I am out of my depth here but I am going to try and write a little about this. Thoroughbred models in the US produce a range of white metal ships. Peter Pig in the UK have a nice range Hammerin' Iron that also includes 3mm troop blocks and coastal features. There are some 1/600 SCALE IRONCLADS 1870 TO PRE-DREADNOUGHT from Old Glory.
Rules seem to be in abundance - anyone out there have any knowledge about this scale?