Replacing the Subs

[Halifax Tar]

Are there penalties for not meeting delivery dates?

Ask Irving.

 

[Cloud Cover]

Ask Irving.

Based.

 

[KevinB]

Ask Irving.

Or Sikorsky…

Some contracts have max damage amounts. So there is no incentive to push past a point (of failure).

 

[Maxman1]

Ask the crew and passengers on the Hindenburg ?

 

[Cloud Cover]

Or Sikorsky…

Some contracts have max damage amounts. So there is no incentive to push past a point (of failure).

Almost every contract has limitations of liability.
Specific Performance is what you want….

 

[Czech_pivo]

Almost every contract has limitations of liability.
Specific Performance is what you want….

I like the idea of the CEO and Sr Mgmt sailing or failing with the vessel/aircraft after a major refit.

 

[stoker dave]

From what I have gleaned on the "Father of the USN Nuclear Sub Force" Rickover could be a dick BUT when you're dealing with nukes.....being a dick is what is needed

I work in the nuclear industry and have worked with quite a number of individuals who have come from the US Navy nuclear program. They were, all of them, excellent workers and extremely knowledgeable.

The US nuclear navy program has an excellent history of performance. US navy reactors have a stellar record.

One of the keys to that success is strict procedural compliance. Procedures drive everything. Everything that is done is done based on a documented, reviewed and approved procedure. If a situation is encountered not covered by procedure, no one is permitted to come up with a work-around or improvisation. No one (not even the CO) has the authority to deviate from procedures.

 

[OldSolduer]

I work in the nuclear industry and have worked with quite a number of individuals who have come from the US Navy nuclear program. They were, all of them, excellent workers and extremely knowledgeable.

The US nuclear navy program has an excellent history of performance. US navy reactors have a stellar record.

One of the keys to that success is strict procedural compliance. Procedures drive everything. Everything that is done is done based on a documented, reviewed and approved procedure. If a situation is encountered not covered by procedure, no one is permitted to come up with a work-around or improvisation. No one (not even the CO) has the authority to deviate from procedures.

I am not a nuclear expert - far from it - but there are some procedures you don't mess with. I reckon you don't make things up as you go...

 

[Underway]

I work in the nuclear industry and have worked with quite a number of individuals who have come from the US Navy nuclear program. They were, all of them, excellent workers and extremely knowledgeable.

The US nuclear navy program has an excellent history of performance. US navy reactors have a stellar record.

One of the keys to that success is strict procedural compliance. Procedures drive everything. Everything that is done is done based on a documented, reviewed and approved procedure. If a situation is encountered not covered by procedure, no one is permitted to come up with a work-around or improvisation. No one (not even the CO) has the authority to deviate from procedures.

 

[GR66]

Here's a report on a new, unknown Chinese submarine type being launched:

New Mystery Submarine Signals China’s Rapid Undersea Expansion

China is launching submarines at a pace unmatched by any other nation. Its latest design, a distinctive and innovative vessel that dispenses with the traditional sail, marks another step in the evolution of an increasingly capable and technologically advanced submarine force. With little...

www.navalnews.com

I put it in this thread because of this interesting section:

Questions remain regarding the new submarine’s role and propulsion. For the latter, a standard nuclear propulsion seems most likely given the boat’s size. If it is conventionally powered, then it is by far the largest conventional boat afloat anywhere in the world. China has also been developing a smaller ‘nuclear AIP’ propulsion where a low-power reactor acts as a form of air independent power (AIP). This is similar to other forms of AIP, Stirling generators and fuel cells, but likely offers greater power and effectively unlimited endurance. The first nuclear-AIP submarine, the Type-041 Zhou class, was launched at the Wuchang Shipyard in Wuhan in 2024. It is possible that the same concept is used in the new boat, although this seems less likely than traditional nuclear power.

That reminded my of the research in the 80's at RMC about the idea of using AECL's SLOWPOKE reactor in the Oberon-class subs to charge the batteries of the subs.

A Canadian Hybrid Submarine Design: A Case for the Slowpoke-2 Reactor – Canadian Naval Review

David Dunlop, 28 February 2020. Nuclear propulsion of submarines is ideal for long distances and extended under-ice missions. But is there a better, more affordable and collaborative way? Off-the-shelf air-independent propulsion (AIP) submarines such as the French Barracuda Block 1A class being...

www.navalreview.ca

Flash forward to today with the fact that we are possibly going to be purchasing South Korean submarines and that South Korea has announced their intention to develop their own domestic nuclear submarines. What if we were to partner with them by providing the SLOWPOKE reactors to power hybrid AIP submarines?

I asked ChatGPT to "Provide a summary of the advantages and disadvantages of using a SLOWPOKE reactor to run a sterling engine in a hybrid nuclear-assisted AIP submarine" and this is the response:

Summary: SLOWPOKE Reactor + Stirling Engine in a Hybrid Nuclear-Assisted AIP Submarine​

The concept is a small nuclear reactor (such as a SLOWPOKE-derived design) providing continuous heat to one or more Stirling engines, which generate electricity to power the submarine's hotel loads and recharge batteries. The batteries then supply propulsion power as needed.
Conceptually:
Reactor → Stirling Engine → Generator → Batteries → Electric Motor
This is fundamentally different from a conventional nuclear submarine:
Reactor → Steam Plant → Turbine → Propeller
and also different from conventional AIP:
Diesel Fuel + Oxidizer → Stirling Engine → Batteries → Motor

---

Advantages​

1. Extremely Long Submerged Endurance​

The biggest advantage is endurance.
Unlike conventional AIP systems, a reactor does not consume stored oxygen or fuel.
As long as:

• reactor fuel remains available,
• food supplies last,
• maintenance requirements are met,

the submarine could remain submerged for months.
This approaches the endurance benefits of a true nuclear submarine while using a much smaller reactor.

---

2. Very Low Continuous Acoustic Signature​

A small reactor operating at constant power can be quieter than:

• diesel generators,
• snorkeling operations,
• large naval steam plants.

Stirling engines are inherently smooth-running compared with turbines and reciprocating diesels.
Potential benefits include:

• reduced machinery noise,
• fewer moving parts,
• lower vibration levels.

This could make the vessel exceptionally quiet during patrol operations.

---

3. Elimination of Snorkeling​

A conventional diesel-electric submarine must periodically raise a snorkel mast.
Snorkeling creates:

• radar signatures,
• infrared signatures,
• visual detection opportunities,
• acoustic emissions.

A nuclear-assisted AIP boat could potentially eliminate snorkeling entirely.

---

4. Improved Battery Management​

The reactor provides continuous charging.
Benefits include:

• batteries remain near optimal charge levels,
• reduced deep-discharge cycling,
• greater operational flexibility,
• improved readiness for high-speed maneuvers.

---

5. Lower Reactor Power Requirements​

A conventional SSN requires a reactor capable of producing large propulsion power.
A hybrid design only needs enough power to:

• cover hotel loads,
• recharge batteries,
• support low-speed propulsion.

This could reduce:

• reactor size,
• shielding requirements,
• engineering complexity.

---

6. Potentially Lower Acquisition Cost​

Compared with a full nuclear submarine:

• smaller reactor,
• smaller steam plant (or none),
• simpler propulsion architecture.

In theory this could lower procurement and maintenance costs.

---

Disadvantages​

1. Limited High-Speed Capability​

This is the biggest operational drawback.
A small reactor cannot sustain high-speed transit.
For example:

Mode	Power Need
Silent patrol	tens to hundreds of kW
Transit	hundreds of kW to several MW
Sprint	5–20+ MW

The reactor can recharge batteries slowly, but high-speed operations still consume stored energy.
The submarine remains fundamentally battery-limited during combat maneuvers.

---

2. Heat Rejection Challenges​

Every watt generated eventually becomes heat.
A 10 MW(th) reactor might produce:

• 3 MW electrical output,
• 7 MW waste heat.

That heat must be transferred into seawater.
Problems include:

• thermal wake generation,
• infrared detectability near the surface,
• cooling system complexity.

This is one of the hardest engineering problems.

---

3. Nuclear Regulatory Burden​

Even a small reactor introduces:

• nuclear safety requirements,
• specialized training,
• reactor maintenance infrastructure,
• fuel handling procedures,
• political considerations.

Many countries that operate conventional submarines are not equipped to support nuclear-powered vessels.

---

4. Shielding Weight​

Even a small reactor requires shielding from:

• neutron radiation,
• gamma radiation.

Shielding can be heavy and may reduce:

• payload,
• battery capacity,
• internal volume.

This challenge becomes more significant as submarines become smaller.

---

5. Lower Peak Power Than a True SSN​

A nuclear attack submarine can sustain:

• high speed indefinitely,
• rapid repositioning,
• continuous pursuit operations.

A SLOWPOKE-assisted submarine cannot.
It gains endurance but not the sustained power of an SSN.

---

6. Development Risk​

No navy has fielded an operational submarine using:

• a SLOWPOKE-derived reactor,
• Stirling-electric nuclear AIP architecture.

Potential unknowns include:

• reactor-Stirling coupling,
• long-term reliability,
• maintenance requirements,
• acoustic behavior,
• survivability under combat conditions.

Significant development and testing would be required.

---

Strategic Assessment​

A SLOWPOKE-Stirling hybrid would occupy an intermediate position between conventional AIP submarines and nuclear attack submarines.

Characteristic	Diesel-Electric	Nuclear-Assisted AIP	SSN
Months submerged	No	Yes	Yes
Sustained high speed	No	No	Yes
Requires snorkeling	Yes	No	No
Reactor complexity	None	Moderate	High
Acoustic stealth	Very good	Potentially excellent	Good–excellent
Strategic range	Moderate	High	Very high

The concept's strongest selling point is that it could deliver SSN-like endurance and stealth without requiring the large reactor plant of a traditional nuclear submarine. Its main limitation is that it would still rely on batteries for high-power propulsion, so it would not achieve the sustained speed and power projection capabilities of a true nuclear attack submarine.

 

[Cloud Cover]

Re: item 2, would such a vessel be a fairly easy target to passively detect by satellite?

 

[PHughes]

That is a tremendous amount of engineering to get 20kW of output

The 4th Gen AIP system on 212CD puts out close to 450kW.

RUMINT says the 212CD carries enough AIP fuel for 40+ days submerged so getting up to a Max Crew Mission Endurance range of 70 days would be a “stretch the boat to add more AIP fuel engineering challenge” rather than add a nuclear reactor engineering challenge

Which has already been studied . . . the Type 212 CD E proposed for the Dutch navy.

 

[Maxman1]

Here's a report on a new, unknown Chinese submarine type being launched:

New Mystery Submarine Signals China’s Rapid Undersea Expansion

China is launching submarines at a pace unmatched by any other nation. Its latest design, a distinctive and innovative vessel that dispenses with the traditional sail, marks another step in the evolution of an increasingly capable and technologically advanced submarine force. With little...

www.navalnews.com

Are there any theories on why it lacks a fin?

 

[SeaKingTacco]

Are there any theories on why it lacks a fin?

Lowers the active sonar return?

Perhaps it is a UUV, so no need for periscopes?

 

[GR66]

Lowers the active sonar return?

Perhaps it is a UUV, so no need for periscopes?

Could you use compressed air and a kevlar tube to have an inflatable periscope?

 

[Good2Golf]

Could you use compressed air and a kevlar tube to have an inflatable periscope?

No need, trail it out on a line to ascend, and surface with a stabilized low-profile gimbal.

 

[oldcpu]

Re: item 2, would such a vessel be a fairly easy target to passively detect by satellite?

Unlikely IMHO. Geostationary satellites, which can view part of the earth continuously, at 40,000km are far too distant to have the necessary resolution and sensitivity (given cloud layers they must penetrate).

So one is then required to use Low Earth Orbit (LEO) satellite orbits, which means a massive number of satellites to have a reasonable degree of both detection and tracking. Thus far, massive large satellite constellations are nominally only seen in communication satellite constellation such as Starlink, and even there, the satellite altitude distances (~550 km) are very very distant for expecting a sensor to have a useful resolution.

The above assumes a sensor would be capable of discerning heat put into the water by the submarine prior to such heat being dissipated by the ocean. LEO satellites, like GEO, may have too many cloud layers blocking their thermal view of the water, even if the ocean dissipation of heat was slower than desired for submarine safety. Its a very difficult task to detect (much less track) an underwater object from a satellite, and I venture a guess that even with assistance from AI, the information is simply too diffuse and intermittent to make such reliably possible.

 

[SeaKingTacco]

No need, trail it out on a line to ascend, and surface with a stabilized low-profile gimbal.

That was my other thought- that any sensors/antennae needing to go to the surface are on cables.

Or, there are traditional sensors, but the PLAN, just decided to use up much of the space below it.

So- maybe it is a really large UUV?

 

[GR66]

So- maybe it is a really large UUV?

At 120m that would be one hell of a large UUV. Boeing's Orca XLUUV is 26m and the RN's XV Excalibur is only 12m. China had a rumoured one in the 40-42m size but this would be 3 x the size of even that.