Google is misinformed, I'm afraid. From the RNLI site itself:
"Whilst our operational volunteers give their time freely to help save lives, the RNLI does make payments to recognise the cost and disruption that this can cause.
To ensure they are not out of pocket, these volunteers can claim necessary expenses and, in specific cases, a contribution for lost wages, such as when attending a residential training course.
The RNLI also, in certain circumstances, may make a fixed payment where there is a shortage of specific skills, such as maintaining and operating our increasingly technical lifeboats."
There's a great deal more about this and all members of the lifeboat crew are either fully salaried which may surprise many, or are provided as shown above.
I agree that their work is very worthy indeed, but examining the annual accounts for the RNLI can provide interesting reading.