Luftwaffe pilot leads ASR launch to downed Whitley (1941)

Does anyone have any more information on on this incident from May 1941, reported in "YORKSHIRE AIRFIELDS IN THE SECOND WORLD WAR" p163 :

".....another crew from Leeming whose aircraft ditched following an attack on Schwerte owed their lives to the pilot of a Luftwaffe He111. Its pilot spotted the Whitley`s crew clinging to their upturned dinghy in bad weather and later found an RAF ASR launch which it successfully guided back to the dinghy. P/O Littlewood and his crew were landed at Yarmouth having changed their views somewhat on the Luftwaffe".

What an uplifting story, hopefully such things weren`t too rare in WWII and us (British/Commonwealth/American) hopefully did the same kind of thing..... But what I`m particularly interested in is how the Luftwaffe plane managed to communicate to the RAF launch what the problem was and then guide it to the dinghy.

 

Mnay Germans spoke English, so they might simply have blinkered in Morse, like the famous (probably apocryphal) story of an FW-200 Condor circling a convoy; supposedly one of the British ships signaled "Could you fly round in the other direction? You are making us dizzy" and the German complied.

Aircraft probably wouldn't have it, but there is an International Code of Signals used by naval and merchant ships, 1-3 letter groups with standardized meanings which can be sent by Morse, flaghoist, semaphore, or any other means. Each ship has a codebook in its own language, so they can send something like MAA - I need urgent medical advice - and have it understood by someone reading his own code book in his language.

 

How do you think the aircraft signalled to the launch ? Radio ? Signal lamp (difficult from a plane flying at 200mph ? ) ?