And yet paragraph 4 advises to wash the face covering regularly, and not after every single use.
Sorry can’t see that section 4. Section 5 goes into detail about washing it every time you take it off.
When I follow the link it goes straight to section 9, paragraph 1 do not touch front of covering or part that has touched mouth or nose - check
Paragraph 2 once removed store in plastic bag until you have an opportunity to wash... - this could be taken to imply wash after every use
Para 3 make sure you clean surfaces the covering has touched and don't put on cafe table - well duh
Para 4 wash regularly and follow instructions for the fabric. - personally I think after every use goes beyond regularly, which implies one a day at most.
I see about not taking it on and off
in quick succession, that suggests to me if you are visiting multiple ships in a short space of time, just leave it on.
I suppose the last section of section 5 "when removing... wash in line...." could mean after single use, but then they could make a very clear statement once - "do not reapply a removed covering" which would cover all those other cases with more certainty