Composites Essential for TKMS & SAAB Subs

Composites are essential for submarines due to their non-magnetic nature, light weight, ease of shaping and many other benefits (below). Lightweight makes for a lower displacement, not top heavy with less contervailing need for ballast. Composites are easier than steel to shape. 

So a submarine making company skilled in composites has economic-sales advantages over  one that has a greater percentage of steel in its sub.

Following this composites article Anonymous's February 8, 2021 comments led to the following:

1.  TKMS uses SIEMENS composite materials technology:

Composite materials are seaworthy and offer many benefits. First, they stand up well to the harsh and salty marine environment, resisting any corrosion while possessing much better aging capabilities than metals. Composites also provide the ability to “design the material” by combining fibers and resins in different ways and by placing the fibers along preferred orientations following loading and stress paths, thus reducing the weight-tostrength and weight-to-stiffness ratios.

Further, composites facilitate the manufacture of seamless, complex shapes for better hydrodynamic performance and stealth characteristics. Composites can be more easily draped over round surfaces while sheet metals cannot. They also enable part consolidation and part count reduction using resin transfer molding or co-curing of large assemblies at once, without the need for riveting or joining small parts together, thus reducing manufacturing cycle times and costs.

Composites also offer some valuable mechanical properties, including better fatigue resistance and less sensitivity to crack propagation than aluminium and other metals; enhanced acoustic transparency for improved sonar transmission (for instance, in the bow dome); and reduced lifetime and maintenance costs compared to metallic structures.

This photo shows the dividing line between where composites (top) and metal (the hull) have been used on this class 212 submarine. Oddly in the photo the red, white and blue bunting does not suggest it is a 212 for the German Navy or a 212-Todaro for Italy.  TKMS/HDW is using Fibersim to design and manufacture the complete upper deck, keel covers, tower sail fairings, propeller blades and rudders. (Photo courtesy SIEMENS.)
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HDW [part of TKMS] is using Fibersim to design and manufacture a variety of glass fiber and carbon fiber outfitting parts...TKMS is using Fibersim to design and manufacture the complete upper deck, keel covers, tower sail fairings, propeller blades and rudders. “Fibersim takes a lot of the worry out of the process by enabling us to capture many more details of the final composite layups...” complete upper deck, keel covers, tower sail fairings, propeller blades and rudders. In the near future, TKMS expects to extend the use of Fibersim to include the design of structural parts, starting with a new, lighter weight storage rack for torpedoes.

“Fibersim enables us to do a faster conversion from metal to composites, and minimizes the risk by verifying information before it ever gets to the manufacturing floor”.
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2.  SAAB may have its own composite material section.

[Pete comment - although SAAB buying GKN Aerospace’s Applied Composites AB Business may be more SAAB-aircraft oriented than marine.

SAAB certainly has an extensive marine composites capability, as seen in the Visby corvettes. a capability which would extend to the A26 submarines.]

Maybe SAAB and Naval Group could send comments with some details of their submarine composites?
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3.  ADifferent types of composites include:

-  Glass/carbon fiber reinforced plastic/polymer (GFRP/CFRP) and

-  Fiber reinforced metal (FRM) Metal matrix composite (MMC) for pressure hulls seems to be difficult.
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PETE COMMENT

The percentage (by weight) of composites in submarines is likely to increase across submarine makers and their country customers. 

Composites in pressure hulls (hitherto Steel or Titanium monopolies) may be possible in the future.