ...he told me most of the time when a terrier was entered the otter would come to the dog makeing plenty of noise and would strike the dog but then would bolt more often than not ....he said that a steady sounder was preffered but had seen hard dogs that would kill foxes and work up close to brog they would work there otter with a bit of space in front ...but what he also said was it very much depended on the out lay of the otters holt if it was in a tight tube then