[DETECTION] Why are the decks of these two vessels red?

[Why are the decks of these two vessels red?]
 

Automatically detected in the port of Severomorsk, classified as warships and identified as cruisers by Preligens' ship AI detector, these two Russian vessels are the Marechal Ustinov, a Slava-class missile cruiser (top) and the Pierre le Grand, a Kirov-class nuclear-powered cruiser (bottom).

The dynamic ruler tool in ©Robin can be used to confirm these identifications thanks to the respective lengths of 186.4 and 252 metres measured on the platform.
What these two cruisers have in common is the bright red colour that covers their outer decks.
This is the colour of the anti-rust and anti-corrosive 'red lead' paint applied to the iron and steel of the ships to reduce corrosion by limiting direct access of air and water to the metal. Often covered in grey paint for discretion and reduced visibility, some ships nevertheless retain all or part of their red surfaces.
 

Image: SecureWatch © 2023 Maxar Technologies / automatic detections Robin © 2023 Preligens