Could food-saving tech extend Royal Navy submarine supplies?

Recent reports have emerged about one of the CASD submarines running low on food supplies, with the crew having to share sweets and other items from the NAAFI.

To those unfamiliar with how ships and submarines are resupplied, it could seem as though these submariners were being deprived of food.

As highlighted by Rear Admiral Dr Chris Parry, when a ship or submarine departs for deployment, it typically carries around ninety days’ worth of supplies. Surface ships can be resupplied while underway using Royal Fleet Auxiliary (RFA) ships and other allied auxiliaries.

However, sometimes a port call is necessary. Resupplying a submarine at sea, on the other hand, is much more challenging and hazardous. Submarines struggle to maintain position alongside auxiliaries, so a vertical replenishment (VERTREP) is the next best option.

This article is the opinion of the author and not necessarily that of the UK Defence Journal. If you would like to submit your own article on this topic or any other, please see our submission guidelines. 

However, this method has its challenges if the vessel is in open water. VERTREP requires the fore or aft hatches to be opened, a significant safety risk.

This is realistically only feasible in very calm, sheltered waters; otherwise, there is a risk of flooding. Given the vast and largely undisclosed patrol areas of CASD submarines, VERTREP is likely not used, as it would compromise the mission.

Did Food Run Low?

When at sea, food stocks inevitably diminish over time. Fresh produce lasts only around two to three weeks before the crew switches to canned and frozen products. This is unsurprising—anyone who does a weekly shop knows that fresh products don’t last as long as canned or frozen goods. Submarine and ship menus are somewhat static to maintain a sense of normalcy; for example, on one boat, curry night was on Wednesdays, fish and chips on Fridays, and there was a ‘fallout menu’ at the start of deployment.

As supplies dwindle, food items may be rationed, a decision made by command and logistics teams. Rationing could mean something as simple as serving only one sausage with breakfast instead of two, stretching the stores to make them last longer. Low food stocks are not uncommon on ships or submarines. However, some allied navies employ a method to alleviate this issue, which the UK has trialled.

Another Method

In 2011, on HMS Turbulent, celebrity chef Heston Blumenthal demonstrated that essential supplies could be condensed using the sous vide method. He showed Commander Ryan Ramsey the vast amount of food required for a single meal for the crew, which took up an entire mess table seating up to six. The same ingredients prepared sous vide occupied only a large box.

One of the significant issues for submarines is storage space, so Commander Ramsey immediately saw the sous vide method as a way to extend time on station. A report was then forwarded up the chain of command to the head of logistics. However, at that time, the concept wasn’t warmly received and was eventually shelved.

What is Souse Vide?

Sous vide, a French term meaning “under vacuum,” is a cooking method where food is sealed in airtight bags and then immersed in water or steam maintained at a precise, low temperature for an extended period. This technique preserves the food’s natural moisture, flavour, and nutrients, resulting in consistent, high-quality meals. Because sous vide condenses ingredients into smaller packages, it enables more efficient storage—making it particularly advantageous in confined environments like submarines. This method also extends the shelf life of food, allowing it to be stored for longer without compromising quality, which is ideal for long deployments where space and freshness are limited.

Is Sous Vide Practical?

In short, yes. Various navies now use this method to reduce the bulk of supplies, enabling extended deployments. By decreasing the volume of foodstuffs, it’s possible to increase the overall amount carried, thereby lengthening the time on station. In his demonstration, Heston Blumenthal showed that it wouldn’t be impractical to double the stored provisions on a submarine. Thus, a typical ninety-day stock could stretch to one hundred and eighty days, or even more with rationing.

The logistics team’s priority is to maintain a balanced diet and ensure there’s enough food to go around. NAAFI items, such as sweets and luxuries, aren’t their main concern; keeping the crew well-fed is.

Many navies use sous vide on their submarines, so it’s not far-fetched to assume it’s applied on ours in some capacity. To most of the crew, sous vide food would be indistinguishable, as the method preserves ingredient integrity; the only noticeable difference might be reduced portion sizes.

Overall, sous vide has proven to be a practical solution for the ongoing challenge of extended patrols, enabling a crew to remain well-fed without requiring resupply.