A new technology should be added in the Hideout research. Each level will make a trade fleet invincible, these invincible trade fleet's danger will not get affected by the Voodoo's (HN's, FFJ's etc. usual port danger is still applicable ). Research should be done for maximum of 20 levels, so only 20 fleets can be protected this way.
After each level of research is completed, system should let the user to pick a fleet to make it Invincible. The invincible fleet can have only the following ships (listed below), if the user selected a fleet which has any other ships not listed below, then a error message should be thrown saying 'Ship type requirement did not match '
Howker,
Cutter,
Sloop,
Fluyt,
Galleon,
Large Fluyt,
Merchantman,
Trade Galleon,
Large Merchantman