This is Fiona creating knots Havanese style. But you say she is just running on the pool cover. Well, when it is wet, they rub and create knots.
So, we are ordering coats from Val for winter wetness to protect show coats. You can keep them warm and reduce the work and allow yours to play in the winter wet stuff slush. It won't save the feet but you can use a slicker on them. Just spray and slicker. I wouldn't suggest doing it everywhere unless you spray conditioner on crazy as it tends to break the hair and broken hair creates knots.
Then you will spend much time conditioning it to get it back in shape. I know - I have been doing it with Katsuro.
Have you bought your Havanese Grooming book? If not, we have one for sale from the HFC. It's not ours - its theirs but we have some of our dogs and tips in it and its worth its weight in gold.