Le Diadème

Posted by F.F. on Saturday 22nd of November 2025 16:22

@ Kathleen Landel

I think (I'm not sure) there's a mistake regarding the name of the ship.

As Claude du Campe de Rosamel was in 1840 a retired naval minister, I guess the Rosamel refered to in your comment was rather Joseph, who in 1840 was in command of a frigate designed with a battery of 24 pounders, la Danaé. Maybe her name, which sounds a bit like le Diadème, caused confusion?

Le Diadème was a second rate ship of the line, in size and in firepower not inferior to what were the British first rates before the Hibernia of 1804. Such ships had a complement of some 850 men, a broadside of some 500 ㎏ ≈ 1,100 ℔, a displacement of over 3700ｔ (SI), a burthen of 2043 « tonneaux de jauge » (French measurements) or 2,258 tons (English measurements). Because of their draught of water they were unkikely to be used in places like Hawaiian shores. Frigates with 24 pounders had a crew of some 450; their broadside was hardly one half of that of a 80-gun ship of the line (but comparisons were a bit difficult after the French Navy, in 1838, adopted the 30 pounder as its only caliber). La Danaé had a displacement of 2300ｔ (SI), and a burthen, as measured in England, of some 1,500 tons.

« Pohnpei. Micronésie en 1840 », is the title of a book reporting the journey in the Pacific of la Danaé in 1840.

Posted by Kathleen Landel on Monday 17th of November 2025 08:54

I have a primary source document from the Hawaii Archives placing this ship in the Honolulu port on July 21, 1840 commanded by Du Campe de Rosamel. This was several years after the Laplace incident (Rosamel served with Laplace) and the document notes the ongoing tensions with the French. The document is a confidential message to Kamehameha III about the ship’s presence at the port. Is there any record of this Pacific voyage?