There are a number of systems out there designed to keep pirates from boarding ships, incorporating everything from lasers to acoustic devices to writhing water hoses. However, what happens if the pirates get on board anyway? If the ship is equipped with the Marine Armor System, a series of ballistic blinds will roll down throughout the vessel, blocking access to its interior.
The blinds sit rolled up in receptacles when not needed, located above the ship's various doorways, hatches and windows. When a pirate-boarding is imminent, however, the press of a single centrally-located button will cause them to all roll down within 10 seconds.
The pry-resistant blinds are made from a proprietary alloy known as Kriptonia, which is claimed to be stronger than steel. Depending on what they're being used to secure, different levels of ballistic protection can be selected.
The Kriptonia Basic blinds, for instance, have a ballistic classification of FB1. This means that they can withstand shots from a .22-caliber handgun, so they would be useful as an economic means of protecting cargo or machinery, but not crew members. At the other end of the spectrum, though, the Kriptonia 100 blinds are rated at FB6, meaning that they block shots from heavy military weapons – these are what would be used to keep the crew safe.
For dealing with things like rocket-propelled grenades and thermal lances, there are versions that combine the Kriptonia 100 blinds with a high-strength steel mesh, or that incorporate two layers of blinds.
Along with its use on cargo vessels and tankers, the Marine Armor System is also aimed at offshore platforms such as oil rigs. A version for luxury yachts is additionally in the works.
You can see the blinds in use, in the video below.
Source: Marine Armor System
It has been known from the time of the Assyrians that passive fortifications alone, no matter how heavy, are useless unless combined with active means of defense. The latest well-known case where that mistake was made was the infamous Ferdinand/Elefant superheavy tank of WWII, which had no machine guns, meaning that it could not engage infantry. Scores of these behemoths were destroyed by Russian infantry who swarmed over them, ripped their treads off with grenades, and poured burning gasoline down air intakes.
It appears that the makers of these blinds still haven't learned that fact after 4000 years worth of lessons. Or maybe they have, but cynically just want to make a buck peddling an illusion of invulnerability.
The only way these blinds could actually work is by combining them with _well placed_ firing ports, covering all avenues of approach. And they better cover _all_ of them; another case in point is the ignominious fall of the WWII superfortress Eben-Emael, which you can google for yourself. Again, this is nothing new; every effective castle or bunker ever built has followed this principle.
And for the Somali pirates out there, the best way of defeating these blinds is to get under the sealed-off bridge compartment, and light a big petrol fire there. The besieged will fall over themselves in their haste to throw the armored blinds wide open. This tactic has been used effectively against immobilized tanks.
http://en.wikipedia.org/wiki/Elefant#Combat_history http://en.wikipedia.org/wiki/Battle_of_Fort_Eben-Emael
(disclaimer for the inevitable hard-of-thinking: I am not really trying to help out Somali pirates. I am writing about this tactic in the same spirit as people who openly publish software exploits---in order to get the makers thinking about countermeasures.)