CMP round roof hatch padding?

[Grant Bowker]

The original appears to be laminated from three layers of coarse brown felt. The present thickness totals 1-1/4" but I suspect that when new it may have been 1-1/2" thick .
The first thing I plan to try as replacement is three layers of cheap blue nominal 1/2" camping mat (actual thickness for three layers glued together is 1-3/8"). In addition to being cheap it has some give but isn't soft like foam and is not water absorbent. It doesn't show, so may be an acceptable substitute.