Jachthaven Wetterwille in Loosdrecht dates all the way back to the beginning of the twentieth century. In fact, the marina goes back to 1912! It was in the hands of the van Norden family for several decades until 1968, when one Gradus Kosters bought the family company.

The marina next door is known to the eldest villagers as "Het Plashuis", an outdoor swimming pool with club house that burned down in 1970. Afterwards, the owner, Mrs. Beekhuis, turned what remained into a marina and sold it to Mr. Kosters in 1982. The latter renamed it Interboat Holland.

The two marinas underwent some serious changes. The pontoons were refurbished and a marina office was built. At the beginning of the eighties, Gradus's son, called Gradus Jr. in great Dutch tradition, took over the company and continued its modernisation. On the Interboat site, he started selling motor sloops in a brand-new showroom. Named after the marina, Interboat sloops quickly grew into a reputed brand. Gradus Jr. stood at the helm of both marinas and the sloop company until his passing away in 1996.

The sloop division was sold, but Gradus's wife Mieke took it upon her to set forth the family business by managing the two marinas. She opened a bigger marina office and added a second restaurant and a gym to the premises while gradually renewing older pontoons. A newly built heated hangar and the existing showroom are now used for dry-stack storage, a system Jachthaven Wetterwille pioneered in the region.

Recently the marina welcomed ikSUP SHOP in the showroom, where fans of paddleboarding can buy equipment and even try paddleboarding with their dogs. Above the shop, a studio sleeps up to five people for weekend getaways and longer holidays. The roof of the showroom has been transformed into an eco-roof with room for several tents. Glamping with a million-euro view over the lakes!

Mieke's eldest daughter Catherine is involved in the company her grandfather started, as are her sisters. Until this day, Jachthaven Wetterwille prides itself on being a true family business, where everyone is made to feel at home.