Completely agree, I can just about swim a length of the pool at most, I'm not at all a confident swimmer as I only learnt the limited skills I have about 3 years ago.
Would I get in a pool? Absolutely (tbh I did even before I could swim, just made sure to keep to the shallow end, I venture into the deeper end now!)
Would I go in open water? Under no circumstances.
I don't get her at all, she was shaking like a shitting dog when they went out on that boat (although maybe that was because Slosh was over the limit!) because she can't swim, you never see her in the pool because she can't swim, yet now she's in the sea?!
As a pp said, she'll do anything to get out of parenting poor W (on which note I couldn't help but smile about how clearly he said 'cat' yesterday. His speech is coming on leaps and bounds, albeit zero thanks to his parents)