October 9, 2018

Saab Offers A26s for Netherlands' Walrus Submarine Replacement Program

View A. Sideview of Dutch A26 concept (Image Saab via MarineSchepen.nl)

On October 8, 2018 Anonymous reported regarding concept A26 submarines for the Netherland's (Dutch) Navy's Walrus submarine replacement program - along the lines:

Currently, Sweden's Saab and the Netherland's Damen have teamed up to offer a large concept submarine based on Saab's A26 [1].

The information on A26 may provide some insights into the concept submarine. It is likely:

1.  the pressure hull material: Strenx® 700 (proof strength, Rp0.2=690MPa).

     Using https://www.convertunits.com/from/psi/to/MPa this is equivalent to US measure HY100.
     Also see Table for Sweden's Weldox 700.
2.  Propulsion electric motor: PMSM by JEUMONT ELECTRIC (3.3MW)
3.  Four Stirling AIPs (60kW x 4 =300kW)
4,  Diesel generators: 2 x 12PA4 V200 SMDS by MAN Diesel & Turbo (total electrical output 
     2,128kW) [2]

[1] https://marineschepen.nl/nieuws/Details-voorstel-Saab-Damen-nieuwe-Nederlandse-onderzeeboot-010618.html At “a displacement of about 2900 tons, the design is slightly larger than the current Walrus-class submarine's [2,650 ton (submerged) displacement]. The concept submarine is currently about 73 meters long and has a diameter of about 8 meters. “

View B. Above is an artist's impression, of the propulsion components.
On top is the Stirling AIP motors and Diesels. 

On bottom the "tanks" for liquid oxygen (LOx) and Lithium-ion? Batteries. 
MarineSchepen.nl explains "All engines are equipped with a hood. This ensures noise reduction, but also a more pleasant working environment for the technicians. In the engine room it is a lot quieter and cooler." (Image Saab via MarineSchepen.nl)
[2]  In View B. The length of diesel module seems to be about 4.5m long - a bit smaller than MTU 12V4000U83's length of 4.58m.

View C. Closeup sideview of Dutch A26 concept. "KOMBUIS" means Galley. (Image Saab via MarineSchepen.nl).

Pete Comments

Saab and Damen have been pointing to a Walrus replacement concept since early 2015. "Kevin" has pointed to the strategic uses of Walrus submarines since 2015. 

Germany and probably France and Spain would also be offering concept submarines for the Walrus replacement program.

The Walrus upgrade program may mean the 4 Walrus submarines will remain operational up to mid 2025.

Anonymous and Pete


Anonymous said...

Hi Pete

Both A26 and LAB/AIP-Soryu equip with Stirling generator, 4V-275R MkIII. Japanese Standard for Ministry of Defense (NDS) on LAB/AIP-Soryu clearly specifys that rated output (continual) and 120% output (2min) of 4V-275R MkIII are 60 and 72kW, respectively. Then, total output of four 4V-275R MkIIIs is 4 x 60kW = 240kW.


Anonymous said...

Hi Pete (continued from 9/10/18 11:39 PM)

75kW is mechanical ouput of Stirling engine, not electrical output of Stirling generator.
Electrical output (60kW) = 0.8 x mechanical output (75kW)