Following earlier trials, the USS DELAWARE (SSN 791), a VIRGINIA-class SNN, successfully completed the very first operational task with the YELLOW MORAY system, namely the launch and recovery of REMUS 600 Uncrewed Underwater Vehicle from the torpedo tube. This event, carried out in European waters during exercises in EUCOM’s area of responsibility, marks the first-ever forward deployed submarine torpedo tube launch and recovery of a UUV to complete a tactical objective.

The YELLOW MORAY system is being collaboratively developed within AUKUS Pillar II and is a capability that the Royal Navy will also be acquiring (in the UK it is known as Project SCYLLA).

According to the US Navy, DELAWARE executed 3 YELLOW MORAY UUV sorties of about 6-10 hours each, employing the same vehicle, validating the reliability of the system and the ability to execute multiple missions without the need for divers to launch and recover the vehicle.

It was not all smooth sailing: according to the US Navy, earlier attempts were made in February this year “in a Norwegian Fjord”, but in that occasion the REMUS 600 vehicle failed to recover to the torpedo tube after multiple attempts. The UUV had to be recovered to a surface support vessels, where “damage to a critical part” was identified. The vehicle was shipped back to the US and had the failed component replaced before being returned to DELAWARE during an “expeditionary reload” ahead of further exercise opportunities. Finally, multiple successful launches and recoveries were scored. The “expeditionary reload” in Norway also marked the first-ever pierside diver torpedo tube load of the UUV in Norway.

The missions of the UUV deployed from torpedo tubes include, but are not limited to, seabed mapping, mine detection, and intelligence gathering. It must be noted that an alternative system also underwent successful trials in controlled circumstances already during 2023: the RAT CATCHER by Leidos/L3Harris launches and recovers the IVER4 UUV.

The Royal Navy, just like the US Navy, employs both types of UUVs. It is not clear exactly how common the british SCYLLA system is to the American ones. A recent official presentation by Royal Navy officer David Burton, Director NATO ASW Barrier Programme (a UK-led NATO Smart Defence initiative) noted that, after initial delays, SCYLLA trials were delivered in Q3 2024.

A Qinetiq blog piece about support to Royal Navy submarine operations, published earlier this year, also noted that SCYLLA is “now in use” on the ASTUTE class, but there’s no further detail currently available to the public.

Despite being developed as an AUKUS-wide capability, initially the UUV-from-torpedo-tube will only be adopted by US Navy and Royal Navy: the Royal Australian Navy assesses that it won’t be cost-effective to attempt to introduce the capability on the esisting COLLINS-class submarines.

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