ECDIS standard symbol SY(WRECKS05) - dangerous wreck, depth unknown
International Hydrographic Organization (IHO)
<a rel="nofollow" class="external text" href="http://www.iho.shom.fr/publicat/free/files/PresLib_e3.4_Part_I_Addendum.pdf">IHO Publication S-52 Appendix 2: Addendum to annex A, part I, users´ manual. Edition 3.4 (2008): Paper based description of symbols for use on ECDIS</a>