The document then goes on to note many of the advanced manmade fibers that are used in these kinds of soft inflatable structures, of which Kevlar is probably the most familiar but also including Vectran, DSP (dimensionally stable polyester), PEN (polyethylene napthalate), and Spectra, a type of ultra-high molecular weight polyethylene.
“The soft structures considered for use in developing the IDSS may include, but are not limited to, control volumes constructed of inflated membranes, 3-D woven preforms, flexible bladders, coated fabrics, and hybrid (soft/rigid) material systems, and hard goods-to-soft goods connections,” the document continues. “Hybrid inflatables may include inflatable elements with semi- or fully-rigid reinforcements serving as deployment shaping controls and abrasion-resistant contact surfaces.”
Ultimately, NAVSEA may call upon interested parties to produce full-scale IDSS prototypes of their virtual design concepts that will be able to test inflation/deflation, and resistance to wave slap and impact loadings.
That, of course, is still some way off and although the document doesn’t provide any kind of timeline and the Congressional Research Service’s latest report on SSN(X) doesn’t envisage a first example of the new submarine even being procured until Fiscal Year 2031. It’s also possible that the IDSS, if it does prove successful, might only be introduced on later blocks of the SSN(X) design.
The Navy has been examining whether SSN(X) should be a follow-on to the current Virginia class design, a design based on the Columbia class SSBN, or an all-new design. Last December, The War Zone reported that the vessel would be significantly wider than the current Virginia class, making it closer to the dimensions of the advanced Seawolf class, while also utilizing technology being developed for the Columbia class.
If IDSS is successful and is adopted as part of the SSN(X) program, a further phase of the development, as envisaged by NAVSEA, would see it adapted for other potential applications, namely “future underwater weapons, unmanned underwater vehicles (UUVs), unmanned surface vehicles (USVs), and commercial/industrial dual use.”
The latter category is notably broad, encompassing lighter-than-air (LTA) vehicles, space vehicle structures and habitats, “chemical/biological containment systems for internal use aboard aircraft and mass transit ground vehicles,” and others.
It’s clear that the U.S. Navy is now looking seriously at operating future nuclear attack submarines with inflatable constructions in place of their traditional sails. While this proposal sounds like it would offer considerable advantages, on paper, actually developing a reliable technology is likely to be a much more challenging proposition. After all, if the inflatable sail fails to properly retract, for example, it would render the submarine highly vulnerable and at the very least end its mission.
However, if NAVSEA’s initiative is a success, it could permanently change the way advanced attack submarines look while making them even more effective fighting machines.
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