Nudity Required

[Torchwatch]

In the UK there used to be a Personal Survival Swimming Award in which kids had to swim 25m and tread water for 5 minutes in pyjamas. The idea was to simulate falling into a river fully dressed, swimming to a safe place then staying afloat until rescued.
At the end of 5 mins they were required to undress in the water, tie closed the ankles of their pyjama bottoms, swing them around their heads trapping air, then use them as a float.
Swimming in pyjamas is hard work, the kids were always relieved when they were allowed to strip them off.
Swimming in big baggy shorts is almost the same as swimming in pyjama bottoms. In big seas with rip tides they can get weak swimmers drowned.
Short shorts are more practicle but without a waist cord the water will drag them down around your ankles.
If you want to swim faster you'll turn to square cuts and/or speedos, the skin tight elasticated fabrics cut resistance with the water and allow you flow through the water better.
Some swimmers will move to wearing swim bikinis on the beach, the less fabric the lower the water resistance will be. You may be tempted to try a swim thong and feel your body flowing sensuously through the water like a seal.
By this time you will have become used to wearing almost nothing on fairly quiet beaches and may become curious about swimming naked. Even in wet board shorts people can see your bulge about the same as if wearing a wet bikini, you may as well get naked.