What happened when J. once went on a water picnic with two ladies?

The narrator recalls this incident in Chapter VII of Three Men in a Boat. He launches into the story as he considers the clothing that is suitable for a boat trip. He and a male friend once went on a water picnic with two ladies who were impeccably dressed.

They were both beautifully got up – all lace and silky stuff, and flowers, and ribbons, and dainty shoes, and light gloves. But they were dressed for a photographic studio, not for a river picnic. They were the “boating costumes” of a French fashion-plate. It was ridiculous, fooling about in them anywhere near real earth, air, and water.

The women insisted that the boat was not clean, so the men dusted off the seats for them. And then there was the matter of getting wet. No matter which man was rowing and whether he was in the front or the back, he and his paddle inevitably brought drops or even splashes of water into the boat. The women tried to shield their dresses; but according to the narrator, the water marks never came out of the material. At lunchtime, when the boaters arrived at a park to eat and to relax, the women didn’t want to sit on the grass or against tree trunks. They spread their handkerchiefs on the lawn and sat very intently on them. Instead of enjoying the overall outing and the adventure, the women were only protective of their clothing. Obviously the narrator thought their behavior was silly.