It's about girls' jet ski racing where water guns make your clothes fall off. That's a safety feature. The episodes have uncensored Blu-ray versions, with nipples. It's happy, shameless and surprisingly watchable.
It's also tamer than I'd expected. It's a booby anime, yes, but sleaze-hounds will be disappointed. There's no sex and no one does anything more salacious than having a bath. There's some lesbian subtext and the odd bit of innuendo, but that's all. Those nudifier water guns never go beyond underwear. It really is about jet skiing. There's the odd nipple, but baths are still haunted by mysterious glowing lights that mean you can hardly see anything.
It's good-natured. You'll laugh at it and won't feel dirty afterwards. The girls are almost all buxom, but not to a laughable degree and their clothes aren't absurd. (Well, unless you're a purist about fastening all shirt buttons.)
Our heroine is Rin Namiki, who's over-enthusiastic, adorable and a bit dim. She loves jet racing more than anything (thanks to her late mother), but she's also so friendly that she doesn't mind at all if you brutally crush her in a race. Classical sports anime heroine.
She also has emotionally expressive boobs. Seriously. When deeply moved or happy, she'll hold or dramatically move her bosom.
Her partner will be Misa Aoi, who's a humourless, strict worrywart with no social skills. Misa thought she'd given up racing, but she'd reckoned without Rin.
Their rivals include two lordly princess-a-likes from a filthy rich background, two Californian airheads with daft names and the ability to make rampant Engrish almost endearing, two lovable gyarus, two traditionally Japanese ladies with a hidden side and two woodenly cutesy idols who only stop being annoying when we see that underneath they're bitches.
Weakest episode: the OVA.
It's quite good. Not so good that you'd keep the episodes, but I'm happy to have watched the show. It's light-hearted and often funny, but also serious about its racing without (usually) overdoing it. Ep.4 was the only episode where I got tired of a race and wanted it to end. It helps that the races are relatively interesting, with everyone's machines having significant differences in weight, cornering, acceleration and so on. Different guns have advantages in different situations. The jet skis also have a boost button that adds unpredictability.
It's better than you'd think. It's amusing.