I've seen that people on TouchArcade and Steam Guides improved that saving the submariner is impossible.But then the "save a sailor from amputation" on IGN guide has to do with a ship route.Here are all the ship routes I found:
1.Amsterdam-Kristiania/2.Amsterdam-Munich/3.Nice-Rome-Tunis/4.Venice-Athens/5.Copenhagen-Stockholm-Helsinki/6.Stockholm-Helsinki-St Petersburg/7.Stockholm-Warsaw/8.Warsaw-Stockholm-Helsinki/9.Thessaloniki-Izmir/10.Athens-Izmir/11.Athens-Alexandria-Cairo(maybe divert to Antalya)/12.Antalya-Beirut-Alexandria-Cairo/13.Alexandria-Suez/14.Odessa-Istanbul and backwards/15.Istanbul-Novorossiysk/16.Aswan-Wadi Halfa/17.Ujiji-Nsenga/18.Astrakhan-Baku-Tehran/19.Tehran-Baku/20.Baku-Krasnovodsk/21.Stone Town-Aden and backwards/22.Suez-Jeddah-Aden-Bombay/23.Aden-Muscat/24.Dubai-Bandar Abbas and backwards/25.Manama-Dubai-Muscat/26.Muscat-Karachi/27.Manama-Bombay/28.Nova Goa-Colombo/29.Madras-Waltair(and backwards)-Calcutta/30.Antananarivo-Colombo-Madras.More coming soon.If you do like travelling,help me find that route!