Gun dogs
I think you’re worrying unnecessarily here – many a labrador has had a similar operation following damage to its tail and I’ve yet to come across one that didn’t continue to work well in water.

This has certainly been the case with those labs brought to me for training with shortened tails – the docking hasn’t affected the way these dogs handled themselves in water.

Once the operation wound on your dog has healed completely there’s no reason why it should work any differently to how it did before the accident.

You only have to look at a spaniel that has had its tail docked at birth to see that water work is no problem at all.