PEOPLE LOST AT SEA General Idea/Discussion (Non-CNC)

[thkoutsidthebox]

Hi all,

Point.1) Recently a rock climber was swept out to sea off the Irish coast. He was a strong swimmer and very fit and healthy, he likely lasted at least 12hrs, possibly more before being overcome by hypothermia/tiredness. A friend told him that he would go for help because he couldn't climb back up the slippery rocks after a wave knocked him into the ocean. Anyway, when the friend returned and the emergency services arrived he was gone, swept out to sea, like many others each year, by the currents, and he couldn't be found. http://www.independent.ie/national-n...e-1037827.html

Point.2) I recently read in a magazine (Trying to find the article but haven't located it yet) about a university professor in the states who I believe was an oceanographer. In this instance he was specifically studying rip-tides on beaches and seem's to have debunked the conventional wisdom regarding swimming parallel to the shore if caught in a rip-tide. Anyway...his study was not possible until recently because he now adapted cheap, off the shelf, GPS receivers, to transmit their location. Previously the technology was too expensive.

So:

Something crossed my mind. Using the same system that the professor did, you could adapt cheap GPS receivers, set them to sea, and track their positions. If you released them every 100m or even every 500m along a coastline, you could create a map of the currents around the entire coast, or in the coastal areas where most people are lost each year.

You could release each bundle for perhaps 72 hours and track their positions every 15 minutes, then retrieve them by boat and move on up the coast for the next release a few days later. If you did this at high and low tide in each of the four seasons, you could build up a map of the currents. Then when a person is swept out to sea from a specific location, the emergency services could say for example:

"Grid Reference = XYZYXXZY, Season = Summer, Tide = High" (Take out relevant map)
"Person went into the water 8 hours ago"
Then by looking at the relevant map, the person should be in the general area that the GPS transmitter buoy would have been during the study after floating for 8 hours. Obviously not exact, but if a person was gone for 40 hours, it would narrow down the search area a phenomenal amount.

So some thoughts to start the discussion:

You electronics guru's...how difficult is it to adapt a GPS receiver to transmit, and how would you receive the transmissions.

Does anyone know much about ocean tides, apart from the general knowledge about the phases of the moon affecting them etc

Are ocean currents very accurately mapped in this way anywhere in the world as yet, I dont think so.

If my calculations are correct:
Ireland has 5631km of coastline (Approx).
To map the entire coastline currents every 100m for 72 hours from each start point, would take 56,310 release points.
Releasing at 10 points every three days, would take 16,893 days to do the entire coastline.
If 100 people worked in teams of two, each releasing at 10 points per 3 days and retrieving the buoys, then the entire Irish coast could be mapped in 337 days.


This is not a project I personally intend to undertake, just something I thought up and figured I'd throw out there. In the Irish example, if each person earned €30,000 for their 337 days work, then the cost would be €3,000,000, plus the cost of two powered rib boats and the diy type gps systems, I figure the entire project could be done for under €4,000,000.

Possibly a good project candidate for a Government grant if someone is interested.

To map each 100m point for the four seasons and in high and low tide, would multiply the cost by a factor of 8.

So what d'ya all think?

[Geof]

Originally Posted by thkoutsidthebox Then when a person is swept out to sea from a specific location, the emergency services could say for example:...... ....Are ocean currents very accurately mapped in this way anywhere in the world as yet, I dont think so...... So what d'ya all think?

You want the hard hearted answer? Hell of a lot of money to spend to (possibly) save someone who should have looked out for himself.

Softer answer: It could work but you would have to do all your mapping at different seasons. I grew up on the west coast of New Zealand near Auckland and was a surfer. The beach configuration and the typical 'rip currents' both magnitude and direction, varied widely in different seasons.

I read the article you refer to about common wisdom for rips being wrong and thought that guy had obviously never done any surf swimming; I knew that almost fifty years ago. We used to dive off a headland that was about 1-1/2miles out from the beach and let the rips carry us out through the surf along the beach and then back within reach of bottom; probably a 2 to 4 hour drift. If you tried to fight the direction the rip was taking you it was impossible but if you stayed afloat eventually you got back to shore. Mind you the water temperature was much warmer and hypothermia no worry.

Regarding mapping ocean currents if you Googled; Nike sneakers plastic toys rubber ducks ocean currents containers, you might find something interesting. I have not and don't intend to but I will tell you that back in the late 1900's, maybe in the 1980s, several containers were lost off ships in the North Pacific. Some contained Nike sneakers and some plastic toys. Both items washed up on shores around the Pacific and I think some even made it into the Atlantic. The sneakers floated low so they reflected Ocean drift but the plastic toys floated high so they reflected a combination of Ocean drift and wind effect.

[High Seas]

Treckers and climbers in NZ (and maybe other places) now carry a locating device with them. Kinda like the ones sometimes used by skiers and folks messing in snow in avalanche areas. The prudent sailor has an EPIRB (emergency positioning locating device) that is registered with appropriate details. Prices have fallen and tech. has improved these greatly. An EPIRB links to SAR satellites and relays position info (circular error based on pass etc) to search and rescue authorities.
The logistics tail for SAR is huge (but presumably worth it).

Might be a bit cheaper to have (risk takers) those in near coastline actiivities carry such equipments. Maybe a waterproof/floating emergency mobile phone could do the same thing? Some of the recent treckers in NZ have been recovered using mobile phone triangulation.

Ocean current mapping - there are some activities using drift bouys and similar tools - but tend to be open ocean - not coastwise. Coastwise mapping might be a very neat idea and they could be recoverable and relaunched/reused. Maybe as simple as a battery pack, gps that is recording., and a BIG reward label.

I recall a few years back the Coast Guard was launching some bouys on Lake Michigan in a SAR effort for a fishing boat - but didn't get any intel on how it was working.

In 10 years of crossing the Pacific and south seas, from a "jandals/sneakers/sandals/filp-flops" perspective -- all I've ever found on the rocks, beach, reefs are LEFT FEET! What Gives There?

[martinw]

QWACK, QWACK

Martin

[thkoutsidthebox]

I made an error in my calculations, I should have written the cost as 3 million, not 10 million. Big differance!

Your right Geof, there are lots of other things to consider, and I wasn't aware of a lot that you mentioned. I haven't researched this, its just a thought. I had considered the wind thing though, and to improve accuracy, the buoy would need to have a comparable amount of its total mass under and over the water as a person floating.

HighSeas, Im guessing from your username you know a lot more about this stuff then me ( Wouldnt be hard! ). I heard about EPIRB's before, but the average swimmer, hiker, bather, child at the beach doesn't have one, and probably never will I think. The mobile phone thing might be a better way to achieve the same aim, but again, everyone will not always have a mobile phone, and it wont always work when someone falls into the ocean.

So from a technical electronics standpoint, whats involved with converting a cheap $99 GPS to become a GPS transmitter?

[martinw]

Originally Posted by thkoutsidthebox So from a technical electronics standpoint, whats involved with converting a cheap $99 GPS to become a GPS transmitter?

Dear thnkoutsidthebox,

I do not know the answer to that one, but I do know that you can buy a GPS module that costs about £40 UK, will communicate on a serial port to a stripped-down PC or PIC, or GSM , and the data can be used to track your path. You can see your journey by superimposing it on Google Earth. It even shows which way you go round a roundabout. Done that.

What exactly is the point?

Strap thousands of the gadgets to the backs of ageing yellow, plastic ducks?

Best wishes

Martin

[High Seas]

Short range ELTs (Emergency Locater/Transmitter) can be quite small - but tend to not have gps integrated. They broadcast on a vhf frequency and are used with a reveiver to locate "the lost". Available commercially - but high cost (as are most marine products). Size: on the order of a mobile phone -- but you need someone to know your out there (and then, they have to have a receiver). These have been used in Man Over Board situations (with some success).
These responses are only directed at locating and possible recovery -- the maping of coastal flow and prediction might be a VERY VERY big effort - and I bet that 3 million is just a start!
It would take a LOT of yellow duckies! (But it could be done).

[martinw]

Originally Posted by High Seas These responses are only directed at locating and possible recovery -- the maping of coastal flow and prediction might be a VERY VERY big effort - and I bet that 3 million is just a start! It would take a LOT of yellow duckies! (But it could be done).

Dear High Seas,

Perhaps you are a sailor with a practical nature, and maybe even an appreciation of the strange nature of the weather.

Safe passage,

Best wishes,

Martin

[Geof]

Originally Posted by High Seas .....In 10 years of crossing the Pacific and south seas, from a "jandals/sneakers/sandals/filp-flops" perspective -- all I've ever found on the rocks, beach, reefs are LEFT FEET! What Gives There?

This is a manifestation of the Coriolis Effect and Symmetry, and also suggests you travel primarily in the South Pacific.

The Coriolis Effect, or Force which is something of a misnomer because no force is involved, as everyone knows cause water to drain out of your bathtub in a right hand vortex in the Northern Hemisphere and a left hand vortex in the Southern Hemisphere.

The Effect comes into play whenever any moves through a change in latitude so sneakers, jandals (haven't heard that name for decades!), whatever when they drift in a Northerly or Southerly direction experience a tendency to move in a curve, left or right handed.

Right handed, or more precisely right footed objects that start moving Southerly experience this lefty Effect so they become cross-threaded and find that this direction of drift is forbidden to them. Something like the Pauli Exclusion Principle. Therefore Right Footed objects may only drift North and Left Footed objects may only drift South.

This preserves the Symmetry of the Universe and suggests the obvious answer to your dilemma. Find a penpal in the Aleutians and swap half your sneakers with them.


Incidentally a shipping container full of rubber duckies is a lot of rubber duckies.

[High Seas]

Martin,
Aye Mate - always seeking a fair passage. We've tried to make so; and it takes bit of preparation and practice. Thanks for the kind thoughts. Our next leg is Malaysia/Thailand to South Africa. Flying and driving is often more scary than passagemaking.
Jim

[martinw]

[QUOTE=
These responses are only directed at locating and possible recovery -- the maping of coastal flow and prediction might be a VERY VERY big effort - and I bet that 3 million is just a start!
It would take a LOT of yellow duckies! (But it could be done).[/QUOTE]

Dear High Seas,

In MVVHO, compared to the true cost of this duck-brained enterprise, 3 million is ..ahem.. a drop in the oceon.

Best wishes

Martin

[martinw]

Well,well,well... I had heard of those ducks before, but it wasn't until I found this
http://www.islandnet.com/~see/weathe...ents/shoes.htm
that I discovered that each and every one of them started their long and lonesome voyages in the company of a green frog, a blue turtle, and a red beaver.

Bless them all.

Best wishes,

Martin