Need take a note that a lot of ships scrapped at 70-s/80-s and some even at the end on 60-s which of cause never had an official IMO number are in ship's data bases under LR number as most data bases constructed on LR's data. http://www.shipspotting.com/gallery/photo.php?lid=2957413So, exempting the IMO/LR number to a separate log on the site will be shown as the Miramar number etc. it will loose ship details
for many ships with a number beginning by 9, while keeping data base for both logs will collapse the idea, and that looks unworkable.
Another point, that's impossible to define is it LR number or just the Miramar for numbers beginning by 9 unless compared with LR's data but that's unworkable for a simple site user.
Still the Miramar alternative could be used for CARGO ships beginning with numbers other than 9 including those with 3-4 digit numbers only.
Also, it could be a solution to have a link or a note on the site explaining IMO number and its use, for example: " IMO number is valid for ships existed after the year 1987, otherwise is the LR number" , also to rename IMO log to a LR/IMO log will be correct in fact.
Regarding to split IMO/LR numbers is more unrealistic idea as will need to process sub million photos to revise i.e. all ships deleted before the year 1987 at least