If you liked the Nadia: Secret Of Blue Water anime, the Anime-Planet community thinks you'd like:
For centuries, a group of strange children with white hair have been appearing again and again, their origins and purposes unknown; yet always, it would seem, they are searching for something or someone. Now, in the year 2012, they have come to the South Seas to search. There, they encounter the young martial artist Tohma, who has been helping two runaway children from a nearby orphanage, Helga and Chitto. As Tohma learns more about the mysterious children, he also discovers a startling truth about his new friend Helga. A story unfolds that goes back centuries and across the stars, and will change everything in Tohma's and Helga's lives.
In the distant future, spaceships (known as whales) are not demolished, they are abandoned amongst the stars and salvaged by "whale hunters". For young Lucky Luck, finding one of the most famous whale hunters named Ahab could be the hey to saving a planet from destruction, but at what cost? Now, Ahab, a mysterious android named Dew and the rest of the gang must set out to find and defeat the white whale, before a countless number of lives is lost...
One thousand years after the Giant Warriors caused an apocalyptic event known as the seven days of fire, humans are living in constant fear of the Toxic Jungle. This ever-spreading forest is filled with poisonous plants and gigantic monstrous insects; even the very air is deadly. Nausicaa is the kind and wise princess of a small, peaceful country known as the Valley of the Wind, which has so far avoided the spread of the forest. One night a large airship containing one of the Giant Warriors crashes into the valley. The following day soldiers from the powerful nation of Tolmekia invade the Valley of the Wind to reclaim and revive the warrior. As the only one who truly believes that there is a way for humans to live alongside the insects, Nausicaa must find a way to stop the war that now threatens her people and protect the Toxic Jungle before the Tolmekians burn it to the ground.
Edward Falcon is a would-be fighting champ with a father who left long ago to search for the mysterious and powerful Power Stones. After receiving what his father calls a precious stone, Edward finds himself constantly harassed by ninjas, samurai and others wanting to get their hands on it - even though he doesn't know what it is! Edward soon discovers that he's been entrusted with none other than a Power Stone, and from henceforth he tries his best to keep it safe, while also uncovering its secrets and trying to track down his father.
Nadia and Power Stone are both adventurous tales with comedic elements and slapstick villains. Both are fairly terrible in some ways, but Power Stone takes the case for awfulness. Regardless, as they're aimed at the same age level and have a very similar feel, fans of one might enjoy the other.
Having lost her mother at birth, Jane Buxton grows up with her brother George the dreamer and her moody step-brother William. George sets off to seek a legendary 'floating liquid' that he hopes can revolutionize transportation and bring about human flight, but word soon returns of his tragic death. Convinced that her brother is still alive, Jane courageously sets off to find him, and encounters a world of adventure.
Nadia and Secret of Cerulean Sand, are both family friendly adventures set in the past.
They also both have a set of young main protagonists, that are part of a larger team set up on a mission.
The similar themes do not stop there. The two shows have amazing machines that stretch the possibility of inventions far beyond thier years, but use materials that would have been readily available. Wood/Rivets/steam engines.