The method of water blasting is efficient and environmental friendly but the plates rust quickly but just as Tony said they are supposed to treat it immediately with a primer to deter this rust and then finish it with the special anti corrosive paint.
The grit blasting was causing a lot of damage to shore side machinery and in high winds being transported outside the yard damaging private properties, cars etc.
regards
Emmanuel.L.(Malta)

Thats a lot of flash rust there, i see a vid on youtube where there are water blasting saipem 10,000 with water and you can see the flash rust forming and they just paint over the flash rust with a grey primer, but the primers they use have anti corrosive additives and can be painted over fresh rust.

Yes MattyBoy , it is always money.money and money is the root of competition.
Alas to survive and compete you must be one step ahead of your competitors and that once again that cost money.
Competition is healthy but sometimes it is vicious and even cruel,laying down workers earning a living for their families to be replaced by robots and machinery.
regards and best wishes my friend.
Emmanuel.L.(Malta)

And of course, time is money. ;-)

You are not scraping a door or a house wall here,MattyBoy but metres of steel hull in a large drydock.
regards
Emmanuel.L.(Malta)

I wondered how they did that. I always thought they had a guy with a paint scraper !!