GB2385025A

GB2385025A - Life raft deployment position indicating device

Info

Publication number: GB2385025A
Application number: GB0202946A
Authority: GB
Inventors: Mario Francesco Siano
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-02-08
Filing date: 2002-02-08
Publication date: 2003-08-13
Anticipated expiration: 2022-02-08
Also published as: GB2385025B; GB0202946D0

Abstract

A device is fitted to a stowed life raft which is operable to indicate the geographical position of, and time period since, the deployment of the life raft. The device is activated or deactivated automatically on deployment of the life raft and will continue to operate for the life of any power supply it needs to operate. The device allows those finding the life raft to limit any potential search areas more effectively and also quickly identify false alarms from accidentally deployed life rafts. The device may be fitted to new life rafts or retro-fitted to existing life rafts.

Description

DESCRIPTION DRIFT START POSITION INDICATING DEVICE (DSPID).

NB. When a waterborne craft sinks or founders, if she is carrying life rafts, they are usually designed and stowed in such a way that they will detach from the craft and deploy automatically. There may also be times when they are merely lost or washed over the side by bad weather, unnoticed by the crew, however they still deploy automatically.

NB. 2 For Life Raft also read "life boats and survival craft".

Background.

Whenever an inflated or deployed life raft or survival craft is found adrift at sea, Un-occupied by living persons and has not been reported as merely lost from a craft; Search and Rescue (SAR) Authorities are obliged to assume this could be the first indication of a foundering. This could mean that there might be people, in the water, in other life rafts, clinging to wreckage, marooned, or on or under the upturned hull of the craft from where the life raft originated Therefore SAR authorities will, immediately, calculate a search area and task SAR Units (SRUs) to search it.

In the meantime, the SAR Authority will attempt to identify the craft that the life raft was allocated to, by tracing, the life raft serial number and other means of identification the life raft may be carrying. When the identity of the craft is found they will then attempt to check on her safety, or not. This operation can take from as little as an hour or up to several days.

Until the craft has been declared safe or until all persons are accounted for or presumed dead, SRUs must continue to search the calculated search areas.

With no further information available other than a found life raft, these search areas can only be based on back tracking various drift elements, that include, divergence, leeway, tides and currents, for the distance the life raft could have drifted in the time that persons from a foundering could have survived. If survivors, are assumed to be in another life raft, or the water is warm, this could be several days. Therefore, the distance between the found position of the initial life raft and the survival time position could be very great indeed. A line is then drawn up between these two positions and an infinite number of drift start positions (DSPs) are assumed along that line. From these DSPs the various drift elements are then reapplied out to a distance dependant on elapsed time from when the life raft could have been there, and search datum time (the time the search area is at its'"best".) Various errors are then applied to these datum positions and the whole lot boxed off into a search, area or areas, dependent on the likely targets. These search areas are usually massive, having to be recalculated at regular intervals and continuously growing in size. Therefore it

could take several days for available SRUs to search, to give survivors from a foundering any chance of being found.

As can be seen, a method of modifying this massive search area is needed.

This is easily achieved if the drift start time (DST) of the initially found life raft is known- (See patent application GB 0111667.2 Marine Search and Rescue Timing device.) This will then allow SAR Authorities to calculate a search area based on a fairly standard method known as the"Backtrack". This involves back tracking various drift elements for the distance the initial life raft would have drifted in the time since deployment and being found. This usually gives three drift start positions in a fairly tight curve where it could be assumed that the foundering took place.

From these positions the appropriate drift elements'for various targets are reapplied forwards to search datum, time and positions. To these positions various error circles are applied and the whole lot boxed of into the search, area or areas, dependant on the assumed targets. This results in search areas that are many, many times smaller and infinitely more accurate than search areas based on unknown drift start times, as explained previously.

Having explained the background, I now come to the subject of this application for patent.

As explained in the background; To calculate an accurate and effective search area, relies on having an indication of drift start time to allow 5AR Authorities to calculate a drift start position to work forward from to obtain search datum positions.

However, the smallest, most accurate, and therefore most effective search areas are obtained when, the actual, drift start time and drift start position is known.

A device that is in common use at the moment is the hand held Global Positioning System (GPS) receiver, this displays the users'geographical position, updating this position as the user moves. Although one of these might be a good addition to a life raft; As can be seen, because when activated they continually update their position with movement, they would only display the actual position of the drifting raft. When what is actually needed is the position the raft deployed and therefore started to drift.

This could be achieved using a similar device to that described in the previous paragraph; Activated in some way by the deployment of the life raft and then continuing to display that deployment position, without updating as the life raft drifts, coupled with, an elapsed time from the deployment. (See patent application GB 0111667.2 Marine Search and Rescue Timing Device.) The displayed, drift start position and drift elapsed time could then be read by the finder of the initially found life raft and relayed to 5AR Authorities. SAR Authorities now have the necessary information to calculate the tightest and most accurate search area, based on the Datum Point method. This is likely to produce a search area ten times smaller than even the standard Back Track method and hundreds of times smaller than the initially described search area produced when no drift start time is known.

I re-iterate-The Drift Start Position Indicating Device is; A positioning device that may lay dormant within a stowed life raft and is activated by the deployment of the said raft, in such a way that it continues to have the ability to display to the finder, the deployment position, within reasonable accuracy, of that raft.

And/or A positioning device that may lay activated within a stowed life raft and is deactivated by the deployment of the said raft, in such a way that it continues to have the ability to display to the finder, the deployment position, within reasonable accuracy, of that raft.

And/or A positioning device within a stowed life raft that has the ability to continue to display the deployment position, within reasonable accuracy, of that raft.

To obtain optimum performance from this device it needs to work in parallel with either, an integral, or separate stopwatch that shows the elapsed time since raft deployment. (See application for patent GB 0111667.2 Marine Search and Rescue Timing Device) Possible methods of achieving the required effect could be.

Plumbing the device into the life rafts'electrical system that activates when the raft is deployed in water, and/or, by use of a pin or switch that may be physically pulled out or triggered by the action of the life raft deployment or activation.

It is intended that'The Drift Start Position Indicating Device'has the ability to display at first hand to the finder of a deployed life raft the position, within reasonable accuracy, of the deployment of that raft. Therefore, this does not relate in any way to positions and times that may be received or indicated by radio signals transmitted by Emergency Position Indicating Radio Beacons, (EPIRBs.)) and associated PLBs, ADELTs, SARBEs etc.

Apart from assisting in saving many lives ; The Drift Start Position Indicating Device, possibly coupled with the "Marine Search and Rescue Timing Device" (see GB 0111667. 2) will ; Also assist, in various enquiries and investigations related to founderings, rundowns and in the location of sunken craft..

It will also greatly decrease, the cost of Search Unit deployment and the danger to Search Unit Crews.

Claims

CLAIMS THE DRIFT START POSITION INDICATING DEVICE.

(1) A device in a stowed life raft that is activated automatically when the life raft is deployed automatically or by other means, and continues to, for the life of any power supply it needs to operate, have the ability to display, at first hand, the geographical position, date and time of deployment, within reasonable accuracy, of that raft.

(2) A device in a stowed life raft that is de-activated automatically when the life raft is deployed automatically or by other means, and continues to have the ability to display at first hand, the geographical position; date and time of, and/or indicate the time period since, deployment, within reasonable accuracy, of that raft.

(3) A device in a stowed life raft that is activated automatically when the life raft is deployed automatically or by other means, and continues to, for the life of any power supply it needs to operate, have the ability to display, at first hand, the geographical position and period since deployment, within reasonable accuracy, of that raft.