1. Reaching the Sea Floor

The watery fate on 15th April 1912 of the "Titanic", at the time the world's largest ocean liner, affected many communities, particularly on both sides of the Atlantic. For example, we can note the story of heroism of one Father Byles from Ongar, in Essex, near London.

Over a century later, the disaster, on 18th June 2023, of the "Titan" submersible, which took tourists on a deep sea dive to view the remains of the "Titanic", has, of course, first and foremost, been a tragedy for the families of the five people who lost their lives.

The ensuing inquiry has had the aim to start the process of giving some closure to the bereaved families, and to try to prevent a future accident of the type suffered by the passengers of the "Titan". See also description on this page. Inquiry topics covered, included: (1) design and safety. (2) accountabilty, and (3) insurance.

The current web page you are now viewing, whilst in no way constituting a legal or expert statement, gives my humble understanding of the enormity of the physical water pressures that occur at the bottom of our oceans and specifically, here, at the depth of the wreck of the original "Titanic".

2. Pressure Estimate : Our Units of Measurement

We shall use metric units for our main calculation for deriving an estimate of the pressure to which a submersible is subjected when visiting the wreck of the Titanic. Using metric units makes sense, since the official international definition in 1959 defined the weights and measures used in the English-speaking world in terms of the metric systerm of units. Thus,

• Length: 1 yard is exactly 0.9144 metre.
  This is equivalent to "1 inch is exactly 2.5400 centimeters".


• Mass: 1 pound (avoirdupois) is exactly 0.453 592 37 kilogram

3. Pressure Estimate : Our Givens

Here we can start with two givens. One is a physical property and the other is ultimately made by the formation of our planet. Both, of course, are important for our investigation!

1. Density of Water. We assume 1000 Kg/cubic metre, although, at 4°C water has a maximum density of 997 Kg/cubic metre. See, for example: "Engineering Toolbox". A density of 1000 Kg/cubic metre means that a cube of side one metre would, theoretically, hold one metric tonne of water! Heavy!


2. Depth of Titanic. We assume 3777 metres (i.e. about 3.8 Km or almost 2.35 miles). See, for example: "Newly released Titan footage". This footage was viewed on BBC News on 19th September 2024; the video it contained was dated 22nd July 2023 and contained a depth marker counting up to 3777 metres below sea level.

There is a further "Given" which we shall mention for completeness, and then conveniently "forget"!

• "Incompressibility of Water". At this point we can actually sneak in another "Given", hopefully without adding undue complexity to the situation. Essentially, we can conveniently regard water as incompressible. This is borne out by the following source: phys.libretexts.org (sections 2.73 and 2.75 as well as Table 2.71 comparing normal and seawater). Also relevant is water-science-school.
  
  Both sources suggest that, by (1) regarding water as incompressible and (2) neglecting the distinction in mass between normal and sea water, we are likely to underestimate our mass of water, in the context of the Titan disaster, by no more than 2%! Thus, the mass (i.e. density) of water would be 2% more than our calculation on this web page would actually produce. Put another way, the conceptual column of water above the wreck of the Titanic would be 2% heavier (see relationship between mass and force in section 5 below) than the quest for simplicity of our calculation makes us assume. I think you, the reader, will agree that, in the context of the aim of this, our web page, the resulting simplicity in our calculations is a worthy aim!

4. Mass of Conceptual Vertical Column of Water

The key task is to find the mass of a conceptual column of water above the sea bed. To start with, the simple diagram shown below may be helpful.

Depth. The Titanic lies at a depth D = 3777 m [3.2 above]. Area of Square Cross Section of Vertival Column is A = 1 m2 Volume of a vertical column is V = AD = 3777 m3 Density: We assume [3.1 above] water has a density ρ = 1000 Kg/m3. Mass of this vertical column is ρV = (1000 Kg/m3)(3777 m3) = 3777000 Kg.

Conclusion So Far: The Mass of this vertical column is 3777 Metric Tonnes sitting on an area of 1 square metre on the sea floor. This gives about 3717 UK Tons (Long Tons), since 1 Metric Tonne is equivalent to 0.984207 UK Tons (Long Tons).

5. Relating Mass and Weight

According to our present knowledge of Physics, the Four Fundamental Forces in the universe comprise: Gravity, the weak force, electromagnetism, and the strong force.

The force of Gravity allows us to determine the mass of an object. Traditional weighing scales balance the unknown weight of an object on one plate against the known weights of one or more objects on the other plate.

Back to our main subject! The pressure at the base of the column exerted by the mass of the column of water is the weight of the mass of 3777 Metric Tonnes acting on an area of 1 m². This is the answer we want!

Here we can make the following observations.

• Weight of Water Column. We can reference the weight of our column of water to conditions at sea level, which, for the purpose of the calculation on this web page, we can approximate to the surface of an idealized spherical representation of the earth. This is so, because the depth D of the sea bed is negligible compared to the average radius of 6,371 km of the almost spherical earth.


• Water Pressure. The water pressure on the sea floor is relative to the normally zero water pressure at sea level.


• Air Pressure. The Air Pressure at sea level is important for us as living entities; however, it should be emphasized that this is a separate issue from the normally zero water pressure at sea level and the calculation of the water pressure on the sea floor.

We have now spoken not only about the mass of our column of water, but, also, about its weight on one square metre of the sea bed.

6. Pressure : Weight per Area

We shall show in this section that we are dealing with a very large weight which is sitting on a very small area. We shall then proceeed to put figures to this statement.

We have used standard metric units to get us this far on our journey to understand the pressure on the sea bed. However, something which is perhaps much closer to our physical being and existence, is the length of the each of the two segments of an adult's thumb. Usually, this length is about one inch for each segment. So, knowing this, let's calculate the pressure per square inch on the sea floor where the wreck of Titanic lies. Remember, from above, 1 inch is exactly 2.5400 centimeters. This means that, for our calculations on this web page, we are effectively staying with metric units! All consistent!

There are 1550.003 square inches per square metre. If the pressure on the sea floor is 3777 Metric Tonnes Force per Square Metre (as per section 4 above, bullet 4), then, per Square Inch, this becomes (3777/1550) Metric Tonnes Force per Square Inch, or about:

2.4 Metric Tonnes Force per Square Inch.

According to "My Car Import", mid-size cars in the UK, including sedans and hatchbacks, can weigh between 1,200 kg to 1,600 kg (weight or force). So, our 2.4 Metric Tonnes Force per square inch would be equivalent to balancing two of the lightest cars in this category on one square inch at sea level, if this were logistically possible!! Gadzooks!!

7. Titan Disaster : Inquiry Findings

The inquiry into the Titan disaster has ended. Here are what appear to be three relevant articles. Aspects which have been highlighted are: design of submersible, apparent over confidence in its safety, and issues such as greed and recklessness. Hence, we can probably expect further actions and consequences beyond the immediate remit of the inquiry.

1. "Key Takeaways from the Inquiry",
   (BBC, 20 September 2024),
   highlighted that the "Titan submersible was not classified or registered". The FORMER (pre-implosion disaster) operations director of OceanGate® (Titan's operating company), WARNED that the carbon fibre mixed with resin, of which Titan's hull was largely constructed, would degrade further (delamination) with every dive. Titan, before entering revenue earning service, had NOT been subject to "an extensive safety assessment carried out by independent marine organisations". The former operations director did NOT express technical confidence with Titan's construction, and left OceanGate® well before the disaster actually occurred.


2. "An 'abomination' of a sub - and the boss convinced Titan was safe",
   (BBC, 28 September 2024 @18:17).
   stated that (1) the hull's shape was cylindrical rather than spherical which implied uneven pressure distribution and (2) the window was only considered safe down to 1,300m.


3. "Allegations of Greed and Recklessness",
   (South Carolina Public Radio, Victoria Hansen, 30 September, 2024 @5:07 PM EDT).
   Victoria Hansen spoke about (1)"Allegations of greed and recklessness in the Titan submersible hearings", and (2) that there were more than 100 problems with the submersible since 2019, including a cracked hull, a thruster that failed during a deep dive and a dome that fell off.

8. Aftermath : Latest to End of May 2025

Here are pointers to the next stages, which are beyond the remit of the initial inquiry as described above. The first of these is by CenLANow® (USA), and the second by the BBC® (UK). TwinTeirs® (USA) gives an interesting description of what survived the implosion.

1. "What's next now that the hearings into the Titan implosion are over?".
   CenLANow, Jameson Moyer, 01 October 2024 @10:08 AM (Central Daylight Time, USA).


2. "Ship footage captures sound of Titan sub imploding".
   BBC, Rebecca Morelle, Science Editor, @BBCMorelle & Alison Francis, Senior Science Journalist, 22 May 2025.
   In the BBC article we learn that the descent started at about 09:19 Newfoundland Daylight Time (NDT), and almost 1½ hours later, at 10:47, at a depth of 3,346m, communication was lost. The sound of the Titan imploding was captured in the video footage being created on the support vessel on the surface.


3. "National News: Titan submersible: Items that survived the implosion".
   TwinTeirs®, Sierra Campbell, Posted and Updated: May 29, 2025 @09:39 PM EDT.

9. Attributions & Thanks

The calculations for the Pressure in units of Metric Tonnes Force per Square Inch are mine, but the sources for the necessary input data are given in the links. Of these, the following were particularly useful and relevant.

1. "Engineering Toolbox"
2. "BBC - Key Takeaways from Inquiry."
3. phys.libretexts.org
4. water-science-school
5. "My Car Import"

Many Thanks also to all the additional organisations, to which I have made links on this page!

Of course, Many Thanks to you the reader for whom this page was written!

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