

Is It Possible to Build an "Unsinkable" Ship? - robdoherty2
http://www.scientificamerican.com/article.cfm?id=unsinkable-titanic-engineering

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mixmax
Of course you can build an unsinkable ship, as a matter of fact for some uses
it's mandated by law.

If you build in fibreglass you will usually make a sandwich construction with
fibreglass on either side and a layer of stiff foam in the middle. This
construction technique is widely used because you can make strong and light
boats with it. If you place enough foam in the lower part of the boat (enough
to displace the weight of the ship) you have an unsinkable ship. Even if it
breaks apart the pieces will still float.

I've seen small boats of this design in the harbour where I live that have
been left unattended for years, and they don't sink, even when they're full of
water.

The question is whether you can build a _large_ and _commercially viable_ ship
that's unsinkable. For larger vessels it's usually not an option to have the
lower decks filled with foam, since it detracts substantially from the cargo
or passenger carrying ability.

~~~
bmelton
I clicked to post exactly this. I live on the Chesapeake Bay, and it seems
like half the boats in the local Craigslist are of the unsinkable variety.

I think what the article is really getting at is whether or not it's possible
to build an indestructible ship, and of course, the answer to that is no.

It's possible to make a ship that is much stronger than the people it carries
-- most ships are, but that doesn't make the people any less fragile or more
susceptible to death, injury or drowning.

Submarines are perhaps a superior design for this, on paper, but generally
speaking, a submarine isn't where you want to be if the submarine is in any
danger whatsoever.

So yeah, unsinkable boat? Check. Unsinkable passengers? No check.

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tedunangst
Unsinkable passengers? Sure. Just make everybody wear drysuits and floaties.
It may not be Titanic chic, but you can't have everything.

~~~
ben0x539
If you get caught under deck while the unsinkable ship is flooding with water
and possibly going belly-up, that might not help you much.

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Groxx
I don't see why it would be impossible to make an unsinkable ship. Just make
it out of material that's less dense than water.

~~~
delinka
Less dense than water and strong enough to withstand choppy seas, storms,
pirates, accidents ...

It might not sink, but if it won't hold together, you can't keep people and
stuff inside it. Of course, I'm not a materials expert, but this seems like a
good reason our ships are made of metal.

~~~
rorrr
There are many materials that are stronger than steel and lighter than water.

It's all about costs, not about technology.

~~~
ars
Such as?

And stronger by weight or by volume? Stronger in tensile strength or by
compression? In resisting flexing? Can it handle vibration and bending without
cracking? Is it tough enough not to be abraded? Can it distribute stress (by
giving a bit)?

The word "stronger" by itself has no meaning in engineering. You need to
specify all those things I listed when describing stronger.

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cpleppert
I have a minor quibble with this article. We have a pretty good reason why
they didn't either extend the watertight compartments or use a double hull in
the construction.

Extending the watertight compartments up into the ship makes passenger
movement much harder; a killer for a ship built around luxury.

The double hull would have added a lot of weight to the ship. Titanic's sister
ship Britannic required a bigger engine to maintain the same speed and was
less economical as a result. Titanic was expected to perform weekly Atlantic
crossing over a very long lifetime and the cost would have been substantial.

~~~
hef19898
Baseline for me is, the Titanic was built in 1912 to the standards they had
back then (afaik even the insufficient number of live boats was accepted
then), SOLAS was aresult of that disaster.

Imagine the Costa Concordia would have been lost not at shore but at high sea,
the same result.

What happened in both cases, or is currently happening, is a review design and
operating guidelines, which is good. And double-hules are still not common
place, even today.

And yes, after all it has been, is and will most likely be for quite a long
time about the trade off between safety and profitability.

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orangewarp
These guys tout an unsinkable sailboat. Boat inside a boat with foam in
between. Apparently you can punch a big hole in it, flood the inner
compartment and it will still be able to sail. I suppose if you snap off the
keel then it could go upside down, which isn't very good to you even if it
floated. So really "unsinkable" means more than the ability to float.

<http://www.etapyachting.com/>

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patrickgzill
Isn't a better question: Is it possible to build a ship that ensures passenger
survival even if the boat is partially destroyed?

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ben0x539
My best idea is to build your ship out of a dozen smaller ships and then tie
them together.

~~~
ars
Be careful they don't drag each other down if a number of them sink.

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bcardarella
<http://en.wikipedia.org/wiki/Boston_Whaler#Unsinkability>

~~~
gk1
Boat != Ship

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davorb
The Titanic wasn't the largest ship ever built. It had a sister ship that was
built earlier and of the same size. About two weeks after Titanic was built,
an even larger ship was constructed.

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Tzunamitom
Wouldn't it be cheaper to focus on emergency failsafe devices or similar
safety solutions to those incorporated by modern aircraft?

Examples include:

-Self-righting mechanisms

-Self-sealing compartmental design

-Re-floating devices

-"Carefree" fly-by-wire preventing dangerous manoeuvering

~~~
gk1
All of these already exist in some form:

> Self-righting mechanisms

Modern ships can easily transfer ballast fluids (typically sea water, but
sometimes fuel or distilate water) to correct any listing. There are no
methods of righting an overturned ship because that would require an
astronomical amount of moment.

> Self-sealing compartmental design

Watertight doors can be controlled from multiple stations on the ship, such as
the bridge or the engineering control room.

> Re-floating devices

If you mean safety devices: Ships carry liferafts that, in the event of
sinking, automatically detach from the ship, float to the surface, and
inflate. If you mean re-floating the entire ship: Not feasible to re-float
something that weighs hundreds of thousands of tons just to save some scrap
steel.

> "Carefree" fly-by-wire preventing dangerous manoeuvering

Ships have automatic navigation and piloting, though not in shallower waters
such as in ports.

~~~
Tzunamitom
I'm not reinventing the wheel here, or suggesting anything new - just that
focusing on _improving_ these would be a better investment of resources than
creating an unsinkable ship.

For example:

* How good are the systems that realise that ships need righting and transfer the ballast automatically before it overturns?

* Refloating may not be feasible once the ship is overturned, but by then it'll be too late. How about self-inflating bags that inflate as the ship _starts_ to sink, buying valuable time for people to escape?

* Automatic navigation is one thing, but how can we improve it? Does it identify foreign objects above/below the waterline? Does it have stabilisation assistance? Does it pump ballast around to ensure the best possible handling under any condition?

Just because these things already exist doesn't mean they can't be improved.
In some cases this could potentially be done relatively cheaply.

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fleitz
Sure it's possible, but is it economical?

Every person is only willing to pay so much for a ticket, you could make ships
that couldn't be sunk but it would cost so much that it wouldn't be worth it.

Instead of making unsinkable ships, we put lifeboats on sinkable ships.

~~~
excuse-me
Exactly - these are pretty unsinkable, but not very comfortable for a cruise -
<https://en.wikipedia.org/wiki/Tamar_class_lifeboat>

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politician
tldr: "The short answer is no."

~~~
dredmorbius
<http://en.wikipedia.org/wiki/Betteridge%27s_Law_of_Headlines>

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loverobots
Maybe, but probably not a ship that carries 1000 passengers, 1 million barrels
of oil, fish, bring iPads from China or whatever ships are generally built
for. So the answer for the real world is probably not.

