Here's a fresh info from Martin, unfortunately nothing what can make ham happy.
Update July 11.2016
" A really noisy platform.
Mounted the antennas onto the side of the helideck which is
above the equipment (radio) room after consulting with the onboard
On all three bands I see S8 to 9 noise with occassional peaks to 9+20.
Noise is from the main equipment room UPS systems and also from
the production level. Nothing I can do about it.
Tried four different locations and all except one has the same noise
levels. Just now have re-located the antennas to the very front of the
vessel just below the helideck. Still noisy but down an S point.
Pretty tired after a long day (up at 04:00) so will not do anything more
Work start time is 05:00Z so do not think I will get chance to get to
the radio until first break at 09:00Z and also at 11:30Z"
Thanks for Your effort Martin and GL tommorow.