Nautilus is the second recommended destination for sailing, after Blake Sea. This continent is linked to Corsica at North, with Satori at South and with Blake Sea at South-East, with Transcontinental Channels. Together with Satori, it forms a supercontinent, like Euroasia in real workd.
In South-East, close to the connection with Blake Sea, there is Nautilus City, a city on an island, with an inner citadel, a complex road network and a navigable channel.
The continent has a complex coast line, with many gulfs and peninsulas. The road system is not well developed, with many missing parts. The coast is usually populated, while the mainland sims inside the continent, without access to road and water, are usually abandoned. The seas are usually not deep and the dryland is a plain.
Construction started on April 24th 2007, at 6 days after the construction of Satori. At November 12th 2007, Nautilus was complete and it was connected to Corsica (West channel, at Castle Valeria) and to Satori (West connection). On Octomber 17th, 2008, Nautilus City was built. An ilustrated timeline can be found here: 
Private Sims In Nautilus
When Blake Sea was too small to be a continent, it was part of Nautilus, later it become large enough to be a continent.
The transcontinental channel (see Transcontinental Channels) that separates Blake Sea from Nautilus makes even a deeper separation. A few sims named Blake Sea are West of the channel, so they are technically inside Nautilus, even if they are private-owned by the Blake Sea estate. This estate is like a state that has territories on two continents.
There are many parcels named Blake Sea even if they are on mainland that historical belongs clearly to Nautilus, even parcels that have the Blake Sea name visible from sky. Technical, they cannot be inside Blake Sea (like real life Hawaii islands, who are not part of American continent, even if they are part of the United States). The fact that some parcels share the Blake Sea name is in fact a form of economical domination from Blake Sea over Nautilus.
New sims were added to South-East of Nautilus, to form a tropical paradise, similar to many places in Blake Sea. They were created in late September and beginning of Octomber 2013. We will see if this new land will become a subcontinent of Nautilus, like Nautilus City, or will merge with Blake Sea. In that case, Blake Sea will unite with the Nautilus - Satori supercontinent. At the origin, the estate that owns the new sims once owned the Irish islands in Irish - Bonaire. This is an increase in size. Previously, there were only 17 Irish islands in Irish - Bonaire, while here, in Nautilus, 22 new sims were created.
The formation of new sims has stopped, after a few movements, in November 2013. This new land is Seychelles and is a Subcontinent.
The movement of these sims was done with a high cost and under strict conditions. Negotiations for this relocation took an year.
In April 2014, Seychelles subcontinent has increased in size to 28 or 29 sims and almost all voids inside the microcontinent has been filled.
Note: It's difficult to make a clear separation between Nautilus and Satori.
Size in sims: 864 (N-S 34, E-W 32)
Size in meters: 56.62 square km (8.70/8.19 km)
Sea sims (only with water): 172
Coast sims (direct access to water): 556
Land sims (no water): 136
Sims with road access: 112
Sims without direct access: 77
Population density: med-low
Note: Population density is high is coast sims, low in land sims and very low in water sims. The water sims are usually protected land, like in any other continent, but their percent is much higher in Nautilus.
The following Coordinates are given in sims, with the same principles used by Gridsurvey . The separation between Nautilus and Satori is not clear. Subdivisions of Nautilus Continent are not shown on any map and on no site. So, the subdivisions marked here are deduced directly from map shape. The only clear subcontinent is Nautilus City. The separation line between Nautilus and Blake Sea is more clear. The numbers below are: longitude (min - max) / latitude (min - max).
Nautilus City: 1120-1131/1047-1051
Blake Sea Crossing Area: 1123-1034/1147-1053
Satori Sea Crossing Area: 1111-1119/1047-1051
South-East Island: 1125-1131/1052-1060
South Sea: 1120-1124/1052-1060
West Sea: 1106-1119/1057-1070
Star-like Gulf: 1122-1131/1066-1072
North-West Peninsula: 1107-1119/1071-1081
Northern Shores: 1120-1137/1067/1075
East Sea (North Basin): 1132-1136/1066/1072
East Sea (Central Basin): 1126-1134/1061-1065
East Sea (South Basin): 1132-1134/1054-1060
Central Landmass: 1120-1125/1061-1072
South Peninsula: 1109-1119/1052-1056
Grid Sector: K10
It is difficult to separate the surface features of Nautilus. The ocean floor can be divided into shallw waters and deep waters. The ground can also be divided into coast transition plains, hills and mountains. In many places, the land looks similar to the South-East sims of Sansara.
The mountains have an average maximum hight of 120 meters. They are massive but accessible. Usually, they have a whiter texture that makes them visible. The mountains are sometimes similar with the hills, only the color and the altitude are different, but this is not a rule. In some places, the hills are heavilly fragmented, while the mountains are more compact.
The hills cover the largest surface of the continent and almost all the islands. Usually, their texture is green. They are more fragmented, but that not always their form. The fragmentation is usually the result of repeated terraforming. Almost vertical walls can be found on all the continental surface.
Transition plains are easy to find near the seaside. They have a special sand texture. Water enters deep inside these plains. There are many gulfs, channels and estuaries, usually modified by terraforming. The plains not smooth plains. Slopes and small hills are frequent. A special case is Nautilus City, a subcontinent that stands on a large plain with green grass texture. Nautilus City has the same altitude with Bay City in Sansara.
Shallow waters are usually near the coast. They can be easy seen on map whiter then the deep sea. They are easy to terraform.
Deep waters are usually protected land. They are important waterways. The ocean floor has the same texture, sand. On the ocean floor, submerged hills are frequent. They can be a problem for large ships. Also, vegetation is present and sometimes the fish population can be unexpected high.
Seychelles are the newest part of the continent, created in late 2013. They are a Subcontinent. Overall landscape is of a tropical beach. This land is private. It is formed of 22 sims. Land can be purchased or rented from the local estate. For more info, please visit link Seychelles Estate. These islands are made to look like the real Seychelles islands. Also the names come from real world. A traveler can have many pleasant surprises here, including surfable waves and a lot of exotic landscapes.
Also, important for Nautilus are the waterways that allow access to nearby continents, the Transcontinental Channels.
Highest altitude in Nautilus is less then 160 meters, in several places, including Sevil (153 meters).
Note: While editing the Altitude map, our drone was thrown away by entity orb teleporters many times (probably 50 times). Even if we checked the map, there still might be errors. One visible error is that Blake Sea appears on the map 2 sims away to East then its normal position. Editing altitude map for Nautilus was more difficult then any other continent.
An important feature is that, compared to any other Linden-owned continent, Nautilus has the highest percent of parcels with altitude below 40 meters. By altitude, it can be divided into two major regions: lowlands and highlands Also, waterways must be noted.
Lowlands cover a large surface. In South-West, there are a lot of low islands separated by water. Their altitude is almost always below 40 meters. Lowlands can be found also in East, where they are formed of multiple small and medium-size islands. The new Subcontinent, Seychelles, can be included into lowlands. They correspond to the transition plains.
Highlands correspond to the Nautilus mountains and hills. They are visible on the main continental land and the largest island. The altitude map shows fast altitude transitions between the shores and center of the continent, that corresponds to a high declivity. There are no large plateaus in center of dryland. Each long gulf (or estuary) is continued with a valley that ends on the central mountain range. An important feature is that there are parts of the main continental dryland where maximum elevation is a bit over 100 meters. In no parcel altitude was found to be higher then 160 meters.
Waterways are always dark blue on the map. Many sims are completely submerged, but also very low islands share the same color on the altitude map.
Nautilus City is a prefect plain, with constant altitude. The navigable channel that connects the inner citadel with the ocean is visible on altitude map. Inner citadel is elevated.
The main way of transportation must be sailing. The vast network of seas, gulfs, estuaries and fjords give easy water access to many parcels. A large oceanic surface is protected land. Even so, every avatar must have its own ship or travel underwater. Automated ships are rare and almost unknown.
Unfortunately, Waterways are highly fragmented. Navigation is very hard and split because of this. The two old Transcontinental Channels in North in fact connect only remote seas with Corsica. Only since August 27th 2014, with the construction of private Seychelles Channel, South Nautilus was finally connected with Corsica and with help of South Corsica waterways, with North Nautilus. That is very good and it's suppose to boost local economy, but still is strange that you have to go through another continent. It is like if you want to go from Egypt to South African Republic and you have to go through Australia.
Road transport is limited. The road network is composed of two unconnected subnetworks. This is a major problem for the local economy. In some places the population density is similar to places in Heterocera, but to travel, an avatar needs to go through many parcels. This is difficult, since many parcels have an entity orb that will teleport unwanted visitors or have ban lines. Continous buildings and walls resulted from terraforming are also major problems. Continental land of Nautilus needs a larger transportation system.
Total road network: 20.20 km Conventional road: 15.75 km Trails, paths: 4.45 km Off-road: 0.00 km Unconnected sectors: 2 pieces Sea access: shore, not direct sea contact Continent surface: 56.62 square km Overall coverage: 0.355 km per square km
Road efficiency index: 0.332
For Nautilus City, data is less accurate (errors of 30%, see Nautilus Network for details), but total road length is estimated at 24.00 km, more then the entire continent. However, these urban roads are very compact, unconnected with the continent and completely unused. This is why they are not included in the continental data.
Waterway efficiency index: 0.705
Total transport efficiency index: 1.037
Please note that if we measure water efficiency for Seychelles Subcontinent alone, the index is somewhere around 15, that is a very good value. If we measure it for mainland Nautilus alone, the index is around 0.4, because of high waterway fragmentation.
Nautilus is by far the champion in statistics about Land With Restricted Access. Many parcels are surrounded by ban lines from nearby parcels. Slices of Protected Land are rare (road system is unsufficient and in many places, like in West part of the continent, protected waterways are absent. In many sims, buildings are all around the coast and their ban lines block access from water to higher parcels.
Also, Nautilus is the champion in the number of entity orb teleporters. Many of these entity orbs don't give a warning message. They are highly concentrated in the North of the continent, while in South it is very easy to fly.
As a direct result, many isolated parcels, without water access and surrounded by land with restricted access, are abandoned.
 - Nautilus Ferry Service
Nautilus Network - road network
 - Second Life Wikia