Not exactly the same, but my father-in-law always took his Dachshund's fishing on the saltflats of Texas. He'd let them swim around the boat while he was fishing. My wifey told me about one time while she was out with her father that their dog Mullet jumped in after some mullets that swam/jump by the boat (its where he got his name). Neither my wifey or he father thought much of it because he routinely did this so they didn't realize that once he was in the water he made a bee-line straight away from the boat. Before they realized it he was at the edge of a nearby large grassy patch. They called for him but he was too far away. They reeled in their line, pulled up anchor and set out to go after him but by the time they got there he was deep in the grass.
The grass grows from the saltflat beneath and it was too shallow for the boat but still to deep for a Doxie to walk in. They tried getting out of the boat to go after him, but they just sank in the silty bottom. In their panic, they called and called after him for about an hour and nothing. It was getting dark and they were trying to figure out what to tell my Mother-in-law before heading back when Mullet finally swam back out of the grass.
Doxies love to swim, but I don't think Mullet was having much fun out in that tall grass of the saltflats.