M23 Submarine

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M23 Submarine

Flag Italian company M23 S.R.L. is building two submarines for the Qatari Emiri Navy (QEN). Although it has been alluded to in announcements relating to the larger Italian naval deal with Qatar, details have only slowly come out. At the time of writing the exact model of submarine has not been revealed. However, the hints have combined to paint a decent picture (see artist’s impression above).

The deal was originally reported in February 2020 as relating to Italy's main defense shipbuilder, Fincantieri. A MoU (memorandum of understanding) was signed with Fincantieri in January mentions the "the supply of cutting-edge naval vessels and submarines."

It has since been reported, in export related documents, at EUR 190 million. This covers two submarines and a training system. I suspect that some level of training and ongoing support may also be included. Significantly M23 S.R.L. is mentioned instead of Fincantieri.
GSE M23 submersible- Covert Shores

The design is described as MIDGET AUTONOMUS SUBMARINE P / N M232017023. There may be a strong hint in this number, and also the company’s name: it may be 23 meters long. We can also infer that it was designed in 2017. It is known to have a 200 kw diesel engine, 70 kw electric motor and sonar.

M23 S.R.L. is based at a factory in Ciserano, Bergamo, Italy. This exact site was previously the location of GSE Trieste, a highly regarded Italian submarine builder. M23 is a recent spin-off of GSE and has been reported as having 22 employees. The new company is associated with Qatari entities.

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GSE (Giunio Santi Engineering S.R.L. ) has a long tradition of small submarine construction. GSE stands for Giunio Santi Engineering, named after its founder and noted naval architect. In the 1980s, when the company was called Maritalia, Santi was building AIP (air independent propulsion) mini-submarines. He developed a unique tubular construction known as Gaseous Oxygen stored in the Toroidal pressure hull (GST). This consisted of steel pipes formed into a circle and then welded together to form the hull. This was both cheaper and more versatile than traditional construction.

The best known submarine with GST construction was the 3GST9. This 9.5 meter (21 ft) long boat gained a certain amount of attention as a potential Special Forces transport. Today we would call it a Dry Combat Submersible (DCS). Like so many promising designs of that era the end of the Cold War appears to have dashed its prospects.

Santi sold the GST technology to Fincantieri who marketed larger designs using the method. The 1990s were a poor time for submarine orders and no units were sold.

By the 2000s Santi’s firm, now GSE Trieste, was selling luxury minisubs to the mega-rich. They were also designing military types and some of there designs did end up in the peripherals of Navies. One design, the VAS 525 SL Mk2, was supplied to a Venezuelan oil company in 2006 and may have since found its way into the Venezuelan Navy’s fleet around 2015.

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More notable is the Button 5.60 Dry Combat Submersible which was tested by the US Navy. While very compact, potentially small enough to fit inside a Dry Deck Shelter (DDS), it retained Santi’s signature teardrop form with no sail.

M23 S.R.L. are not the only Italian company involved in the deal. On May 17 CABI Cattaneo, another Italian small submarine builder, revealed at an Italian parliament hearing that they are collaborating on two submarines for a foreign customer. While not explicit, this matches the Qatar deal. They showed an illustration of a submarine which generally matches GSE’s linage. It is missing the screw (propeller) and any sign of hatches or masks on the casing. However this gives us a pretty good idea of the overall form.
GSE M23 submersible

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