ok but that's 12" armour. But doesn't necessarily mean we went to the other extreme, i.e. that a modern military ship has the same hull than a trawler. A quick

ok but that's 12" armour. But doesn't necessarily mean we went to the other extreme, i.e. that a modern military ship has the same hull than a trawler. A quick google search suggests the thickness of an ice breaker hull seems to be about 2 inches.