The latest EPIRBs store GPS positions in their memory for a period of time. These data are fed into it at regular intervals while the ship is in normal operation. If the EPIRB is recovered these data can be forensically read, even if the battery has been exhausted.
If inspections, tests and battery changes are adhered to and the HPR changed as required, the EPIRB should float free and auto activate any start sending the last position when the ship sinks. It should continue to do so for 48 hrs. (Latest models)
The locator beacon on the latest VDRs have a lifetime of 90 days, but if the VDR on this vessel didn’t have a free float component, the unit was probably not of the latest type.
It is a pity that the regulators do not manage to change the rules as fast as the technology change.
Regulators everywhere issue [U]minimum [/U]rules. There is no law saying that an Owner/Operator cannot equip his vessel with the latest and the best on the market.
Some do, but they are few and far between.
[QUOTE=Bayrunner;171856]I wonder what the Apache is going to do when they get there with the ROV? 4 point anchor in 15,000 ft of water? It doesn’t have DP.[/QUOTE]
Where does this figure of 15,000 ft. come from. Since the position where she sunk is not known, how can anybody know??
As far as I know the depths off Bahamas on that side is variable, but you will have to be close to Samana Cay, off Crooked Island, before you get that shallow. Further away the depth >2700 fathoms (16,200 ft.) pretty quickly.
There are plenty of Offshore vessel with ROVs able to go to 3,000 m. (10,000 ft.) and a few to 4,500 m. (15,000 ft.) but beyond that they become few and far between. There are some scientific ROVs that can go to 6,000 m. (20,000 ft.) but most without powerful manipulator arms. Some manned Subs can do even better.
Sorry to be a pessimist here but even if somebody is prepared to spend the money, getting at the VDR is not going to be an easy task.
Besides the water depth, there is also the possibility that she is sitting upside down on the bottom, or that access is otherwise blocked.
There are plenty of Offshore vessel with ROVs able to go to 3,000 m. (10,000 ft.) and a few to 4,500 m. (15,000 ft.) but beyond that they become few and far between. There are some scientific ROVs that can go to 6,000 m. (20,000 ft.) but most without powerful manipulator arms. Some manned Subs can do even better.
Sorry to be a pessimist here but even if somebody is prepared to spend the money, getting at the VDR is not going to be an easy task.
Besides the water depth, there is also the possibility that she is sitting upside down on the bottom, or that access is otherwise blocked.[/QUOTE]
There are several ROV’s that can work in 6000 meters of water, Phoenix International has two, the “Remora” and X bot. Woods Hole has one or two plus some AUV’s that are capable of working in those depths. Phoenix is who operates the U.S. Navy’s sub salvage unit. There are others as well.
Most work class ROV’s are set up for oil filed support. Since 3000 meters is about the limits of drilling right now, that is why most are only capable of working in 3000 meters of water. Most of the work class ROV’s are capable of going to 4000 meters, with a pressure compensator change, changing the foam and a few other things. The big problem is the umbilical. Work class ROV’s might have been delivered with 4000 meters of umbilical, but after several end terminations and repairs they will only have enough to maintain the working depth of oil field support. Very few salvage jobs in those depths, and the oil field has no need for it, so would be real surprised if there are many 4000 meter or longer umbilical’s sitting around without having to special order, and wait a couple years.
Phoenix has a couple of towed search units capable of working in 6000 meters, that can find a lost flap from an airplane in those depths, so an entire ship should be a cake walk for those guys.
I think that they have a good idea where the ship is already. They will probably find it, obtain sonar images, and perhaps photos, fairly quickly. If the ship is lying in a position with the VDR accessible, they will eventually recover it, but that may take awhile.
What is the terminal velocity of a sinking ship? What is the effect of the hydrodynamic forces on a sinking ship?
If a ship sinks in water three miles deep, what would be its expected transfer and advance? How far might the ship sail underwater? Three miles?
Logically, just as an arrow dropped off a cliff does not fly sideways through the air, as a ship accelerates toward the bottom in deep water wouldn’t it tend to sink more or less either bow first or stern first as it picks up speed toward the bottom and sail some distance from its surface position?
Is there a 25 percent chance that the ship will lie either right side up or upside down, and a 50 percent chance that it will be lying on its side? In what position are ships that are found in deep water usually lying?
My uninformed gut instinct suggests that an ice strengthened ship that rolled over due to compromised stability in a storm probably would not break up on the way down. We probably won’t find major parts of the ship scattered over a wide area. And how much the ship would break up on impact would depend upon its speed, the angle of impact, and the type of bottom.
Do VDRs usually survive impact in deep water?[/QUOTE]
That is a good question, for which I can NOT find an answer, either from manufacturer’s specs or in IMO regulations.
Anybody else have any idea what the guaranteed or required WD capability is???
Like to clarify a few things floating in this thread.
El Faro was equipped with a S-VDR (Simplified VDR), required on cargo ships constructed before 1 july 2002. With S-VDRs one had the choice of a fixed or floatfree recording device, not both. El Faro was equipped with a fixed recording device and the minimum required items to be recorded are:
Date and Time
Ship’s position
Speed through the water or over ground with indication what it is derived from
Heading
Bridge audio
VHF communications
Radar data
AIS data, if it is impossible to obtain radar data
Additional data items listed in IMO Resolution A861(20) for VDR if data is available in IEC 61162 format.
The type fitted was a Sperry VoyageMaster II S-VDR.
Question: When was the last APT (Annual Performance Test) carried out and were there any deficiencies?
This has been brought up a couple of times, yes, there is a new requirement for VDR’s installed on or after 1 july 2014 (applicable to ships to be fitted with VDR, not for those fitted with S-VDR) that requires extended recording times (48 hrs) and both fixed and float free recording devices.
Most float free EPIRBs on existing ships don’t have the GPS feature, simply because they are less costly and meet the requirements.
Have the following questions:
which brand and type float free EPIRB was installed on this ill fated vessel, 2) when was the EPIRB last inspected and 3) which where the expiry dates of battery and hydro static release?
I guess those questions will be answered in due time by the NTSB.
As far as the search is concerned am sure that they will be checking for traces of oil appearing on the surface in the area where she disappeared. Then there is some very sophisticated equipment available such as multibeam deepwater echosounders which survey a vast area in great detail in one pass, check this one out from Kongsberg:
One of those systems is fitted on USCG icebreaker Healy, which should have finished it’s North pole expedition by now.
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[QUOTE=ombugge;171890]That is a good question, for which I can NOT find an answer, either from manufacturer’s specs or in IMO regulations.
Anybody else have any idea what the guaranteed or required WD capability is???[/QUOTE]
They are designed to withstand the pressure at 6000 meters.