Frederik Kaas (1730 – 10 September 1759)[1] was a Danish naval officer who also saw service with other navies.

From the age of twelve Frederik Kaas was enrolled as a cadet in the Royal Danish navy (officially from 1747) and was commissioned as a Junior Lieutenant on 27 December 1749.

In 1750 he joined the Construction Committee[1][Note 1] 1751 -1754 he served on the ship-of-the-line Nellebladet in a voyage to the East Indies, at the end of which he was promoted to Senior Lieutenant and appointed adjutant to the head of the Holmen navy base, Admiral Suhm.

[1] Early in 1776 promotion to captain gave him command of Hvide Ørn (1753) which was active in a joint Danish-Swedish squadron in the North Sea In 1757 Frederik Kaas was permitted to seek service in the French navy.

[Note 2] He reported that he had arrived too late at Brest to join the squadron of Bois de la Motte, but in August he was posted to a warship of 74 guns which was sailing to the East Indies.