Adam....

Pl.Qu 3441I is a Luftwaffe position.

Some links for Luftwaffe Map positioning info:

[www.stormbirds.com]
[www.gyges.dk]

The abbreviated (translated) U-30 KTB entry for 29-30 March 1940:

28.03.40 AN 2797 1600 FT ein: Notgelandetes Flugzeug suchen
29.03.40 AN 3425 0400 Notgewassertes Fl, dt "Do 18" gefunden.

(U-30) Kmdt: Da meiner Kenntnis nach kein Flugbergungsschiff
aus-gelaufen ist, nach Angabe der Flieger ein anderes Fahrzeug
das Flugzeug vor der See nicht abschleppen kann ohne daß dieses
kentert oder unter-schneidet, übernehme ich die 4 Mann der
Besatzung und versenke die "Do 18" mit Artillerie. Kurz nach mir
traf ein eigener Fischdampfer ein.

Approx. translation:
28.03.40 AN 2797 1600 FT: Search for a plane that made a forced landing
29.03.40 AN 3425 0400 emergency landing on water Fl, dt "Do 18".

(U-30) Kmdt: Because of my knowledge, no flight salvage ship
from-behind, according to the flyer another vehicle the aircraft from the sea
can not tow that without this capsize or under-cut, I take the 4 man Versenke
crew and the "Do 18" with artillery. Shortly after me met its own fish steamer.

[(U-30) Commander: No other salvage ships in the have been sent. Could
not tow the plane because of it's condition--capsized. 4 men taken aboard
and the aircraft was sunk with artillery. 4 men tranferred to a trawler
shortly thereafter]

Ref: Herbert Ritschel Vol. I - Page 176


Lat. and Long. for AN 3425
is approximately 58°03'00"N 04°59'18"E

This Kriegsmarine positioning location is found here:

[ubootwaffe.net]

Another converter can be found here:
[www.geocities.com]

Download the small zip file (Leif Andersson's MKQ Converter)
at the bottom of this page.
AN 3425 = 58°3.00 N 5°0.00 E


Regards,

Ken deshaies