From being a civilian employed as shipbuilder at the Royal Naval dockyards, he was commission in 1698 direct to the rank of commander (kommandørkaptajn)[1] despite not having followed the normal officer training pathway.

As chief of coastal defence from 1711 he was responsible for the scuttling of decommissioned warships to form the foundation of the sea fort Trekroner on the approaches to Copenhagen harbour.

[2] He is credited with 23 ships-of-the-line and nine frigates [3][4] Judichær introduced scientific method into the building of ships in Denmark, and was promoted over the period he was in post to eventually become Holmen’s Admiral in 1714.

In 1700 he refused to take defensive measures to block Flinterenden[Note 3] which the Swedish fleet nevertheless had problems navigating to join their British and Dutch allies in the bombardment of Copenhagen and troop landings at Humlebæk in August of that year.

In 1718 Judichær designed and built shallow draft floating mortar platforms for use in the rocky coastal waters of Sweden[1] In 1719 he used a diving bell designed and built by himself for investigation and raising of ships that had been sunk at Marstrand[1] With the end of the Great Northern War his detractors within the Danish Admiralty grew, led by the admirals Råben and Frants Trojel who complained about him to the king, Frederik IV, and accused him of bringing his office into disrepute.