Britannic's 2nd funnel

[AquataniaFan]

Why were Britannic's funnels painted yellow? Britannic was launched before WW1 so I'm confused as to why they took the black off in favor of yellow, it doesn't really make anything different so can someone clarify this for me.

 

[Ioannis Georgiou]

Why were Britannic's funnels painted yellow? Britannic was launched before WW1 so I'm confused as to why they took the black off in favor of yellow,

She was to be used as a Hospital Ship and Hospital Ships had yellow funnels.
When launched she was an empty hull. During fitting out the funnels were unpainted as far as I know.