The most common variant of this myth is that we were secretly refuelling German U-boats.Why would the Irish State at a time of fuel rationing have had the inclination to do such a thing?
Only feasible solution to that would have been for the Germans to pre cache fuel possibly enough just to limp back into Brest,and possibly a few torpedos in some extremely isolated bay or uninhabited island off the West coast.Big enough risk to do it even on such a scale,but some sort of secret U boat pen complete with personel and Swastika flags...Fantasy!
FWIW about the Swiss neutrality and supplying the Germans,TBH so did the Swedes.They supplied both Axis and Allied with precision ball bearings.The book "the Ball bearing run" is based on this.So yes the Swiss would have supplied the 3rd Reich,and the Allies,if they could have exported it to them.One thing however the Swiss were noted for was defending their airspace..There are several accounts of Luftwaffe and Swiss airforce skirmishes along the frontier.Must have been intresting as both sides were flying Messerschmit 109s.By 1945 the Swiss airforce had a large supply of both Axis and Allied aircraft that had landed in Switzerland and were pressed into service,unlike Ireland where we stripped them down and either transported them back to the border or junked them in the Curragh.Switzerland had also a high pouplation of USAAF,Luftwaffe,and RAF personel by the end.As really said where were you going to go as it is pretty difficult to get out of Switzerland if they dont want you to leave.
Looking at his actions,I really think he did walk the neutrality line in 39/45.His "blunder" of condolences at the German embassy has to be looked at in context of the times.Was he to know how long the war might have continued??Was it possible that the 3rd Reich could have fought on in the Alpen festung[if it existed under Doneitz?]It was a well known fact and confirmed,[but still kept mostly STHUM by Garda SB /G2 intell ] that Dev was a good personel friend of Hempel and did visit the German legation in a personal capacity on numerous occasions.
The slanted neutrality,well he finally realised after the disasterous economic war with Britan,that we needed them no matter what,to keep us supplied however meagerily with supplies to keep us going.
All in all for what he had ,and had to face on a world conflict,it was a good performance for an Irish politican