EPIRB launcher
 

Anyone have any knowledge or experience with the hydrostatic release
module that is inside the case that launches the EPIRB when the boat is
sinking? Specifically the one I am inquiring about is the Hammar model
H20 E. It says on the top that you should replace after 2 years of
"use", but what if the unit was manufactured longer than a few years
prior? If the manufacture date is 2005, but has been deployed in the
case for only one year since purchase - would the unit still be good and
reliable? I am not familiar with the internal workings of these units,
are they a form of explosive charge (making them more susceptible to
failures over time similar to flares), or just spring loaded? Any other
info I should know? Thanks
Red

EPIRB launcher
 

On 2008-01-18 02:15:50 -0500, Red said:

Anyone have any knowledge or experience with the hydrostatic release
module that is inside the case that launches the EPIRB when the boat is
sinking? Specifically the one I am inquiring about is the Hammar model
H20 E.

That's something I'd go to the manufacturer with, possibly to a good
independent technician if such exist. My impression is that these
things are built to absolutely positively function (as much as can be
humanly possible) within the time periods mentioned. Their backside is
on the line big time if their units don't perform to their stated
claims....

I *suspect* that the clock didn't tick on the launching mechanism while
it was in a climate controlled environment that limited corrosion and
also that it's probably safe for easily double the stated time period,
but it's up to you to trust my assessment of a unit I haven't actually
examined.

--
Jere Lull
Tanzer 28 #4 out of Tolchester, MD
Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/

EPIRB launcher
 

Red wrote in :

Anyone have any knowledge or experience with the hydrostatic release
module that is inside the case that launches the EPIRB when the boat is
sinking? Specifically the one I am inquiring about is the Hammar model
H20 E. It says on the top that you should replace after 2 years of
"use", but what if the unit was manufactured longer than a few years
prior? If the manufacture date is 2005, but has been deployed in the
case for only one year since purchase - would the unit still be good and
reliable? I am not familiar with the internal workings of these units,
are they a form of explosive charge (making them more susceptible to
failures over time similar to flares), or just spring loaded? Any other
info I should know? Thanks
Red

I have one of these and have found the replacement hydrostatic release part
on the Internet. This is the same part that I have on my liferaft.

I believe that it's a mechanical part with a sharp blade that cuts the
rubber retaining rob in the EPIRB unit and (I think) a line for the life
raft. I tend to replace them every 2 years. They aren't cheap.

I've taken an old unit diving with me to see if it would "fire". It did
and there wasn't any explosive sound. I suspect that it's a pressure
activated release on a spring. The problem is that there's no way to
inspect it and it's a one time use device.

-- Geoff
www.GeoffSchultz.org

EPIRB launcher
 

"Geoff Schultz" wrote in message
.. .
Red wrote in :

Anyone have any knowledge or experience with the hydrostatic release
module that is inside the case that launches the EPIRB when the boat is
sinking? Specifically the one I am inquiring about is the Hammar model
H20 E. It says on the top that you should replace after 2 years of
"use", but what if the unit was manufactured longer than a few years
prior? If the manufacture date is 2005, but has been deployed in the
case for only one year since purchase - would the unit still be good and
reliable? I am not familiar with the internal workings of these units,
are they a form of explosive charge (making them more susceptible to
failures over time similar to flares), or just spring loaded? Any other
info I should know? Thanks
Red

I have one of these and have found the replacement hydrostatic release
part
on the Internet. This is the same part that I have on my liferaft.

I believe that it's a mechanical part with a sharp blade that cuts the
rubber retaining rob in the EPIRB unit and (I think) a line for the life
raft. I tend to replace them every 2 years. They aren't cheap.

I've taken an old unit diving with me to see if it would "fire". It did
and there wasn't any explosive sound. I suspect that it's a pressure
activated release on a spring. The problem is that there's no way to
inspect it and it's a one time use device.

-- Geoff
www.GeoffSchultz.org


Isn't that the definition of hydrostatic... pressure release?


--
"j" ganz @@
www.sailnow.com

EPIRB launcher
 

On 2008-01-18 02:15:50 -0500, Red said:

Anyone have any knowledge or experience with the hydrostatic release
module that is inside the case that launches the EPIRB when the boat is
sinking? Specifically the one I am inquiring about is the Hammar model
H20 E.


That's something I'd go to the manufacturer with, possibly to a good
independent technician if such exist. My impression is that these things
are built to absolutely positively function (as much as can be humanly
possible) within the time periods mentioned. Their backside is on the
line big time if their units don't perform to their stated claims....

I *suspect* that the clock didn't tick on the launching mechanism while
it was in a climate controlled environment that limited corrosion and
also that it's probably safe for easily double the stated time period,
but it's up to you to trust my assessment of a unit I haven't actually
examined.

--
Jere Lull


I have been trying to convince the owner of the EPIRB to get a new one
to be safe, but it has been service only one year so he seems to be
opting for keeping this one till the end of the season. That would not
be my choice.
Red

EPIRB launcher
 

I have one of these and have found the replacement hydrostatic release part
on the Internet. This is the same part that I have on my liferaft.

I believe that it's a mechanical part with a sharp blade that cuts the
rubber retaining rob in the EPIRB unit and (I think) a line for the life
raft. I tend to replace them every 2 years. They aren't cheap.

I've taken an old unit diving with me to see if it would "fire". It did
and there wasn't any explosive sound. I suspect that it's a pressure
activated release on a spring. The problem is that there's no way to
inspect it and it's a one time use device.

-- Geoff
www.GeoffSchultz.org

Geoff,
There is no rubber retainer in the EPIRB housing. The release module has
a pin that sticks through the front of the container that you can push
to deploy the EPIRB manually, or the water pressure releases the pin
when the boat sinks. When the pin is released it in turn releases a
long, flat spring along the bottom of the case that pushes the EPIRB out
of the case. I just didn't know what the module uses to release the pin,
and if that mechanism degrades over time. In either case I've advised
the owner to replace it, but at this time I believe he will keep it till
the end of the season.
Red

EPIRB launcher
 

Ok, I've got some answers from some survival gear outfits. I'm told that
the service life on the release module is two years "in service"
regardless of manufacture date (providing its not *too* old) as long as
it is in good condition. So if it was manufactured in 2005 but purchased
in spring 2007 and put in service at that time, then it would be good to
go through spring 2009. The price I got on one was $147 plus shipping -
didn't check the net for it yet.
Red

EPIRB launcher
 

"Capt. JG" wrote in
:

"Geoff Schultz" wrote in message
.. .
Red wrote in
:

Anyone have any knowledge or experience with the hydrostatic release
module that is inside the case that launches the EPIRB when the boat
is sinking? Specifically the one I am inquiring about is the Hammar
model H20 E. It says on the top that you should replace after 2
years of "use", but what if the unit was manufactured longer than a
few years prior? If the manufacture date is 2005, but has been
deployed in the case for only one year since purchase - would the
unit still be good and reliable? I am not familiar with the internal
workings of these units, are they a form of explosive charge (making
them more susceptible to failures over time similar to flares), or
just spring loaded? Any other info I should know? Thanks
Red

I have one of these and have found the replacement hydrostatic
release part
on the Internet. This is the same part that I have on my liferaft.

I believe that it's a mechanical part with a sharp blade that cuts
the rubber retaining rob in the EPIRB unit and (I think) a line for
the life raft. I tend to replace them every 2 years. They aren't
cheap.

I've taken an old unit diving with me to see if it would "fire". It
did and there wasn't any explosive sound. I suspect that it's a
pressure activated release on a spring. The problem is that there's
no way to inspect it and it's a one time use device.

-- Geoff
www.GeoffSchultz.org


Isn't that the definition of hydrostatic... pressure release?

Yes it is, and I was simply stating that it wasn't an explosive charge and
instead a mechanical cutting device triggered by pressure. I'm not quite
sure what point you were trying to make other than perhaps to be a smartass
and not add anything to the discussion.

-- Geoff
www.GeoffSchultz.org

EPIRB launcher
 

Red wrote in
:

I have one of these and have found the replacement hydrostatic release
part on the Internet. This is the same part that I have on my
liferaft.

I believe that it's a mechanical part with a sharp blade that cuts the
rubber retaining rob in the EPIRB unit and (I think) a line for the
life raft. I tend to replace them every 2 years. They aren't cheap.

I've taken an old unit diving with me to see if it would "fire". It
did and there wasn't any explosive sound. I suspect that it's a
pressure activated release on a spring. The problem is that there's
no way to inspect it and it's a one time use device.

-- Geoff
www.GeoffSchultz.org

Geoff,
There is no rubber retainer in the EPIRB housing. The release module
has a pin that sticks through the front of the container that you can
push to deploy the EPIRB manually, or the water pressure releases the
pin when the boat sinks. When the pin is released it in turn releases
a long, flat spring along the bottom of the case that pushes the EPIRB
out of the case. I just didn't know what the module uses to release
the pin, and if that mechanism degrades over time. In either case I've
advised the owner to replace it, but at this time I believe he will
keep it till the end of the season.
Red


We may have different units. Mine is from about 1997 and it has a rubber
rod that restrains spring and the cover. This rod is cut by the
hydrostatic release, allowing the cover to come off and and spring to push
the EPIRB out of the case.

Since you're just going to trash the hydrostatic release, tie a string to
it and drop it into some deep water and see if it works. I think that
they're supposed to go off at 13'.

-- Geoff
www.GeoffSchultz.org

EPIRB launcher
 

On Jan 18, 8:16 am, Geoff Schultz wrote:
...Since you're just going to trash the hydrostatic release, tie a string to
it and drop it into some deep water and see if it works. I think that
they're supposed to go off at 13'. ...

I disassembled one that I'd replaced after 5 years of cruising and it
looked brand new inside and worked perfectly... I suppose they're
worried about the mechanism getting fouled by salt or something...
Anyway, FWIW it was easy to take apart and put back together.

-- Tom.

EPIRB launcher
 

"Geoff Schultz" wrote in message
.. .
"Capt. JG" wrote in
:

"Geoff Schultz" wrote in message
.. .
Red wrote in
:

Anyone have any knowledge or experience with the hydrostatic release
module that is inside the case that launches the EPIRB when the boat
is sinking? Specifically the one I am inquiring about is the Hammar
model H20 E. It says on the top that you should replace after 2
years of "use", but what if the unit was manufactured longer than a
few years prior? If the manufacture date is 2005, but has been
deployed in the case for only one year since purchase - would the
unit still be good and reliable? I am not familiar with the internal
workings of these units, are they a form of explosive charge (making
them more susceptible to failures over time similar to flares), or
just spring loaded? Any other info I should know? Thanks
Red

I have one of these and have found the replacement hydrostatic
release part
on the Internet. This is the same part that I have on my liferaft.

I believe that it's a mechanical part with a sharp blade that cuts
the rubber retaining rob in the EPIRB unit and (I think) a line for
the life raft. I tend to replace them every 2 years. They aren't
cheap.

I've taken an old unit diving with me to see if it would "fire". It
did and there wasn't any explosive sound. I suspect that it's a
pressure activated release on a spring. The problem is that there's
no way to inspect it and it's a one time use device.

-- Geoff
www.GeoffSchultz.org


Isn't that the definition of hydrostatic... pressure release?

Yes it is, and I was simply stating that it wasn't an explosive charge and
instead a mechanical cutting device triggered by pressure. I'm not quite
sure what point you were trying to make other than perhaps to be a
smartass
and not add anything to the discussion.

-- Geoff
www.GeoffSchultz.org


Well Geoff, it seemed to me that you were asking if a hydrostatic device is
a pressure release mechanism. I suppose it's possible for this to actuate
something other than a spring, but that seems overly complicated. What did
you think it would activate?

That was my point, which if you'd have stated your question a bit more
clearly, would have contributed a great deal more to the discussion.

--
"j" ganz @@
www.sailnow.com

EPIRB launcher
 

"Capt. JG" wrote in
:

"Geoff Schultz" wrote in message
.. .
"Capt. JG" wrote in
:

"Geoff Schultz" wrote in message
.. .
Red wrote in
:

Anyone have any knowledge or experience with the hydrostatic
release module that is inside the case that launches the EPIRB
when the boat is sinking? Specifically the one I am inquiring
about is the Hammar model H20 E. It says on the top that you
should replace after 2 years of "use", but what if the unit was
manufactured longer than a few years prior? If the manufacture
date is 2005, but has been deployed in the case for only one year
since purchase - would the unit still be good and reliable? I am
not familiar with the internal workings of these units, are they a
form of explosive charge (making them more susceptible to failures
over time similar to flares), or just spring loaded? Any other
info I should know? Thanks Red

I have one of these and have found the replacement hydrostatic
release part
on the Internet. This is the same part that I have on my liferaft.

I believe that it's a mechanical part with a sharp blade that cuts
the rubber retaining rob in the EPIRB unit and (I think) a line for
the life raft. I tend to replace them every 2 years. They aren't
cheap.

I've taken an old unit diving with me to see if it would "fire".
It did and there wasn't any explosive sound. I suspect that it's a
pressure activated release on a spring. The problem is that
there's no way to inspect it and it's a one time use device.

-- Geoff
www.GeoffSchultz.org


Isn't that the definition of hydrostatic... pressure release?

Yes it is, and I was simply stating that it wasn't an explosive
charge and instead a mechanical cutting device triggered by pressure.
I'm not quite sure what point you were trying to make other than
perhaps to be a smartass
and not add anything to the discussion.

-- Geoff
www.GeoffSchultz.org


Well Geoff, it seemed to me that you were asking if a hydrostatic
device is a pressure release mechanism. I suppose it's possible for
this to actuate something other than a spring, but that seems overly
complicated. What did you think it would activate?

That was my point, which if you'd have stated your question a bit more
clearly, would have contributed a great deal more to the discussion.

I think that you're confusing me with the OP. I haven't asked any
questions. The closest thing to a question was my statement "I suspect
that it's a pressure activated release on a spring." Not having opened
one up, I wasn't sure how it operated, but I certainly understood that
hydrostatic is a synonym for "pressure activated."

-- Geoff
www.GeoffSchultz.org

EPIRB launcher
 

"Geoff Schultz" wrote in message
...
"Capt. JG" wrote in
:

"Geoff Schultz" wrote in message
.. .
"Capt. JG" wrote in
:

"Geoff Schultz" wrote in message
.. .
Red wrote in
:

Anyone have any knowledge or experience with the hydrostatic
release module that is inside the case that launches the EPIRB
when the boat is sinking? Specifically the one I am inquiring
about is the Hammar model H20 E. It says on the top that you
should replace after 2 years of "use", but what if the unit was
manufactured longer than a few years prior? If the manufacture
date is 2005, but has been deployed in the case for only one year
since purchase - would the unit still be good and reliable? I am
not familiar with the internal workings of these units, are they a
form of explosive charge (making them more susceptible to failures
over time similar to flares), or just spring loaded? Any other
info I should know? Thanks Red

I have one of these and have found the replacement hydrostatic
release part
on the Internet. This is the same part that I have on my liferaft.

I believe that it's a mechanical part with a sharp blade that cuts
the rubber retaining rob in the EPIRB unit and (I think) a line for
the life raft. I tend to replace them every 2 years. They aren't
cheap.

I've taken an old unit diving with me to see if it would "fire".
It did and there wasn't any explosive sound. I suspect that it's a
pressure activated release on a spring. The problem is that
there's no way to inspect it and it's a one time use device.

-- Geoff
www.GeoffSchultz.org


Isn't that the definition of hydrostatic... pressure release?

Yes it is, and I was simply stating that it wasn't an explosive
charge and instead a mechanical cutting device triggered by pressure.
I'm not quite sure what point you were trying to make other than
perhaps to be a smartass
and not add anything to the discussion.

-- Geoff
www.GeoffSchultz.org


Well Geoff, it seemed to me that you were asking if a hydrostatic
device is a pressure release mechanism. I suppose it's possible for
this to actuate something other than a spring, but that seems overly
complicated. What did you think it would activate?

That was my point, which if you'd have stated your question a bit more
clearly, would have contributed a great deal more to the discussion.

I think that you're confusing me with the OP. I haven't asked any
questions. The closest thing to a question was my statement "I suspect
that it's a pressure activated release on a spring." Not having opened
one up, I wasn't sure how it operated, but I certainly understood that
hydrostatic is a synonym for "pressure activated."

-- Geoff
www.GeoffSchultz.org


Ah... glad you understood. Sorry if my post seemed smartass-like... wasn't
my intention, although I am pretty good at it from time to time.

--
"j" ganz @@
www.sailnow.com

EPIRB launcher
 

" wrote in
:

On Jan 18, 8:16 am, Geoff Schultz wrote:
...Since you're just going to trash the hydrostatic release, tie a
string to it and drop it into some deep water and see if it works. I
think that they're supposed to go off at 13'. ...

I disassembled one that I'd replaced after 5 years of cruising and it
looked brand new inside and worked perfectly... I suppose they're
worried about the mechanism getting fouled by salt or something...
Anyway, FWIW it was easy to take apart and put back together.

-- Tom.

Inquiring minds want to know: What was in the inside?


-- Geoff
www.GeoffSchultz.org

EPIRB launcher
 

Red wrote in :

Ok, I've got some answers from some survival gear outfits. I'm told that
the service life on the release module is two years "in service"
regardless of manufacture date (providing its not *too* old) as long as
it is in good condition. So if it was manufactured in 2005 but purchased
in spring 2007 and put in service at that time, then it would be good to
go through spring 2009. The price I got on one was $147 plus shipping -
didn't check the net for it yet.
Red

You can get them for about $75 at http://www.marinewholesales.com/


-- Geoff
www.GeoffSchultz.org

EPIRB launcher
 

On Jan 19, 1:48 am, Geoff Schultz wrote:
....
Inquiring minds want to know: What was in the inside? ...

As I recall, there's a gasket / diaphragm, two springs a blade and
blade retainer. I'll dive into my spare parts cabinet and look at it
again if I get some time.

-- Tom.

EPIRB launcher
 

On Jan 19, 9:30 am, " wrote:
... I'll dive into my spare parts cabinet and look at it
again if I get some time. ...


Right, I just took it apart and put it back together. It is a Hammar
H20 E "for EPIRB use only". The insides are pretty much as I
remembered them. The major working parts are a knife and spring held
in place by a pin that is attached to a diaphragm that is held in
place by another spring. When it operates water pushes against the
diaphragm through two hollow pins on the knife side of the device
forcing the diaphragm into the low pressure chamber thus pulling the
retaining pin out and releasing the knife. The one I have sat in my
EPIRB in my cockpit for years and looks and operates like new.

There is one mysterious feature. On the top of the pressure casing
there is a small resin colored plug. It is visible from the outside
of the case through a hole in the label. I presume this keeps the
device from exploding if you take it up into space or something. On
the other hand it could be the little bit that dissolves every two
years so you have to replace it... Or, perhaps, they use the hole to
fill the chamber with inert gas... In any case, if the bung were out
the device would not operate. I suppose it is worth looking to make
sure it is there periodically, particularly if the release has been in
an airplane.

-- Tom.

EPIRB launcher
 

On Sat, 19 Jan 2008 17:25:39 -0800 (PST), "
wrote:

... The major working parts are a knife and spring held
in place by a pin that is attached to a diaphragm that is held in
place by another spring. When it operates water pushes against the
diaphragm through two hollow pins on the knife side of the device
forcing the diaphragm into the low pressure chamber thus pulling the
retaining pin out and releasing the knife.
There is one mysterious feature. On the top of the pressure casing
there is a small resin colored plug. It is visible from the outside
of the case through a hole in the label. I presume this keeps the
device from exploding if you take it up into space or something. ...
I suppose it is worth looking to make
sure it is there periodically, particularly if the release has been in
an airplane.

-- Tom.


...er.... It takes about 6 psi EXCESS pressure like 13 ft depth of
water to actuate the sprung knife?

Clear on up to outer space, there is no excess pressure I know of.
Or am I misssing something?

Brian W

EPIRB launcher
 

You can get them for about $75 at http://www.marinewholesales.com/

-- Geoff
www.GeoffSchultz.org

Thanks Geoff,
I looked it up and they are about half of the quoted retail out here. I
will send the owner this link then and let him take care of it.
Red

EPIRB launcher
 

...er.... It takes about 6 psi EXCESS pressure like 13 ft depth of
water to actuate the sprung knife?

Clear on up to outer space, there is no excess pressure I know of.
Or am I misssing something?

Brian W

I take it he meant that it may be there to release pressure *inside* the
case to keep the case from "exploding" in a low pressure environment,
not imploding as would be the case of external pressure when sinking.
Red

EPIRB launcher
 

On Jan 19, 7:15 pm, Red wrote:
....
I take it he meant that it may be there to release pressure *inside* the
case to keep the case from "exploding" in a low pressure environment,
not imploding as would be the case of external pressure when sinking.
Red

Yes, that's exactly what I was trying to say. It is a curious feature
and I'm just speculating about its purpose. Maybe it's for something
else.

-- Tom.

EPIRB launcher
 

On Sat, 19 Jan 2008 17:25:39 -0800 (PST), "
wrote:


There is one mysterious feature. On the top of the pressure casing
there is a small resin colored plug.

Obviously :-) a porous plug which equalizes pressure when dry and does
not do so when wet.

It is visible from the outside
of the case through a hole in the label. I presume this keeps the
device from exploding if you take it up into space or something. On
the other hand it could be the little bit that dissolves every two
years so you have to replace it... Or, perhaps, they use the hole to
fill the chamber with inert gas... In any case, if the bung were out
the device would not operate. I suppose it is worth looking to make
sure it is there periodically, particularly if the release has been in
an airplane.

-- Tom.

EPIRB launcher
 

On Sun, 20 Jan 2008 00:15:08 -0500, Red wrote:

..er.... It takes about 6 psi EXCESS pressure like 13 ft depth of
water to actuate the sprung knife?

Clear on up to outer space, there is no excess pressure I know of.
Or am I missing something?

Brian W

I take it he meant that it may be there to release pressure *inside* the
case to keep the case from "exploding" in a low pressure environment,
not imploding as would be the case of external pressure when sinking.
Red


Yes, I see that possibility now.
In practice, containers can usually take several times more
internal over-pressure than internal under-pressure.
Take a look at your clear plastic soda bottle. It may go higher than
60 psi before going bang, but 2 or 3 psi from outside will do a number
on collapsing it.

Brian Whatcott Altus OK

EPIRB launcher
 

On Sun, 20 Jan 2008 11:02:16 +0000, Goofball_star_dot_etal
wrote:

On Sat, 19 Jan 2008 17:25:39 -0800 (PST), "
wrote:


There is one mysterious feature. On the top of the pressure casing
there is a small resin colored plug.

Obviously :-) a porous plug which equalizes pressure when dry and does
not do so when wet.


Thinking about that....if the leakage rate is slow, wet or dry,
then that would work for a hydrostatic release container which might
sink 13 feet in less than say 30 minutes....

Brian Whatcott Altus OK

EPIRB launcher
 

On Jan 20, 1:02 am, Goofball_star_dot_etal
wrote:

Obviously :-) a porous plug which equalizes pressure when dry and does
not do so when wet.

That sounds reasonable and I suppose it would make the release depths
more consistent. For me the big question is, is this the bit that
goes bad in two years? As I've mentioned, mine was manufactured in
march of 2000 and it sat in my EPIRB case for years and I just
disassembled and inspected it yesterday and it looked absolutely
perfect...

-- Tom.