Royal Norwegian Navy (RNN)
The Royal Norwegian Navy projected a replacement requirment for more than 20 high-speed patrol/attack craft in the mid 1990s. Their experience with several charter evaluations of the Cirrus 120 passenger (SES) has established a favorable climate for SES. Since 1989, Cirrus has been developing designs for 33 meter and 42 meter fast-patrol craft. The 42 meter craft CIRR-42 was selected as the most suitable candidate for the Royal Norwegian Navy program. To finance and market the CIRR 42, Cirrus combined with DNV and IMX, whose specialty is defense marketing, to establish what they have called Nortest Group. A consortium of equipment and weapons companies also proposed to support the prototype.
The CIRR 42 is of cored GRP construction (Composite) with turbine/diesel waterjet propulsion providing a service speed between 50-60 knots. Full-load displacement is just over 200 tons.
![[ img ]](https://i.imgur.com/h427INj.png)
Things that changed from CIRR 42 to Skjold class:
- They made here wider, the Prototype HNoMS Skjold was splitt in half and widen. to improve the ship lift area for the SES hull at speed, some also improved the sea-capability.
- The Turbine/diesel propulsion was replaced with turbine/turbine propulsion. Due to the combination of high rom turbine and low rpm diesel engine, kept destroying the gearbox. It was found that the gearbox could handle the massive friction between an engine at low rpm and high rpm was combining the output.
