Original caption with above photograph:

Das große Flugboot Rohrbach „Romar“ D-1734 stürzte am 10. September 1929 in der Nähe von Grömitz in die Ostsee. Es befand sich auf einem Probeflug in niedriger Höhe über dem Meer (zwecks Untersuchung des sog. Luftkissen-Effekts), als unvermittelt das rechte der drei Triebwerke aussetzte. Die beim Aufschlag auf das Wasser entstandenen Lecks waren so erheblich, daß die Maschine nach relativ kurzer Zeit sank. Das Wrack wurde zwar wieder gehoben, aber dann verschrottet. Die offizielle Ausbuchung der D-1734 in den amtlichen NfL (Nachrichten für Luftfahrer) erfolgte erst mit 2 ½ jähriger Verspätung. (Slg. Frost/ADL)

Translation:

On September 10, 1929, the giant flying boat Rohrbach „Romar“ D-1734 crashed in the Ost Sea, in the neighborhood of Grömitz. It was on a test-flight at low altitude investigating the so-called aerodynamic ‘ground effect’  (i.e. the influence of the closeness of the  ground on lift and speed), when suddenly the rightmost engine stalled. The impact on the water surface created so much leakage that the aircraft sank after a relatively short time.  Although the wreckage was salvaged, it was declared total loss. The actual deletion from the official register NfL (Nachrichten für Luftfahrer) did not take place until 2^1/2 years later. (transl.rs)

The magazine AERONAUTICS reports on  Sep. 23, 1929 under ‘Flights & Flyers’:
“Furious was Dr. Adolf K. Rohrbach, head of the Rohrbach Metall-Flugzeugbau, who was in Manhattan last week.
One of the three huge tri-motored Rohrbach-Romar seaplanes his company has built for Luft Hansa’s trans-Atlantic service crashed at Travemünde, Germany, floated for 90 minutes, then sank.
Thirteen passengers and crew were saved. The crash was due to test flying at low speed. The sinking was because hull portholes and bulkhead doors had not been closed as Dr. Rohrbach had ordered.”

In fact, this fatal crash would herald the end of the Rohrbach story.

See the
DR. ADOLF ROHRBACH CHRONICLES
on the top of this page.

(source of the featured image:    www.adl-luftfahrthistorik.de