The sea level was once 100m+ lower, rising to todays levels between 18000 and 5500BC. Recent evidence suggests the area in the North Sea, once landmass we now call Doggerland, was densely populated, possibly with cities.


If we wanted to do a large scale investigation, what would be the best method?

I have been envisaging the production of very large, bottomless concrete boxes that can be floated to the sites, have air released from inside so they drop to the floor.

I don't know whether water pumps will be needed to constantly pump water from the edges or if it is possible to seal the edges to allow the floor inside to be made reasonably dry.

The North Sea is notoriously rough, so the boxes need to be sturdy, possibly many dropped next to each other for support.

I don't know if the top of the box should be open above the sea level, or roofed below, under high air-pressure.

The boxes could have internal reinforced struts, ideally to allow them to be 1,000,000m3

Can anyone advise on the problems that could be faced, or if there is a better alternative?

EDIT: Another option I've imagined is a gigantic frame of metal pipes that could freeze the water immediately next to them, building ice-walls over a period of time. It is salt water and moving, so may not be possible at all. And ice floats, so the whole frame would need to be strongly secured to the seabed.

I'm actually limiting the realms of possibility to the 100m3. Originally, I was trying to devise a method to reclaim some area miles across. This could be Atlantis, after all.

EDIT2: @Molot has pointed out that the engineering idea I have been imagining already exists in some forms and is called a Caisson

  • $\begingroup$ I don't have an answer for this, but I just wanted to point out that a lot of work had to be done on the way concrete reacts with water (this was done in the early 90s) I'm just concerned you'd need fairly thick walls, at which point your container would be quite heavy $\endgroup$ – Bee Jun 6 at 9:12
  • $\begingroup$ @Bee Yes. I was thinking very thick, but I know that in The Netherlands they build hollow concrete ballasts for floating houses, which gave me the idea. So long as there is enough air cavity, thick walls can be supported. $\endgroup$ – Philip Thomas Jun 6 at 9:27
  • $\begingroup$ My issue was in that you were asking about floating the concrete blocks down into place. I wasn't sure how easy this would be with the weight. $\endgroup$ – Bee Jun 6 at 9:29
  • $\begingroup$ Have you checked Diving Bells and their possibilities? $\endgroup$ – Khris Jun 6 at 9:36
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    $\begingroup$ You described en.wikipedia.org/wiki/Caisson_(engineering) - have you read about that> If so, how can you not know main challenges already? -1 for lack of own research. $\endgroup$ – Mołot Jun 6 at 10:38

When building bridges, foundations are excavated by putting concrete walls, joining them and draining the water. enter image description here

This method could arguably be adapted for working in the sea, and probably will be less destructive than dropping a box of concrete over the area.

A similar method was used to build the Hibernia platform, an offshore rig that is 80m tall... but sits at sea level :)

  • $\begingroup$ That is just the kind of thing, but on a smaller scale. That looks to be about 20-25m high. I was looking for a practical way to achieve the same with containers 100m high and 100m wide. The size is important because undersea archaeology could be hit and miss.I thought floating ready-made containers into place would be the best option to avoid piecing together in very rough waters. $\endgroup$ – Philip Thomas Jun 6 at 10:21
  • $\begingroup$ In your picture the walls are steel, like designingbuildings.co.uk/wiki/Sheet_piles $\endgroup$ – Borgh Jun 6 at 10:26
  • $\begingroup$ this does not address the question of should you excavate in this way. $\endgroup$ – John Jun 6 at 10:38

You can but you shouldn't.

You will be destroying a lot of artifacts, many materials that can be preserved underwater will not take drying out well, underwater sites often have BETTER preservation than on land. Which is why modern archeologists often excavate underwater sites entirely underwater. your boxes will allow large areas to dry out before scientists can get to the artifacts, destroying many of them.

guides to underwater excavation of historical sites.

source 1

Source 2

Source 3

  • $\begingroup$ Then, perhaps a shallow level of water could be kept, allowing archaeologists to wade around? $\endgroup$ – Philip Thomas Jun 6 at 10:40
  • $\begingroup$ @PhilipThomas That might work if the ground were perfectly flat and level down there. $\endgroup$ – We are Monica. Jun 6 at 10:46
  • $\begingroup$ @PhilipThomas dropping and setting the bulwarks will disturb a lot of material, the less you have to disturb the area the better. Bulwarks are not just restin on top of the sediment they are sunk into it. $\endgroup$ – John Jun 6 at 19:23
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    $\begingroup$ @PhilipThomas honestly archeologists would rather put up with working entirely underwater in a submarine than lose data and artifacts by using a poor collection method. I am a paleontologist and we haul several hundred pound rocks miles down mountains by hand just to lower the risk of breaking them. Scientist tend to have very high tolerances to "pain in the assness" when it comes to studying the things they love. $\endgroup$ – John Jun 8 at 4:32

If want to go fully Schliemann and destroy what you are researching, just build a ginormous ring of dykes around the Doggerbank ahum, now Doggerland. The land will fall dry, destroying much of what you want to research. But, at least you can do it without all those pesky robots and diving gear...

*Reclaiming land this way is not as easy as this answer makes it out to be...

  • $\begingroup$ I was hoping to target a small area a few km2 . Would a shallow level of water left within a ring of dykes be a safer solution? $\endgroup$ – Philip Thomas Jun 6 at 11:38
  • $\begingroup$ A shallower area would solve some problems, but is still very destructive to the environment you are researching. So, yes, safer for the researchers not to the artifacts. Best bet is to go with @John and use remote operated robots and divers. It is actually not that deep there. $\endgroup$ – Flummox - don't be evil SE Jun 6 at 11:52
  • $\begingroup$ Sorry, I meant that the 100m+ high dykes in a circle a few km wide would keep the inside at seabed level, but pumps could ensure that the seabed is never dry, but always under about 18" of water. I thought the shallow water would still protect the artefacts even if it they are no longer under a high pressure. $\endgroup$ – Philip Thomas Jun 6 at 12:02
  • $\begingroup$ Yes, that is true for the artifacts within the dykes But where you build the dykes, and where you get the material from, will not be kind to artifacts. $\endgroup$ – Flummox - don't be evil SE Jun 6 at 12:08

Can anyone advise on the problems that could be faced

OK, this may seem a little weird but your biggest problem is likely to be lawyers and governments.

There are a gazillion laws in multiple national and international courts that you'll be colliding with. Some of these laws involved countries and organizations with competing legal claims over the rights to particular areas. Just getting permission to go ahead would be difficult and time consuming.

Once someone hears you are trying to dig up an ancient site your problems start Big Time.

Every environmental group and archeological and historical group on Earth will focus their attention on you. Many will try and stop you. Some will try and control you. Some will be their just to argue with the other (their are turf wars in all of these fields).

I've seen legal arguments over dig sites no bigger than a small back garden go on for decades.

Your site will also have to be policed, and in this case that's going to involve you with the military of multiple governments.

The North Sea is also the "hunting ground" of major oil companies and they're not going to want you doing anything that could interfere with their claim on potential oil and gas fields in or remotely near existing fields. These guys have legal teams that make banks look shy and reserved about court action.

This is the kind of idea that you could solve very technical and financial problem for and never get off the ground simply because you'll be dead before the court cases are over.


A major challenge would be the pressure and weight of water. At 100 meters deep, it is 110 tons per square meter (or 11 kg per square cm). If your contraption sits at the ocean floor, there will be a lot of pressure to force the silt into the air-filled room. You would need to dig the edges deep down into the bedrock at the bottom of the sea to avoid this.

Addendum: Pressuring the room to 11 atmospheres could solve the structural problem. Then, however, another problem occurs: Having scientists operate under this pressure. You cannot breathe normal atmospheric air at this pressure. You would need to fill the room with a breathing gas mix, e.g. a helium/oxygen mix, with a careful balance between heliumn and oxygen to avoid oxygen toxicity. You would need to constantly clean the air of exhaled carbon dioxide and any gases that might seep from the ocean floor.

In addition, there are a number of hazards associated with high-pressure environments, including pressure differences between the air in the skull and the air in the environment during descent. During ascent, risks of getting the bends is a very serious problem, and scientists would have to spend hours decompressing after spending time below. Pressure sickness may also be an issue (as seen in the movie The Abyss).

A better solution is probably remote-controlled robot drones with tools (arms, drills, pumps) to excavate the bottom.

  • $\begingroup$ This could be countered using a roofed box, I thought. It would be pressurised with chambers for entry/exit on the top. The roof would also keep enough air inside to allow it to be floated into position before valves control decent. $\endgroup$ – Philip Thomas Jun 6 at 10:36
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    $\begingroup$ That doesn't resolve the problem of the pressure forcing water, silt, sand, and even rock under the sides of the box. Or that the 100x100 m roof of the box should be able to withstand a weight of 1.1 MILLION tons. $\endgroup$ – Klaus Æ. Mogensen Jun 6 at 10:40
  • $\begingroup$ If the pressure in the box is the same, why would the water, silt etc.. still be pushed under? If the figures show that a 100m roof with supports could not contain the air pressure, perhaps another design is possible: domed roof, cone shaped container? @Stormbolter 's example shows it working well for maybe 25m with only thin steel walls. $\endgroup$ – Philip Thomas Jun 6 at 10:48

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