<a href="https://en.wikipedia.org/wiki/Günther_Prien" id="mwgg" rel="mw:WikiLink" title="Günther Prien">Günther Prien</a> and the crew of <a href="https://en.wikipedia.org/wiki/German_submarine_U-47_(1938)" id="mwgw" rel="mw:WikiLink" title="German submarine U-47 (1938)">German submarine <i id="mwhA">U-47</i></a>, one of the most successful <a href="https://en.wikipedia.org/wiki/U-boat" id="mwhQ" rel="mw:WikiLink" title="U-boat">U-boats</a> of World War II, disappear without a trace.<sup about="#mwt41" class="mw-ref reference" data-mw='{"name":"ref","attrs":{},"body":{"id":"mw-reference-text-cite_note-6"}}' id="cite_ref-6" rel="dc:references" typeof="mw:Extension/ref"><a href="./March_7#cite_note-6" id="mwhg" style="counter-reset: mw-Ref 6;"><span class="mw-reflink-text" id="mwhw">[6]</span></a></sup>
<span class="mw-reference-text" id="mw-reference-text-cite_note-6"><cite about="#mwt38" class="citation web cs1" id="CITEREFHelgason">Helgason, Guðmundur. <a class="external text" href="http://uboat.net/boats/u47.htm" id="mwBhk" rel="mw:ExtLink nofollow">"The Type VIIB boat U-47"</a>. <i id="mwBho">German U-boats of WWII - uboat.net</i>. <a class="external text" href="https://web.archive.org/web/20001022012457/http://www.uboat.net/boats/u47.htm" id="mwBhs" rel="mw:ExtLink nofollow">Archived</a> from the original on 22 October 2000<span class="reference-accessdate" id="mwBhw">. Retrieved <span class="nowrap" id="mwBh0">28 February</span> 2010</span>.</cite><span about="#mwt38" class="Z3988" id="mwBh4" title="ctx_ver=Z39.88-2004&amp;rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&amp;rft.genre=unknown&amp;rft.jtitle=German+U-boats+of+WWII+-+uboat.net&amp;rft.atitle=The+Type+VIIB+boat+U-47&amp;rft.aulast=Helgason&amp;rft.aufirst=Gu%C3%B0mundur&amp;rft_id=http%3A%2F%2Fuboat.net%2Fboats%2Fu47.htm&amp;rfr_id=info%3Asid%2Fen.wikipedia.org%3AMarch+7"></span></span>