GB-Edinburgh: Wartsila 4L20 Main Engine (SPEMOS) Upgrade

Description

1.2.NLV Pharos currently uses a SPEMOS (SpEed MOnitoring System), which is a proprietary relay system developed for Wartsila (Finland) engines to monitor engine speed, and perform several configurable relay functions. In August 2023, Wartsila issued Technical Bulletin WS23T546, "Lifecycle status announcement, DESPEMES and SPEMOS speed monitoring system" (Annex A), which advised that the SPEMOS system is entering obsolescence. See also Annex B: Technical Bulletin 2011T268, " Temperature monitoring system for balancing shaft bearings on W4L20 and WA4L20". Annex C: Technical Bulletin WS23T644, "Lifecycle status announcement, Woodward 723 and 723 Plus speed control products". NLB requires to protect its vessels from obsolescence, and therefore an upgrade is required to ensure future operability of the SPEMOS system. Wartsila have advised that WSSS (Start/Stop Safety System) addresses the current SPEMOS obsolescence, plus safeguards against future obsolescence & includes the balancing shaft monitoring system for the 4L20's. This upgrade also addresses the Woodward 723 obsolescence highlighted in bulletin WS23T644.