User talk:69.204.131.53

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[edit] Titanic more seaworthy than most cruise ships today!

(Moved from Talk:M/S Sea Diamond -- Petri Krohn 04:37, 15 April 2007 (UTC))

The demise of the Sea Diamond points to a startling possibility; this is that the Titanic's design if directly compared to the Sea Diamond and most other ships today may be more seaworthy. Ignoring for a moment the lifeboat deficiency on the Titanic and considering only whether a modern cruise vessel would survive a collision better than the Titanic it appears the Titanic would have a better chance of staying afloat than most modern ships! It probably would have survived the Sea Diamond accident and the Andrea Doria accident.

Modern ships are likely to be notoriously unstable compared to the Titanic. Stability is crucial to being seaworthy. Modern vessels have been built extremely high (way too high) and most have watertight compartment and deck configurations that actually lead to instability once flooding begins. Many use longitudinal bulkheads in addition to transverse bulkheads. Longitudinal bulkheads are bulkheads along the length axis of the ship that reduce flooded area but can cause instability during flooding (Andrea Doria and Lusitania are examples). Modern ships also have watertight deck arrangements on top of the compartments that are intended to prevent overflow but that raise the center of gravity of the vessel once flooding begins from above (because water is trapped high and can't get low into the compartment). Furthermore they have a shallow draft of only 25 feet or much less to get into tourist ports. On the other hand, the Titanic, Queen Mary, and others had drafts of 30 to 36 feet - these older ships were designed to endure the large North Atlantic waves and were intended for traveling just from Europe to New York and Back - so they did not need to deal with shallow ports of call.

Modern ships can give the appearance of stability through "active" control(stabilizers, ballasting tank control, etc.) but once they stop dead in the water and are subject to flooding, and without any active counter-listing controls available, the physical laws of "center of gravity" and "center of bouyancy" take over. In these situations the truly poor "passive" or sometimes called "natural" stability of most modern vessels becomes apparent. Once these ships start to list, water can pour into open portholes and the list will grow until the vessel rolls over!

In the case of a vessel like the Sea Diamond, while it is speculation at this point, we will likely find out once the enquiry is finished that the instability that occurred once flooding started resulted in a list that allowed water to flow into open passenger cabin portholes on the starboard side. This caused even greater unbalance which eventually capsized the vessel and sank it! Many of the provisions that modern marine engineers claim should help ships such as longitudinal bulkheads, side tanks and watertight decks above the water line actually facilitate the sinking because they confine flooding in locations on one side of the vessel where it tends to pull over the vessel (make it list excessively). Once this process starts even more water can pour into open ports and vents, etc. The Andrea Doria suffered the same fate as the Sea Diamond from a flooding stability perpsective. Even the US battleship West Virginia with its longitudinal bulkheads at Pearl Harbor in 1941 rolled over due to one-sided flooing after it was torpedoed. It might not have done so with transverse bulkheads only.

In the case of the Titanic, that ship was designed with a robust transverse-only bulkhead system (meaning all bulkheads are perpendicular to the length of the vessel) and the bulkheads went high enough to allow flooding of any two watertight compartments without the ship being in danger of sinking and even up to 4 four comparments in the forward section without sinking. This capability was equal to or better than the ship design standard in use today! (note: the iceberg collision in 1912 opened 5 compartments fully to the sea and one partially which is why it sank. With five full the bow sank enough that they could overflow into the next compartment and so on).

Transverse bulkheads allow flooding across the width of the ship so that the ship maintains stability, whereas with a longitudinal bulkhead flooding is on one side which causes the ship to list severely. The use of only transverse watertight subdivision on the Titanic was the reason why Titanic maintained near perfect stabililty (listed no more than 5 degrees to starboard or port) during the massive amount of flooding that led to its sinking. Many modern ships using both tansverse and logitudinal bulkheads would have likely rolled over at some point within an hour of the iceberg collision. Even those modern ships without intentional longitudal bulkheads, still can flood assymmetrically because of the space between double hulls on one side or fuel/water tanks on the sides that effectively act as assymmetrical ballast if the ship gets hit on the side (e.g. Andrea Doria).

Today, many media reports, documentaries, and Hollywood movies state that the Titanic had insufficiently high bulkheads and a lack of a watertight deck above the compartments and this made it vulnerable due to overflow issues. This is not true. In fact, these very features made the design more robust than most modern ships because it was the perfect balance of sufficient compartmentalization coupled with an approach that maintained ideal stability under extreme flooding conditions. And, as stated earlier, Titanic would pass or exceed today's standard for the number of compartments that could be flooded without loosing the ship!

More compartments, higher bulkheads and watertight decks, like we use today, don't offer any improvment if the vessel rolls over and floods through portholes due to instability. In fact, instability, can even make it impossible to get off the ship in lifeboats! Thank goodness for modern self-launching lifeboats!

After the Titanic disaster in the summer of 1912 a committee of politicians insituted "knee jerk" government regulations (based in part on recommendations from some business managers and engineers of competing shipping lines at the time) to require watertight decks above the top of the bulkheads and also in some cases more use of longitudal bulkheads and side compartments or double side walls - and of course enough lifeboats for all. At the time of the 1912 Titanic enquiry these compartmentalization recommendations may have been thought to be an improvement over Titanic's design. However, since that enquiry 90 years of experience in sea disasters has been gained. The Lusitania, the Andrea Doria, battleships at Pearl Harbor that rolled over and many other ships that have sunk since that time, sank either in part or fully due to instability resulting from assymmetrical flooding cause by longitudinal bulkheads and watertight decks. Even the Britannic, a later finished sister ship of Titanic which was modified with the changes recommended by the committee, sank after hitting a mine in WWI or being torpedoed and it was later determined that assymmetrical flooding through portholes on one side contributed to the speed of the sinking. Had the committee's recommendations not been adopted for Britannic the ship might not have sunk!

We now understand that the Titanic's method of watertight construction is superior! We have proof too since its sister ship (Olympic) survived a collision to its side with much more damage than what occurred to Andrea Doria or Sea Diamond. We have seen numerous ships with the design recommendations of the 1912 enquiry committee sink!

What gives the false appearance of safety today in cruise ship accident statistics is the fact that modern radar and navigational aids prevent most collisions from happening altogether. This fact has allowed the ship builders to drop the focus on what happens to a ship after if collides with an object and concentrate on very tall designs.

What is truly frightening today is that many modern cruise ships not only have watertight compartment designs and hull designs that are much less stable than the Titanic, but also that these ships are built very high - twice as high from the perspective of the number of decks above the waterline that the Titanic had. Furthermore, they have a depth of draft that is less! These new megaships are, in my opinion, a stability disaster waiting to happen! Just last year there was an incident where a megaship steeply listed more than 15 degrees to one side due to a rudder malfunction. To have a sharp turn event that causes so steep a list on the Titanic or Queen Mary with full-hard right or full-left rudder would be unimaginable.

One day there will be a rollover and thousands of casualties if people don't take this issue more seriously. Having enough lifeboats does not do any good if you can't get to them when the ship is rolling over! I guess we have a name for this; its called "The Posieden Adventure!"

The shipping industry needs to re-evaluate its designs and start taking natural stability into account. In the meantime, I'll feel uneasy on any modern cruise ship. —Preceding unsigned comment added by 69.204.131.53 (talk • contribs) 20:31, 14 April 2007

This could be developed into an article on Ship stability‎. I started a one line stub. -- Petri Krohn 06:26, 15 April 2007 (UTC)