- later this week Dutch submarine replacement issues and requirements.
But the Walruses have operated mostly in shallow coastal waters (shallow immersion cycles). Hence the physical demands (contraction and expansion of the steel hulls causing metal fatigue) have been less than originally expected. Possibly the Walruses have been mainly used for signals monitoring as they are too slow for hunter-killer duties, chasing SSNs, SSGNs and SSBNs. The Walrus class operating life has therefore been increased to 35 years, allowing the subs to remain in use until at least 2025.
- modernising sensors, such as:
= new sonars allowing the sub to draw closer to the coast (aka “near shore”) to gather intelligence.
The suite includes a Mine and Obstacle Avoidance Sonar by ELAC Nautik.
= New optronics masts  from L-3 KEO permitting sub to quickly see 360 degrees around itself,
with less risk of discovery tan a periscope or older optronic. The new optronics suite includes a
thermal imaging camera  providing HD footage both day and night. Optronics allow very sharp
images to be visible on a screen for most in the sub's command center (not just one viewer's old
and them from current mod-4 standard to mod-7 CBASS.
= including a super high frequency (SHF) satellite communications system allowing messages to
the submarine from Dutch naval headquarters or NATO Defense Networks, and
= improved operating software for most systems (likely much work will be by Lockheed Martin).
 these sites are in Dutch. For a PC mouse - right click mouse - then you will see Translate to English - translation may take 20 seconds.