On Wednesday, 7 April 2021 at 23:37:35 UTC+1, John Rumm wrote:
..
Now check the pressure at the shrader valve. If it's less than
(typically) 3 bar, add air until it's at 3 bar.

For what it's worth I note that the instructions for my vessel say to pump it up to 0.2 bar less than the static pressure. I've always assumed it is to give a slight positive bias in the direction of intended travel so as to minimise stresses when it returns to the at-rest position.