Probably a Daft Question - Life Jackets

[cheshire~rose]

As we allowed the seven feet of fresh water on the Tidal Trent at the weekend save us a little bit of diesel as we went downstream in that torrential rain everyone experienced it made me ponder...

 

How did the self inflating life jackets we were wearing know that they soaking they were getting was from above and not because they were getting a dunking in the river?

 

Can anyone explain this to me?

[Scholar Gypsy]

Not a daft question...

 

Most self-inflating lifejackets now are hydrostatic ie triggered by water pressure, ie going a couple of feet under the water surface, not by getting wet as such.

 

See here

[Dekazer]

Since that one was so easy, here are some more (possibly) daft questions

 

Are these self inflating lifejackets single use only? Or can you somehow get them repacked after being used?

 

Oh, and is there any way of testing that it will work, without dunking it?

 

Thanks,

 

Lucy

[cheshire~rose]

Thanks Scholar!

 

They can be repacked and a new cannister put in.

 

We had some stowed in a locker when Python took on water and one went off! (it was very hard to remove it from the locker!) but it was all put back together and a new cannister put in it. In fact for all I know that might have been the one I was wearing at the weekend because we had "borrowed" Python's

[Naughty Cal]

You can self inflate them to check they are airtight and you can rearm them with new firing mechanisms when they do go off.

 

There are two options with the firing mechanisms. One works in pressure the other is a material that dissolves, when it is gone the mechanism fires. Obviously the one working on pressure is less liable to firing when not needed.

[Timleech]

Since that one was so easy, here are some more (possibly) daft questions

 

Are these self inflating lifejackets single use only? Or can you somehow get them repacked after being used?

 

Oh, and is there any way of testing that it will work, without dunking it?

 

Thanks,

 

Lucy

 

 

Read

http://rnli.org/SiteCollectionDocuments/Caring%20for%20your%20Lifejacket.pdf

for some guidance.

 

Tim

[Phil Ambrose]

As a rule the self inflating life jackets can be re-armed, you can buy a kit so no they are not single use and as far as I know you cannot test them other than a visual check on the "firing" mechanism. Normaly they also have a manual firing mechanism, usually a pull cord plus they can be inflated by mouth via a tube so that in the event of the hgas cylider failing to inflate sufficiently you can do so simply by blowing into the tube.

Phil

[Naughty Cal]

Also worth noting that the firing mechanisms have a shelf life of about two years so do need replacing every couple of years. Ideal time to set one off to experience it prior to needing it in anger!

[Thorfast]

When we are sailing Draken Harald Hårfagre the crew all check the small gas canister to see if it is still sealed every time they put on a lifejacket...a good practice to adopt. And we put new canisters in every year regardless.

[johnmck]

Funnily enough just been looking at this kit for ours. http://www.lifejackets.co.uk/products/104/united-moulders-automatic-rearming-kit-33g

 

Although I have been told that if the canister is intact, all you need to replace is this part. http://www.lifejackets.co.uk/products/107/united-moulders-cartridge-and-clip-set

 

As the second part is the one stamped with the expiry date.

Edited May 27, 2014 by johnmck

[ditchcrawler]

When we are sailing Draken Harald Hårfagre the crew all check the small gas canister to see if it is still sealed every time they put on a lifejacket...a good practice to adopt. And we put new canisters in every year regardless.

Weighing them is best, you can get a hole smaller than a pin hole in the seal and over a few months they will leak away. You can do it with kitchen scales.

This is from personal experience.

[John V]

Most places that do liferaft repair/maintenance check and maintain lifejackets as commercial ones need to be checked on a regular basis

[johnmck]

Just for info, found the below. Seems to suggest there may be a fault with some of the cartridges, so worth checking yours for a free replacement.

 

http://www.uml.co.uk/cartridge_check_english.html

 

States those with an expiry date 08/2014 are the ones, so check yours!

Edited May 28, 2014 by johnmck

[Trousers1000]

Please see other threads that are more recent on all matters lifejackets.

I'm very happy to help as I both design lifejackets and work internally on sea survival equip,met