I can see the stress in his eyes in the first picture. The poor dog. I can only think that his large size went against him. I’d say his feet got stuck in the mud in the canal and his heavy weight didn’t help at all. You would think with his strength he would have been able to pull himself out – however in the cold canal water his energy would have been sapped very quickly.
He’s a real beauty, he had a lucky escape. Has he got a name yet?