# tunnel between Anguilla and Saint Martin



## islander10 (Mar 29, 2013)

Hello, I want to know if is possible to construct an underwater vehicles tunnel between the islands of Anguilla and Saint Martin/Sint Maarten in the Caribbean.

I only mean from an " engineering/geological" angle, not an " economic" angle. 

I checked the geography, and the shortest part of the Anguilla Channel is 7 kilometers long ( 4.3 miles) and the deepest part would be 12 meters deep. 

Anguilla is reportedly made of coral and limestone, i don't know if this would be strong enough to keep the tunnel.

anyone with knowledge about this underwater tunnels can comment?

thanks


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## NordikNerd (Feb 5, 2011)

islander10 said:


> Hello, I want to know if is possible to construct an underwater vehicles tunnel between the islands of Anguilla and Saint Martin/Sint Maarten in the Caribbean.
> 
> I only mean from an " engineering/geological" angle, not an " economic" angle.


Only 7km and 12m depth. I presume a bridge would do here. The Öresund bridge is 7,85 km.


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## islander10 (Mar 29, 2013)

NordikNerd said:


> Only 7km and 12m depth. I presume a bridge would do here. The Öresund bridge is 7,85 km.


 yes, a bridge would be easier to build, and even much more economical,but it would be an eyesore over the channel. It would look ugly. 

Keep in mind that these two islands are tourist attractions, they sell the beauty of their nature. A bridge would ruin that. That's why is best going underground, the views of nature wouldn't get disturbed.


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## sul_mp (May 28, 2007)

I'm sorry, but since the deepest part is only 12m, wouldn't the tunnel be visible?


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## islander10 (Mar 29, 2013)

sul_mp said:


> I'm sorry, but since the deepest part is only 12m, wouldn't the tunnel be visible?



no, the tunnel would be about 9m below the bottom of the channel(12 m below sea level) . That is, the tunnel would be about 21 m below sea level. Which is not that deep.


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## Clery (Dec 5, 2010)

Both islands are 100 km² each. Anguilla has a population of 13,000 and Saint-Martin 75,000.
I know you've put economical considerations aside, but still!


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## islander10 (Mar 29, 2013)

Clery said:


> Both islands are 100 km² each. Anguilla has a population of 13,000 and Saint-Martin 75,000.
> I know you've put economical considerations aside, but still!


 From the economical considerations, keep in mind that this tunnel would be very short compared to other tunnels around the world, let's say the " Chunnel" between UK and France, with an underwater portion of about 35 km and the deepest being 50 meters.

Anguilla is 13,000 residents, and going thru economic hardships, one reason they think is to blame for that, is because their population is too low, they need " critical mass", to raise their pop. to around 25,000 at least, or even more. That way, there is more economic activity ( more consumers,generates more demand for goods and services, therefore,economy increases). 

But Anguilla is only 91 km², they're going to have a hard time trying to attract highly productive immigrants/expats, because they(the potential immigrants/expats) can feel " claustrophobic" in such a small land area. 

by building this tunnel, Anguilla and St. Maarten/Martin would complement each other by increasing the land area which they can roam with vehicles, for a total of 178 km², and that can attract potential settlers to Anguilla, not to mention the increase in real estate values.

That would also bring benefits to Anguilla in the form of creating stores and services that are lacking in St.Maarten/Martin due to lack of space, thus people from that island just hopping to Anguilla via the tunnel to get them.

I have no idea how much such a tunnel would cost, and what would be the return on investment, if it's to be built with private funds. 

keep in mind that the " Chunnel" between the UK and France was a " rail-only" tunnel, because the tunnel wouldn't be able to absorve all the fumes from vehicles, that was part of the reason why they got in bad financial shape. People having to put their cars inside train wagons is not popular, not to mention time consuming, just a hassle.


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## mkt (Feb 26, 2005)

I feel that a regular car ferry service would be the way to go.


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## islander10 (Mar 29, 2013)

mkt said:


> I feel that a regular car ferry service would be the way to go.


 a car ferry is not going to cut it, is too slow,and besides, ferries don't offer service, let's say, at 3:00 a.m. 

with a tunnel, anyone can drive their car across the islands 24/7. 

Now, with the current population, specifically Anguilla with just 13,000, this might not be viable, there might not be enough commuters to charge a toll, and get back the cost of building the tunnel.

If both islands have a total population of about 160,000 people, plus the traffic from tourists visiting the islands, that wouldn't be enough to recuperate the cost of building a 7 km underwater tunnel?


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## NordikNerd (Feb 5, 2011)

islander10 said:


> a car ferry is not going to cut it, is too slow,and besides, ferries don't offer service, let's say, at 3:00 a.m.
> 
> with a tunnel, anyone can drive their car across the islands 24/7.


We have a saying in Sweden: Malmö & Copenhagen used to be separated by the sea, now they are separated by a bridge.

That is don't expect immediate integration of 2 regions because of a bridge. A toll bridge needs a lot of revenue to be financed, that is for construction, maintennance and staff. A toll bridge with a fee of 45 EUR one way for a car must generate traffic, with high fees like that means you need it to be located in a region where it's usefull for many people who are willing to pay that price.


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## islander10 (Mar 29, 2013)

NordikNerd said:


> We have a saying in Sweden: Malmö & Copenhagen used to be separated by the sea, now they are separated by a bridge.
> 
> That is don't expect immediate integration of 2 regions because of a bridge. A toll bridge needs a lot of revenue to be financed, that is for construction, maintennance and staff. A toll bridge with a fee of 45 EUR one way for a car must generate traffic, with high fees like that means you need it to be located in a region where it's usefull for many people who are willing to pay that price.


NordikNerd,

Like I've said in other posts, it all depends on the scale of the project. An Anguilla-St. Martin tunnel would be much much smaller than a bridge such as the Oresund bridge between Malmo and Copenhagen. 

The Oresund bridge is almost 8 km in its entirety, it contains *four* vehicle lanes, not counting two more lanes for emergencies, that would be 6 lanes total! plus it has two *railway* tracks.

That wouldn't compare to the scale a hypothetical Anguilla-St.Martin underwater tunnel of 7km below a body of water 12 meters deep, and just two vehicle lanes with one emergency lane in the middle.

I'm guessing the Anguilla Channel tunnel toll would be way much cheaper than an Oresund bridge, 45 euros is an exorbitant price for a toll.

Keep in mind that Anguilla and St.Martin are small islands , is not Sweden or Denmark with massive territories, where people have more " leg room" choices to roam around with their vehicles. The " stretching their legs" (having more room to drive their cars, like 178 km2 instead of 87 or 91) could be a the main incentive in supporting this project.

Now, I haven't done any " economic viability" of such a tunnel, don't know how much it would cost to build and to maintain, and if a total population of about 160,000 people or more, plus tourists traffic would be able to pay off the costs in a 30 years time window.


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## bongo-anders (Oct 26, 2008)

If all the tiny tiny islands around the Faroe Islands can be linked by tunnels then these much larger islands also can.

The Faroe Islands consists of 18 Islands with a total population of almost 50.000 people and 80% of them are linked with tunnels.


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## mpeculea (Jan 7, 2013)

I believe that there is not a problem of technical feasibility. Both solutions (bridge and tunnel) are OK. Plus there would be some other advantages to it.
I do not know anything about the political situation on the island of St. Martin, but:
1. There is an airport n the south of the island, with a runway of 2,2 km. There is another airport in the north with a runway of 1,25 km (that' short). Neither of those runways can be extended (at least not at reasonable costs). The runway of the Anguilla Airport which is currently 1,6 km long can be extended by as much as 1 km. This means that bigger aircraft can land.
2. The flat relief of Anguilla island is more suitable for a second harbor, let's say for goods. (From what i could see on Google maps, the harbor in the south of Sint Maarten is suited more for cruise ships).
So, the investment would make sense. The question is just economical: which would be cheaper, and which would make the best profits: a bridge or a tunnel. I would go with the tunnel, because of one single fact: a tunnel would not be affected by sea storms.


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## mkt (Feb 26, 2005)

islander10 said:


> a car ferry is not going to cut it, is too slow,and besides, ferries don't offer service, let's say, at 3:00 a.m.


Since when is 15 minutes too slow? Also, some islands, mine included, have ferries in ridiculous hours. Not 3am, but definitely at 4am.


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## diablo234 (Aug 18, 2008)

Well for what it's worth South Korea is building an undersea tunnel in open waters 48 meters below sea level so I guess it would be possible. That being said though I doubt traffic levels would warrant building a tunnel between the two.


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## islander10 (Mar 29, 2013)

mkt said:


> Since when is 15 minutes too slow? Also, some islands, mine included, have ferries in ridiculous hours. Not 3am, but definitely at 4am.


 yes, 15 minutes is too slow, besides, such a frequency of 15 minutes is found only in places that would have a much more higher driving population. 

A population of 160,000 people on both islands is not going to have such a short frequency. Out of those 160,000, some 90,000 might be minors that can't legally drive, and out of the remaining adult population that is eligible to drive, some might not even own a car due to various circumstances. 

So out of 160,000 people, you might only have 70,000 that own cars and can drive.


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## islander10 (Mar 29, 2013)

> The question is just economical: which would be cheaper, and which would make the best profits: a bridge or a tunnel. I would go with the tunnel, because of one single fact: a tunnel would not be affected by sea storms.


 I think a bridge would be cheaper, but there are various problems with it, not just the sea storm factor. 

1) I would have to be very high, or be able to open up for the passage of very tall ships through the Anguilla Channel.

2) Like I've said in other posts, a bridge would be a horrible "eyesore" for the view of the channel and the islands. Many hotels/home owners would oppose the construction of such a bridge. 

These islands main industry in tourism, what they sell is " geographical beauty", unspoiled panoramic views", etc. A bridge would ruin that.

a tunnel,although more expensive,on the other hand, is " hidden from view", thus it would not have the negative externalities that a bridge would have.


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## mkt (Feb 26, 2005)

islander10 said:


> yes, 15 minutes is too slow, besides, such a frequency of 15 minutes is found only in places that would have a much more higher driving population.
> 
> A population of 160,000 people on both islands is not going to have such a short frequency. Out of those 160,000, some 90,000 might be minors that can't legally drive, and out of the remaining adult population that is eligible to drive, some might not even own a car due to various circumstances.
> 
> So out of 160,000 people, you might only have 70,000 that own cars and can drive.


And are you expecting all 70,000 to drive?

An hourly ferry is more than enough for both islands. If we can get by with less than that on an island with almost 4 million residents (over 2 million licensed drivers), then so can Anguilla/SXM.


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## Suburbanist (Dec 25, 2009)

The goal is to boost Angulla population I think.


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## NordikNerd (Feb 5, 2011)

islander10 said:


> keep in mind that the " Chunnel" between the UK and France was a " rail-only" tunnel, because the tunnel wouldn't be able to absorve all the fumes from vehicles, that was part of the reason why they got in bad financial shape. People having to put their cars inside train wagons is not popular, not to mention time consuming, just a hassle.


What about the exhaust gases in a 7km long tunnel ? I don't know about an underwater car tunnel as long as 7km. Must be health hazardous to drive in such a long tunnel even with large fans. Those fans must consume lots of electricity.

Why not build a railway tunnel ? Do you have any rail in your country?


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## mpeculea (Jan 7, 2013)

The problem of exhaust evacuation on a 7 km long tunnel is much easier to solve than a 50 km long one. And as I have seen on Google maps, there is no railway. I think there must be more than one technical solutions to this problem. Of course, all of them come at certain expense.

--
Edit (11.04.2013)

I have come today upon a post in the International thread for Turkish Motorway thread, which might be interesting to this topic. It is about the Eurasia Tunnel in Istanbul, which will be 5,4 km long, and will cross the Bosphorus Strait. 

Here is the topic: 
http://www.skyscrapercity.com/showpost.php?p=102167099&postcount=405

and more iformation about the project...
http://www.avrasyatuneli.com/en/about-project.html


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## Ocean Railroader (Jun 18, 2011)

I think a local streetcar system between these two islands would be better in that I think the cars have kind of overrun some of these small islands. In that a lot of these places are less then 30 miles across and a streetcar would be far better then more highways in that a lot of the people live in apartments.


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## Galro (Aug 9, 2010)

NordikNerd said:


> What about the exhaust gases in a 7km long tunnel ? *I don't know about an underwater car tunnel as long as 7km*. Must be health hazardous to drive in such a long tunnel even with large fans. Those fans must consume lots of electricity.
> 
> Why not build a railway tunnel ? Do you have any rail in your country?


We (as in Norway) are currently constructing a 14km underwater tunnel  and the 9 km long sub-sea Karmøy Tunnel for cars. 


We already have the Bømlafjord tunnel, the Eiksund tunnel, the Oslofjord tunnel and the North Cape tunnel which are all around 7km long.

In additonal to those, then we are planning another sub-sea tunnel called Rogfast which will become 25km long.


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## NordikNerd (Feb 5, 2011)

Galro said:


> We already have the Bømlafjord tunnel, the Eiksund tunnel, the Oslofjord tunnel and the North Cape tunnel which are all around 7km long.
> 
> In additonal to those, then we are planning another sub-sea tunnel called Rogfast which will become 25km long.


Strange how little I know about Norway. At a closer look I see what a complicated geography Norway has along its coastline.


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## diablo234 (Aug 18, 2008)

NordikNerd said:


> Why not build a railway tunnel ? Do you have any rail in your country?


Considering that St. Martin and Anguilla don't have a rail network, building a railway tunnel would be redundant.


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## mpeculea (Jan 7, 2013)

^^
Beside, there are two problems with a rail connection:
1. Anguilla has low population and low population density, which raises the question about how the people will reach the railway.
2. Saint Martin has denser population but also mountain-like relief, reaching up to 400 m., which makes building a railway quite expensive.


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## goschio (Dec 2, 2002)

Some simple causeway like in the Florida keys would be the way to go. Constructing a 7km tunnel would be just insane.


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## ChrisZwolle (May 7, 2006)

A tunnel (or bridge) would likely cost 5 - 7 times the annual GDP of Anguilla. It's like Germany building a $ 22 trillion tunnel.


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