Greg Merkle's Nautilus Concept

(Each of the Nautilus designs in the catalog is unique and each of the designers has a rationale for the design.  Greg Merkle provided this detailed description and explanation of his Nautilus, including the interior.)

orking primarily from the Naval Institute Press WJM/FPW translation I have developed this design for Jules Verne’s Nautilus. Due to inconsistencies in the various contemporary and later illustrations and the text, the text sourced descriptions were used. A strict reading taking into account the technology of the period I believe would

produce a design very much like an enlarged CSS Pioneer. While staying faithful to the text, some license was taken for aesthetics – producing a more organic appearance than a strict reading would produce. 

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Exterior Points of Interest:

·         The spindle shaped hull has a volume 1543.4 cubic meters – very close to Verne’s 1507.2 - with more surface area 1040.44 vice 1011.45 square meters (slight enlargement due to maintaining a smooth curvature and providing sufficient space near the bow to accommodate Aronnax’s cabin and other internal details)

·         As others have recognized a centerline mounted ram could not inflict the damage on the Scotia as described; but instead of mounting the ram on the upper part of the hull as proposed by other designers on the site, the hull at the bow and stern is deflected upwards by 2 meters. The ram itself has a triangular cross-section with a maximum width of 2 meters.

·         The topside “platform” is not a separate structure but a flattened deck as used in many modern Albacore style submarine hulls.

·         Alongside the hull are folding masts and booms and on deck two retractable winches for deploying and recovering the trawling nets referenced several times in the book.

·         At the forward and aft ends of the platform are retractable winches and mooring rings (as Aronnax testifies they used to hold on to the submarine when the party initially comes aboard).

·         The Pilot House and Beacon cupolas are of cylindrical shape for best water-tight seal. The ports of the six-lens beacon are positioned to provide all-around lighting without having a lens pointed directly toward the Pilot House. Both cupolas are surrounded by a circular grab rail attached near their peaks, slightly smaller in diameter than the base of the cupola to permit retraction below the level of the deck.

·         In the middle of the platform deck is the recessed dinghy and just aft the main hatchway.

·         Topside near the bow are two vents from which the discharge of water/air/steam was witnessed.

·         The mid-ship mounted dive planes and screw have guards to protect them from damage during ramming.

·         The oval salon windows are protected by sliding external shields.  

·         The diving chamber is accessed through the starboard side mounted hatch/boarding ladder.

·         Below the hull is a single bow anchor, gratings for the ballast tank inlets, and the dorsally mounted propeller type patent log.

·         On each side of the aft section of the hull are copper radiators for cooling the propulsion equipment.


Hull Design

Verne is very specific about the dimensions of the Nautilus and I have tried to keep this design as close as possible with minor deviations to accommodate the internal layout. The dimensions specified would result in a spindle shape also in accord with portions of the text. To perform the calculations I used Michael Crisafulli’s suggestion and divided the hull into 28 X 2.5 meter segments and calculated the volume and surface area of each, totaling the results. Using an Excel spreadsheet I was able to make various adjustments to get the desired hull curvature while staying close to the original volume. I also needed to determine how the hull was constructed as it would determine the hull thickness and interior space. After settling on a hull thickness of 15cm (see section on hull construction) I added blocks to the spreadsheet to calculate the interior width of each deck while testing various deck elevations. In order to accommodate the interior spaces described in the book I had to enlarge the hull slightly to 1543.4 cubic meters from 1507.2. Internal limitations included:

·         Width of 2.3 meters at the forward bulkhead of Aronnax’s cabin to for a 2 meter bunk athwartships

·         An interior deck width of 4 meters at the forward engine room bulkhead for the 3 meter (10ft) wide Crew’s Mess/Cell with an additional 1 meter passage to the Diving Compartment

·         Lower deck height of 2.75 meters (9ft) sufficiently high that Ned Land could not reach the ceiling of the Crew’s Mess/Cell

·         2 meter deck height on the upper deck

·         Minimum 1.9 meter height in forward cabins and passageway

·         Adequate space above the upper deck for the retracted helmsman’s cage and beacon and the socket for the dinghy without intruding into the upper deck overhead

·         Diving Compartment space for a diving chamber and prep area large enough to accommodate the required number of ready divers and diving gear storage for the underwater excursions described

During the design process the external drawings were completed before the internal layout was finalized. Certain internal features that affected the external appearance (location and size of the Salon portal, boarding hatch, dive chamber and pilot house and beacon cupolas) had to be established earlier.

Note on calculations: The numbers stated in the text appear to have been calculated using the truncated value of 3.14 for pi instead of the extended value if using a calculating program or pocket calculator. With this value a hull comprised of a center 10 meter cylinder with a 30 meter conical section on each end results in values spot on Verne’s stated value of volume and near exact for surface area with possible rounding error. For this reason I also used the truncated value in my spreadsheet calculations; the resulting deviation being insignificant.

Hull Construction

As in the section on hull design, Verne lays out very precise values for the surface area and mass of the hull. A steel hull with the surface area and thickness given would have exactly the mass described. The translation I worked from states that this is the inner hull though the original text is vague enough that it could be either. Due to the specific values stated in relation to the overall dimensions I believe Verne is referring to the external hull. Stuart Wier’s theory that Verne’s design was inspired by the Great Eastern also backs this as the double-hull construction of that ship was for structural rigidity, not as in modern submarines with a strong inner pressure hull and a thin streamlining outer hull. The second hull details are not provided but I believe it would likely have nearly the same thickness for this same reason.

Riveted construction of the time required access to both sides of the assembly. The hull would either have to have both layers spaced close enough to rivet through both hull layers and T-rail at the same time or be spaced far enough apart for a workman to crawl into the void space to back the rivet. The latter would require a hull thickness such that it would not be possible to fit the interior as detailed.  

In the attached sketches I have an outer hull 5cm thick separated by a 5cm thick T-rail frames and stringers from an inner 3.75cm thick inner hull. The assembly is through-riveted with the outer rivet tails hammered nearly flush as on the CSS Hunley for reduced drag. Rivets on the topside deck are also countersunk for a smooth walking surface as described by Aronnax on his initial boarding. The final hull thickness including the height of the internal rivet heads comes to 15cm.

Plates on the topside deck and plates on each ring segment are butt joined with the T-rail providing the joining surface. Each hull ring segment is overlapped with the segment aft. To seal the plates I propose a method I found referenced for sealing boilers – lead foil gasket material sandwiched between the plate and T-rail surfaces drawn tight by the cooling rivets.


At the time of the collision with the Scotia Nemo states that the Nautilus was cruising at a depth of 2 meters but there is no reference given. Submarine depths are usually given as depth to keel but this would result in a depth of at least 7.2 meters when running surfaced (greater if the design incorporates an external keel). Instead I interpret the 2 meter depth as 2 meters below normal surfaced trim. This places the tip of a centerline ram at a depth of approximately 5.2 meters, well below 2.5 meters where the Scotia was damaged. To correct this, the bow and stern of this design are deflected upwards by 2 meters. This places the tip of the ram at a depth of 3.2 meters. The section of the ram of maximum width (2 meters) is an additional 0.5 meters above the level of the tip resulting in the top of the puncture to be 2.7 meters below the waterline. The remaining 0.2 meters (8 inches) difference could be attributed to either variation in the depth at which the Nautilus was running or a deviation in the loading of the Scotia resulting in a draft greater than the reference draft at the time of the collision. Although not exactly the depth required, additional deflection of the hull created mounting problems with the interior layout.

The ram itself is a single large hollow steel casting incorporating the air reservoir and capped with a domed bulkhead becoming an integral part of the hull. The riveted ram/hull joint is reinforced with a steel band, a steel shield across the top of the hull providing additional protection in a collision, and joined to the forward extension of the keel.

Ship’s Boat

The ship’s longboat is stored in a recessed socket in the center of the platform as described in the book. In my initial designs I used standard davits as the means of deploying and recovering the boat but found the rotating arm equipment described on the Vernian Era page much more practical and efficient. However instead of the boat being rigidly attached and flipping in the process I have a set of pivoting bolts at the bow and stern which allows the boat to remain upright during the process similar to a Ferris wheel car. Withdrawing the bolts from the frame allows quick deployment even when still in the storage socket. The starboard view of the Nautilus in its “dirty” configuration shows the longboat at the maximum vertical point in its arc – approximately midpoint of the deployment/recovery process. Visible on the lower hull is the access hatch.

Capable of being maneuvered by minimal crew the boat favors a lightly constructed hull. Nemo even describes it as such during Aronnax’s tour. This would require that the hull be flooded when operating at depth as suggested by Greg Sharpe.

Unfortunately a lightly built boat creates plot problems. In the chapter “Bay of Vigo” Ned states that he had already stowed provisions aboard the dinghy which would have required draining the water prior to loading without the crew’s knowledge. However after this confession, in the chapter “The Sargasso Sea” the Nautilus dives to 16,000 meters which would certainly have crushed a lightly built boat drained of water. If the crew was to fill the boat as a matter of routine deep depth operations this flooding would have ruined any provisions previously stored within. In the end this proved unimportant as the provisions were unnecessary in the final escape scenario. Another risk would be that the Nautilus could have exceeded the crush depth of the drained boat while Ned was inside. My final explanation would be that the boat is lightly built and checked and flooded as SOP for deep dives but drained when coming shallow in preparation for use and Ned just got lucky.

Mooring Equipment

The mooring gear I have provided includes 5 pairs of retractable deck cleats, a folding bullnose mooring ring and retractable electric winch at the bow and stern, and a single bow anchor. The hull is also configured with an external keel and fin allowing the hull to rest level on the sea floor.

Although Nemo’s aversion to land would make much of the gear seem superfluous, it is still used during the stop at Nemo’s volcano base in the chapter “The Submarine Coal Fields”. Also in the chapter “The Torres Straight” Ned makes specific mention of using the anchor to kedge the Nautilus off the reef and that Aronnax confirms that Nemo will not use this technique and simply wait for the tide to refloat the boat but the implication is that the Nautilus is so equipped.


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Crew Complement and Accommodations

Verne provides little evidence of the crew complement other than periodic references to working party and excursion sizes. This becomes an important plot element as Ned evaluates escape options but leaves important gaps in determining crew size and accommodations. The largest party specified consists of twenty sailors but actual crew size would as a minimum include additional crew still remaining at vital watch stations. There is mention of the 5 meter crew’s quarters as well as reference to two smaller cabins: a two-man cabin that is assigned to Ned and Conseil, and the cabin near the crew’s quarters where Aronnax examines the injured crewman. From the interior layout I was able to fit in additional cabins for junior and petty officers, and one for the first officer just aft of the chart room.

The 5 meter cabin was able to fit 2 x 3-bunk stacks on the inboard wall and 2 x 2-bunk stacks along the hull (there being insufficient overhead space due to the curvature of the hull for an additional bunk) for a total of 10 bunks with several lockers for personal effects. If utilizing “hot bunking” with two watch sections there is room for 20 seamen. The four additional two-man cabins would provide quarters for two junior officers standing two-section officer of the deck and six petty officers: e.g. Quartermaster, Chef, Boatswain, Engineman, Electrician, and Coxswain. In the Dining Room I provided four chairs allowing Nemo to dine with all his officers as was customary of the time.

With the captain and first officer this totals 30 crewmen when the Nautilus first went to sea. At the time the protagonists came aboard there had been at least two crewmen lost to leave a vacant cabin for Ned and Conseil. This is confirmed when attending the funeral in the coral cemetery as there had been other crewmen previously interred at his location.

Aronnax's Cabin

Because of the limited space the furnishings are built-in instead of free standing. Due to the extreme taper, the flat floor is only 1.8 meters wide at the aft cabin bulkhead leaving only enough room for the two required doors. This left the only space for the bed as mounted athwartships on the forward bulkhead. The length of the bed set the minimum hull width as 2.3 meters at this point with 2 meters for the bunk and an additional 0.15 meters for the thickness of the hull at each side. Despite these restrictions there is still adequate space for a Twin XL size bunk, a full-height wardrobe built into the larboard side and a washstand and mid-height locker build into the starboard side. As the bunk is mounted at mid height of the forward bulkhead there is sufficient space below to stow a small dressing stool.

Nemo's Office (Cabin)

Although I had not previously considered it, I agree with Michael Crisafulli’s theory that Aronnax’s cabin was originally the Captain's sleeping quarters and this space was originally Nemo's office/workspace. This set the direction of the furnishing of this room. There is a desk and chair at the aft bulkhead, and along the starboard wall forward is Nemo's instrument board and aft built into the wall is a small settee described as a bench during Aronnax’s tour. These are the original furnishings. When Nemo vacated his sleeping quarters to Aronnax he moved a small iron bed (basically a cot) and a small washstand into this space. The additional items make for a crowded room.

Grand Salon

In order to accommodate the hull slope due to the raising of the hull line to the bow, the floor is terraced. One advantage of this is that the height of the ceiling and the forward end is still nearly 5 meters above the floor level where entering at the aft end making for a more open impression. Although the ceiling is partly covered to conceal ventilation ducting and the protuberances caused by the deck features, the walls are left bare to follow the curvature of the hull though paneled and wall papered. From the side view the amount of available wall space for hanging paintings, arms and tapestry is apparent though approximately the upper third would be unusable for this purpose due to the inward hull curvature. Initially I intended there to be sliding panels to cover the observation ports but this proved unsatisfactory as they either would absorb wall space if mounted internal to the salon or required a thicker hull section if they were to retract into the walls. I finally decided the panels would be mounted external to the hull which would also provide protection to the glass ports during collision.

At each corner of the room are panels cutting off the corners of the space. Set into each of these corner panels are recesses which contain the marble and bronze statues. On the upper terrace at the forward bulkhead is the pipe organ and stool. Behind is the "costly mosaic table". Next to that facing aft is one of the display cases built into the terrace. On the mid terrace are two divans. Though not indicated they are mounted on central pivots and swing arms allowing them to be swung out or rotated to face out the ports located immediately behind them. At the aft end of the mid terrace is a 2 meter pedestal upon which sits the clamshell fountain. The pedestal also conceals the pressure chamber containing the anchor winch and chain locker which is open to sea pressure through the chain chute and keel of the boat. On the lower terrace built into the aft side of the pedestal and on each wall are additional display cases. On the aft bulkhead is the ladder to the upper deck. Placing the ladder at this point permits Aronnax and Nemo to transit from the forward part of the boat to the upper deck passageway during their tour. It also allows Nemo rapid access to the conn from the forward areas if required. 

Pilot House and Chart Room

The Pilot House consists of a 2 meter square lower room with a movable cylindrical cell above. The cell consists of a tapered cylindrical cupola with an open basket suspended blow for the occupants to stand. The cupola slides in a guide sleeve with a seal between. Retraction and extension of the cell requires only a simple mechanical jack as the operation is performed on the surface when there is no external pressure. When in position the cell is secured from movement by a lip around the lower edge of the guide sleeve when retracted or by blocks when in the extended position. The cell is accessed by a collapsible straight ladder and hatch in the basket floor when either raised or retracted. The cell contains the ship's wheel forward, the engine order telegraph to larboard and the diving planes control wheel to starboard. Both wheels operate telescoping shafts through bevel gears through the floor of the basket to operate the control surfaces.

Aft of the pilot house on either side are panels to control the trim, drain, and ballast systems on the larboard side and to control the ventilation and air supply systems to starboard.

In the center of the chart room retracted into the overhead is the periscope (see my arguments for the existence of a periscope). Further aft is a large chart table and locker.

Electrical Compartment

The power cells described in the chapter “Everything by Electricity” are more akin to fuel cells as the chemical components are replaced as they are consumed in order to continue generating power. Compared to a primary battery where once the reactants are expended it is disposed of, or a secondary battery where the chemical process is reversed by recharging, the power can be generated indefinitely as long as sufficient replacement reactants are available and the waste products are removed from the cells. For this purpose additional equipment is installed.

To starboard is the cell conditioning equipment to extract the amalgam from the cells, remove the expended reactants, replenish the sodium, and return the reconstituted amalgam to the cells.

On the larboard side is an instrument board to monitor individual cell voltages, temperatures, and reactant levels. Also to larboard is a switchboard for isolating and bypassing individual cells and controlling distribution of electricity to the rest of the boat.

Aft are the power cells with a catwalk running between the two banks and aft to the Motor Room bulkhead. In the deck is a hatch and below a ladder to access the bilge area and the bottom drain cocks on the power cells.

Motor Compartment

For the main propulsion motor I initially considered a rotating armature type. While this type in its primitive form had been invented in the 1830s and I believe Verne would have recognized its greater potential, I decided a reciprocating design would better fit the description in the book.

In order to pack the most motor into the cramped space at the aft end of the engine room I used a radial design similar to air-cooled radial aircraft engines. The reciprocating motor uses electromagnets in four rows of fixed water-cooled stator rings with iron core slugs in place of the pistons driving connecting rods and a common crankshaft. Located at the aft end is the distributor which controls the timing of the magnets. The distributor timing is shifted to reverse rotation.

At the forward end is an open 4-speed reduction gearbox to permit the motor to operate at its most efficient rpm regardless of the shaft speed. Ships bells are answered by shifting to the appropriate gear for the bell ordered. Levers on each side operate the gear train and clutch; the gear train transferring power to the main shaft which passes below the motor and out through the shaft seals. The motor, gearbox, its operating levers and associated linkages roughly conform to the description in the related passage in the book.  

At the forward bulkhead is a board to monitor motor operating conditions and on either side are two cooling water pumps to circulate cooling water heated by the motor and power cells to the radiators mounted externally on the hull.

Crew’s Mess (Cell)

It is unlikely that a room of this size would be set aside just for a brig. The only other reasonable use as others have noted would be as the crew’s common area for dining and recreation. To comply with the text the room’s placement required having a door near the base of the central stairway and a door 10 meters from the door to the Dining Room. This places the aft wall of the room at the forward engine room bulkhead. It also required a 2.75 meter ceiling high enough to be out of the reach of Ned Land.

Diving Compartment

This compartment contains the Diving Chamber with internal hatch and external combined hatch and boarding ladder. To larboard is the Diving Locker for storage of the diving suits, helmets and breathing apparatuses. To starboard is a small arms locker for ready storage of the pneumatic guns. I wanted this area to be large enough to fit four to six divers in the prep area and another four in the chamber. The locker would also need to store sufficient number of diving suits to equip the sixteen men that participated in the funeral precession.

The Periscope

Arguments for a periscope on the Nautilus:

·         The simple periscope is credited as being invented in 1647 and the submarine periscope in 1854.

·         Optical technology of the time was advanced enough to overcome much of the image brightness and quality issues that had been experienced. Advanced multi-element optical eyepieces and objective lenses had been developed associated with astronomical telescopes by this time. It would have been an issue more of application than capability.

·         Aronnax is in the pilot house/chart room only for the transit through the Arabian Tunnel and therefore never observes how the Nautilus is navigated with the cupola retracted.

·         In a biography of Verne in regards to “From the Earth to the Moon” the author stated that Verne avoided using technology that to the public appeared immature (rockets) in favor of technology more well-known (cannon) to create a more believable story even if the former provided a superior solution. In this case I believe Verne would have included the periscope if it had been more well-known. Instead he just avoided the subject by not allowing Aronnax access to the pilot house during the attack; the only action requiring its use.

·         Although a practical rotating submarine periscope had not been developed, a fixed (non-rotating) periscope could be fabricated; using multiple tubes to view various directions.

Though not entirely impossible, a long fixed periscope that extended above the surface would still pose many issues including extending down through the library when retracted, misalignment of the mirrors due to tube flexing, longer time to retract into the hull prior to impact, and greater light loss, and excessive drag associated with a multiple tube design compared to one that extended just above the hull. A short periscope could be quickly retracted shortly before impact to prevent damage.

The periscope I have decided to use is a fixed multiple-aperture periscope similar to that used on armored vehicles covering the 180 degree forward arc. This would provide visibility not significantly inferior to the extended pilot house with the exception of vertical field of view and to the aft. The upper assembly is extended to protrude approximately 25cm above the deck and the lower assembly with the viewing ports is retracted into the overhead of the chart room when not in use. It would therefore not have been visible to Aronnax during his brief time in the room.

Bulkheads and Watertight Compartments

In the text the Nautilus is divided into four, possibly five water tight compartments. Verne specifically identifies the bulkhead between the forward cabin area and the salon, between the library and the dining room, and at the forward end of the engine room. He also alludes to another when he states the ladder to the dinghy is between two watertight bulkheads. As it is mentioned prior to entering the crew compartment it is not a reference to the engine room bulkhead. This would place another bulkhead between the dining room compartment and crew compartment. Note that these doors and bulkheads are not referred to as being watertight when Aronnax initially walks through the forward areas; it is only on his return trip through the boat that this is stated. He also states the engine room is divided “by function” into two areas but it would also be reasonable that it also be divided by another bulkhead. This would minimize the volume that could be flooded without isolation. This would also apply to the door between the library and the salon – which is also a very large volume.

Because of the low reserve buoyancy (150 tons – 10%) it would be logical to have greater subdivision in the event of flooding. I have therefore separated the Nautilus into seven watertight compartments adding the two bulkheads mentioned. I have also interpreted the “double door” between the dining room and library as two doors face to face, opening opposite each other from opposite sides of the bulkhead. This configuration would ensure that regardless of which compartment on either side of the bulkhead flooded, the water pressure would positively seal the hatch on that side without having to rely on the dogs. This is not required on modern submarine doors but would be beneficial considering the materials technology of the time and the extreme diving depths the Nautilus is capable of. I also used the double-door configuration at the engine room bulkhead. This placement as well as the direction of the doors was based on evaluating each compartment’s vulnerability to flooding and how critical the compartment was to recovering from the casualty or saving the crew.

Other Miscellaneous Details

·         The Dining Room, Library and Galley follow the book descriptions with additional details previously given.

·         At the foot of the first flight of the central stairway is the tackle locker containing the nets, blocks, and line for the trawling gear.

·         On either side of the forward upper deck are lockers for storing the sodium reserves in oil-filled canisters.

·         Ladder access to the longboat is on the starboard passageway between the first officer’s cabin and the tackle locker.

·         In addition to the arms locker in the Diving Compartment there is a larger armory in the upper gallery located near the gangway to facilitate repelling boarders.

·         The Blower Room located under the central stairway contains the ventilation air blowers and air compressors.

·         Midships under the lower deck, accessed from the Blower Room is the Pump Room containing the Trim, Drain, and Ballast Pumps.

·         A dumb waiter is located near the central stairway easily accessible from the Galley on the upper deck and the Crew’s Mess and Dining Room below.

·         The Aux Trim Tanks, Forward Trim Tank, and Aft Trim Tank constitute the additional 100 tons of ballast tankage described by Nemo.

·         A potable water storage tank is located beneath the floor of the Salon.


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