The three owners were also avid swimmers, so they worked on the knit until it was good for swimming and not just splashing about in the water. In 1921 the team at Jantzen began marketing their suits as swimming suits instead of bathing suits. By then Jantzen suits were being marketed to both men and women, and their famous diving girl logo had been designed.
The Jantzen story is well-documented. The company advertised heavily and they also released catalogs for both retail and wholesale. I have a fair collection of them, mainly from the 1950s, so I was glad to get this earlier one.
Unlike some companies, Jantzen maintained an archive even after the original families sold the business. They have not only a nice collection of Jantzen swimsuits, but catalogs, artwork, and copies of the in-house magazine, Jantzen Yarns.
The Take-Off model came with a removable skirt that doubled as a cape. The straps could be adjusted for three different looks.
Jantzen developed several textured knits, like the Kava knit seen throughout this catalog. Lastex thread had been invented and marketed starting in 1931, but it took swimsuit makers a few years before they fully embraced the new (and improved) technology.