https://navserver2.navtor.com/Portal.svc "Navtor server"
https://navstorage.navtor.com/portaldata/EncCatalog-version "Navtor blob server"
http://ak.dynamic.t0.tiles.virtualearth.net/comp/ch/0?mkt=en-us&it=G,VE,BX,L,LA "Bing maps server"
http://services.arcgisonline.com/ArcGIS/rest/services/Ocean_Basemap/MapServer/tile/0/0/0 "ESRI server"