Triple-E Ship Leaves Port With World Record Load • Hacker News Board

Re: Triple-E Ship Leaves Port With World Record Load

#61

Post by dredmorbius » Wed, Aug 20, 2014, 10:41 PM UTC

dredmorbius wrote: post #42

D_Alex wrote: post #24

21 years ago I was in a Korean shipyard where the largest container ships of the day were being built. Their capacity was 6000 TEUs, one-third of the Mary Maersk. The captain of one of the ships (a 27 year old (!) German woman) told me most ports cannot handle the 6000 TEU vessels, so their line will be building mainly 4500 TEU ships. One interesting thing is that those older, smaller ships had more powerful engines…

Fuel costs have increased hugely since. The present generation of ships are designed for "slow steaming", ~13 kt, at a very significant fuel savings. That's likely to extend for much of the life of the ships (~20 years, possibly more).

NB: ~19 kt, not 13, as discussed in the Triple-E Wikipedia article elsewhere in this thread, for 37% fuel savings.

Re: Triple-E Ship Leaves Port With World Record Load

#62

Post by jacquesm » Thu, Aug 21, 2014, 7:00 AM UTC

toomuchtodo wrote: post #60

jacquesm wrote: post #46

Earlier quoted context omitted.

When you strike a container at speed all bets are off, regardless of what material your boat is made of. You're in a catamaran, at least you have two hulls rather than just one. And it would appear that the part that is underwater is the most important bit when it comes to striking containers so I'm not sure why you think a titanium superstructure will help you if there is a gaping hole in your hull.

A titanium hull failure is superior to a fiberglass or wood hull failure. Even if I hit a container at speed, the worst scenario is the structure deforming, versus fiberglass failure scenarios.

A titanium hull is, but you mentioned superstructure, which is everything above the hull.

Re: Triple-E Ship Leaves Port With World Record Load

#63

Post by jacquesm » Thu, Aug 21, 2014, 7:13 AM UTC

toomuchtodo wrote: post #59

jacquesm wrote: post #58

Earlier quoted context omitted.

Maybe he expects to be hit from above by the container?

No, I expect to hit roughly head on. A container won't show up on radar, and its hard to detect something that near the surface using any sort of transducer/depth measurement device. Titanium is non-reactive/corrosive, lightweight, and extremely durable. I'm extremely confident of the design, ensuring survivability of a container encounter, even at 12-15 knots.

Titanium is expensive. So people that build hulls (not the superstructure, let's take that as a given) out of titanium tend to make those hulls fairly thin. Containers are made out of thick chunks of angle and square profile welded together, with huge sheets of steel in a double wall in order to make the structure rigid. So rigid that you can stack them 10 to 15 high loaded without any of them buckling.

If you ram something like that (at it's own velocity, which will be roughly the speed of the current) at a vessel made out of titanium (thin, because it is expensive) then you're essentially aiming a can opener at a can.

I'm really happy that you're extremely confident of the design but I really hope you're going to do the normal thing and run with the regular complement of safety gear on board for the crew (raft, vests etc) because I fear that you may be over-estimating the degree to which oceanside encounters with container sized semi submerged obstacles weighing multiple tons allow themselves to be predicted.

FTR my somewhat checkered career included working for a sail making company and I've seen a few boats that had very mild collisions at sea and on the larger lakes and those definitely did not look pretty. I've never seen a boat come back that had had a head-on encounter with something the size of a container.

Titanium is a great material, but it is (very) hard to work, if used properly can give you the same strength as steel for a lighter weight. But due to the higher material costs and higher costs to work it you will more than likely end up with a boat that is just as expensive as a steel one with slightly less displacement or you'll end up with a boat that is much more expensive than a steel one.

In the end whether or not you will survive a container encounter depends to a very large degree on what the relative velocities are and how the container is oriented relative to your boat. If the container is dead in the water and you hit it at a 45 degree angle no amount of metallurgy will stop you from having a breached hull unless you go for something that will also survive impact with an iceberg.

Which reminds me of some other captain that was convinced his boat could handle anything the ocean could throw at him.

Be safe.

Re: Triple-E Ship Leaves Port With World Record Load

#64

Post by jacquesm » Thu, Aug 21, 2014, 9:44 AM UTC

toomuchtodo wrote: post #59

jacquesm wrote: post #58

Earlier quoted context omitted.

Maybe he expects to be hit from above by the container?

No, I expect to hit roughly head on. A container won't show up on radar, and its hard to detect something that near the surface using any sort of transducer/depth measurement device. Titanium is non-reactive/corrosive, lightweight, and extremely durable. I'm extremely confident of the design, ensuring survivability of a container encounter, even at 12-15 knots.

Afterthought: and remember to look very closely at the corrosion of other materials the Titanium connects to, you can't just mix two kinds of metal in one construction exposed to salt water without figuring in exactly where the contact points are between the two kinds of metal and how you deal with the potential difference at that point. The typical way is to use some kind of sacrificial anode at the stern of the vessel (and possible a few others if it is large enough), if you don't take care of this you may lose fittings, stays and terminals well before their time.

Re: Triple-E Ship Leaves Port With World Record Load

#65

Post by toomuchtodo » Thu, Aug 21, 2014, 6:21 PM UTC

jacquesm wrote: post #63

toomuchtodo wrote: post #59

Earlier quoted context omitted.

No, I expect to hit roughly head on. A container won't show up on radar, and its hard to detect something that near the surface using any sort of transducer/depth measurement device. Titanium is non-reactive/corrosive, lightweight, and extremely durable. I'm extremely confident of the design, ensuring survivability of a container encounter, even at 12-15 knots.

Titanium is expensive. So people that build hulls (not the superstructure, let's take that as a given) out of titanium tend to make those hulls fairly thin. Containers are made out of thick chunks of angle and square profile welded together, with huge sheets of steel in a double wall in order to make the structure rigid. So rigid that you can stack them 10 to 15 high loaded without any of them buckling. If you ram so…

> I'm really happy that you're extremely confident of the design but I really hope you're going to do the normal thing and run with the regular complement of safety gear on board for the crew (raft, vests etc) because I fear that you may be over-estimating the degree to which oceanside encounters with container sized semi submerged obstacles weighing multiple tons allow themselves to be predicted.

Of course. To do otherwise would be insanity.

> Be safe.

Thank you.