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[email protected] March 14th 09 01:53 PM

New safety item
 
One of the regulars on an email list I belong to just posted this:

************************************************** ********
The local coast guard came down to a boat which had hit a rock with a
can of foam-in-place. If you can slow the leak down somehow you can
fire that into the bilge or wherever and it will hold the water back
long enough for you to get somewhere. It is tenaciously gooey. I'm
planning on putting a can onboard.
************************************************** ********


Capt. JG March 14th 09 02:45 PM

New safety item
 
wrote in message
...
One of the regulars on an email list I belong to just posted this:

************************************************** ********
The local coast guard came down to a boat which had hit a rock with a
can of foam-in-place. If you can slow the leak down somehow you can
fire that into the bilge or wherever and it will hold the water back
long enough for you to get somewhere. It is tenaciously gooey. I'm
planning on putting a can onboard.
************************************************** ********



Interesting...

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




Keith nuttle March 14th 09 03:52 PM

New safety item
 
Capt. JG wrote:
wrote in message
...
One of the regulars on an email list I belong to just posted this:

************************************************** ********
The local coast guard came down to a boat which had hit a rock with a
can of foam-in-place. If you can slow the leak down somehow you can
fire that into the bilge or wherever and it will hold the water back
long enough for you to get somewhere. It is tenaciously gooey. I'm
planning on putting a can onboard.
************************************************** ********



Interesting...

If you read the about the exploration trips of the 1500's to 1800's one
of the techniques to save the ship was to rig a canvas patch over the
hole. The technique was used when a ship hit the rocks or when a cannon
ball holed the ship below the water line.

The foam sounds like a good substitute for canvas, and would probable
provide a better seal. Wish I had thought of it and I hope I will never
have to use it.

Larry March 14th 09 04:11 PM

New safety item
 
Keith Nuttle wrote in news:gpQul.26263
:

If you read the about the exploration trips of the 1500's to 1800's one
of the techniques to save the ship was to rig a canvas patch over the
hole. The technique was used when a ship hit the rocks or when a cannon
ball holed the ship below the water line.

The foam sounds like a good substitute for canvas, and would probable
provide a better seal. Wish I had thought of it and I hope I will never
have to use it.


Navy DC school taught how to block holes in the hull so the pumps could
keep up with the leakage. Once the hole was packed with an internal dam of
wood, mattresses and whatever else would slow the flooding, canvas was
dived over the side to let the seawater pressure force it into the hole as
a sort of flapper valve. I don't see how you could get underway and keep
the canvas in place, though.....without tearing off the canvas.

We nearly drown in DC school trying to get the damned water to stop
flooding the training compartment before we ran out of airspace to breathe.
You work very hard in such a desparate situation as flooding a sealed
compartment......even harder than I did in fire fighting school pushed into
the totally dark, smoke filled compartment trying to put out the fire with
foam and spray.

The damned chief lit the diesel fire and then just stood there talking and
talking about how we were going to put it out as the flames got bigger and
bigger and HUGE! Suddenly, he simply stood aside and said, "Don't look at
me, gentlemen.....After you...", gesturing towards the watertight hatch,
which by now was so hot it was smoking, itself. We could hardly cool the
damned door, talk nothing of putting out the fire....most enlightening....

Sitting in the cockpit, alone on midwatch, of some sailboat, I've often had
flashbacks of that training while we're 100 miles offshore with no
firefighting equipment bigger than a 5# extinguisher. That won't do
anything for a fiberglass fire other than make it mad....


HPEER March 15th 09 02:30 PM

New safety item
 
Larry wrote:
Keith Nuttle wrote in news:gpQul.26263
:

If you read the about the exploration trips of the 1500's to 1800's one
of the techniques to save the ship was to rig a canvas patch over the
hole. The technique was used when a ship hit the rocks or when a cannon
ball holed the ship below the water line.

The foam sounds like a good substitute for canvas, and would probable
provide a better seal. Wish I had thought of it and I hope I will never
have to use it.


Navy DC school taught how to block holes in the hull so the pumps could
keep up with the leakage. Once the hole was packed with an internal dam of
wood, mattresses and whatever else would slow the flooding, canvas was
dived over the side to let the seawater pressure force it into the hole as
a sort of flapper valve. I don't see how you could get underway and keep
the canvas in place, though.....without tearing off the canvas.

We nearly drown in DC school trying to get the damned water to stop
flooding the training compartment before we ran out of airspace to breathe.
You work very hard in such a desparate situation as flooding a sealed
compartment......even harder than I did in fire fighting school pushed into
the totally dark, smoke filled compartment trying to put out the fire with
foam and spray.

The damned chief lit the diesel fire and then just stood there talking and
talking about how we were going to put it out as the flames got bigger and
bigger and HUGE! Suddenly, he simply stood aside and said, "Don't look at
me, gentlemen.....After you...", gesturing towards the watertight hatch,
which by now was so hot it was smoking, itself. We could hardly cool the
damned door, talk nothing of putting out the fire....most enlightening....

Sitting in the cockpit, alone on midwatch, of some sailboat, I've often had
flashbacks of that training while we're 100 miles offshore with no
firefighting equipment bigger than a 5# extinguisher. That won't do
anything for a fiberglass fire other than make it mad....


Those canvas thingies are called "collision mats."

I've been thinking along these lines myself. For stuff you can get to
you can use a wax toilet ring. I think Bruce mentioned that a while
back somewhere. Then you can have a bag (or two) of cement on board to
back up the hole. Weight as much as anything I guess. I know that
Moitessier carried some kind of special cement. Mixed with clay I
think. I have at times mixed plaster with mortar and it can make a
pretty fast setting mix. (Why you ask? My fist wife, delicate flower
that she was, once kicked a hole in the bathroom wall in a fit. (No I
was not home nor do I know the cause.) But the mortar/plaster fix
"fixed" the problem. She never did it again.)

Back to the foam. I have a steel boat and the aft half of my keel is
hollow and too deep for me to reach into. I can't reach about the last
foot. The top of the keel extends up so that the sole rests on it and
the hull is welded to the keel all around. My fear was that somehow I
would hole the keel and not be able to control the leak. I had thought
of pouring foam in but don't want to loose the storage space.

I sometimes use Great Stuff, sparyed into plastic shopping bags to
stabalize things, like my holding tank. Keep it firmly in place. The
problem with that is that it takes a while to set up. To long in time
of emergency. Ideally you would have some Great Stuff that would set up
in 2 or 3 minutes. You could spray it into some kind of baggie and
then, once it is nearly hard, cram it over the opening, backed up by
something (cement or sole) and the foal would push into the opening.

Keith nuttle March 15th 09 03:56 PM

New safety item
 
HPEER wrote:
Larry wrote:
Keith Nuttle wrote in news:gpQul.26263
:

If you read the about the exploration trips of the 1500's to 1800's
one of the techniques to save the ship was to rig a canvas patch over
the hole. The technique was used when a ship hit the rocks or when a
cannon ball holed the ship below the water line.

The foam sounds like a good substitute for canvas, and would probable
provide a better seal. Wish I had thought of it and I hope I will
never have to use it.


Navy DC school taught how to block holes in the hull so the pumps
could keep up with the leakage. Once the hole was packed with an
internal dam of wood, mattresses and whatever else would slow the
flooding, canvas was dived over the side to let the seawater pressure
force it into the hole as a sort of flapper valve. I don't see how
you could get underway and keep the canvas in place,
though.....without tearing off the canvas.

We nearly drown in DC school trying to get the damned water to stop
flooding the training compartment before we ran out of airspace to
breathe. You work very hard in such a desparate situation as flooding
a sealed compartment......even harder than I did in fire fighting
school pushed into the totally dark, smoke filled compartment trying
to put out the fire with foam and spray.

The damned chief lit the diesel fire and then just stood there talking
and talking about how we were going to put it out as the flames got
bigger and bigger and HUGE! Suddenly, he simply stood aside and said,
"Don't look at me, gentlemen.....After you...", gesturing towards the
watertight hatch, which by now was so hot it was smoking, itself. We
could hardly cool the damned door, talk nothing of putting out the
fire....most enlightening....

Sitting in the cockpit, alone on midwatch, of some sailboat, I've
often had flashbacks of that training while we're 100 miles offshore
with no firefighting equipment bigger than a 5# extinguisher. That
won't do anything for a fiberglass fire other than make it mad....


Those canvas thingies are called "collision mats."

I've been thinking along these lines myself. For stuff you can get to
you can use a wax toilet ring. I think Bruce mentioned that a while
back somewhere. Then you can have a bag (or two) of cement on board to
back up the hole. Weight as much as anything I guess. I know that
Moitessier carried some kind of special cement. Mixed with clay I
think. I have at times mixed plaster with mortar and it can make a
pretty fast setting mix. (Why you ask? My fist wife, delicate flower
that she was, once kicked a hole in the bathroom wall in a fit. (No I
was not home nor do I know the cause.) But the mortar/plaster fix
"fixed" the problem. She never did it again.)

Back to the foam. I have a steel boat and the aft half of my keel is
hollow and too deep for me to reach into. I can't reach about the last
foot. The top of the keel extends up so that the sole rests on it and
the hull is welded to the keel all around. My fear was that somehow I
would hole the keel and not be able to control the leak. I had thought
of pouring foam in but don't want to loose the storage space.

I sometimes use Great Stuff, sparyed into plastic shopping bags to
stabalize things, like my holding tank. Keep it firmly in place. The
problem with that is that it takes a while to set up. To long in time
of emergency. Ideally you would have some Great Stuff that would set up
in 2 or 3 minutes. You could spray it into some kind of baggie and
then, once it is nearly hard, cram it over the opening, backed up by
something (cement or sole) and the foal would push into the opening.


In the 1500's to 1800's there was no such thing as a collision mat. As
I remember what I have read they took the extra sails and used them to
close the holes.

Capt. JG March 15th 09 05:43 PM

New safety item
 
"Keith Nuttle" wrote in message
...
HPEER wrote:
Larry wrote:
Keith Nuttle wrote in news:gpQul.26263
:

If you read the about the exploration trips of the 1500's to 1800's one
of the techniques to save the ship was to rig a canvas patch over the
hole. The technique was used when a ship hit the rocks or when a
cannon ball holed the ship below the water line.

The foam sounds like a good substitute for canvas, and would probable
provide a better seal. Wish I had thought of it and I hope I will
never have to use it.


Navy DC school taught how to block holes in the hull so the pumps could
keep up with the leakage. Once the hole was packed with an internal dam
of wood, mattresses and whatever else would slow the flooding, canvas
was dived over the side to let the seawater pressure force it into the
hole as a sort of flapper valve. I don't see how you could get underway
and keep the canvas in place, though.....without tearing off the canvas.

We nearly drown in DC school trying to get the damned water to stop
flooding the training compartment before we ran out of airspace to
breathe. You work very hard in such a desparate situation as flooding a
sealed compartment......even harder than I did in fire fighting school
pushed into the totally dark, smoke filled compartment trying to put out
the fire with foam and spray.

The damned chief lit the diesel fire and then just stood there talking
and talking about how we were going to put it out as the flames got
bigger and bigger and HUGE! Suddenly, he simply stood aside and said,
"Don't look at me, gentlemen.....After you...", gesturing towards the
watertight hatch, which by now was so hot it was smoking, itself. We
could hardly cool the damned door, talk nothing of putting out the
fire....most enlightening....

Sitting in the cockpit, alone on midwatch, of some sailboat, I've often
had flashbacks of that training while we're 100 miles offshore with no
firefighting equipment bigger than a 5# extinguisher. That won't do
anything for a fiberglass fire other than make it mad....


Those canvas thingies are called "collision mats."

I've been thinking along these lines myself. For stuff you can get to
you can use a wax toilet ring. I think Bruce mentioned that a while back
somewhere. Then you can have a bag (or two) of cement on board to back
up the hole. Weight as much as anything I guess. I know that Moitessier
carried some kind of special cement. Mixed with clay I think. I have at
times mixed plaster with mortar and it can make a pretty fast setting
mix. (Why you ask? My fist wife, delicate flower that she was, once
kicked a hole in the bathroom wall in a fit. (No I was not home nor do I
know the cause.) But the mortar/plaster fix "fixed" the problem. She
never did it again.)

Back to the foam. I have a steel boat and the aft half of my keel is
hollow and too deep for me to reach into. I can't reach about the last
foot. The top of the keel extends up so that the sole rests on it and
the hull is welded to the keel all around. My fear was that somehow I
would hole the keel and not be able to control the leak. I had thought
of pouring foam in but don't want to loose the storage space.

I sometimes use Great Stuff, sparyed into plastic shopping bags to
stabalize things, like my holding tank. Keep it firmly in place. The
problem with that is that it takes a while to set up. To long in time of
emergency. Ideally you would have some Great Stuff that would set up in
2 or 3 minutes. You could spray it into some kind of baggie and then,
once it is nearly hard, cram it over the opening, backed up by something
(cement or sole) and the foal would push into the opening.


In the 1500's to 1800's there was no such thing as a collision mat. As I
remember what I have read they took the extra sails and used them to close
the holes.



Not just then. One way to reduce the flow would be to get a sail over the
hole from the outside. That would definitely reduce the inflow.

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




Stephen Trapani March 15th 09 06:17 PM

New safety item
 
wrote:
One of the regulars on an email list I belong to just posted this:

************************************************** ********
The local coast guard came down to a boat which had hit a rock with a
can of foam-in-place. If you can slow the leak down somehow you can
fire that into the bilge or wherever and it will hold the water back
long enough for you to get somewhere. It is tenaciously gooey. I'm
planning on putting a can onboard.
************************************************** ********


I tell you, that expanding foam has no end of good uses. I use it for
many things around the house.

There was a bilge compartment on my H33 that was filled with water. The
damn compartment was inaccessible, but there was a small hole at the top
where the water got in. I got a can of expanding foam and sprayed it in.
The satisfaction of watching the water come pouring back up out of the
hole was immense. I had to watch out for keeping the hold patent because
if it sealed and the foam had nowhere to expand, bad things could
happen. I kept jamming a long screw driver into the hole to keep it
open. Water kept pouring up and out of the hole long after I finished
spraying in the foam. What a thrill that was. After the water quit
coming out I let it dry for a while then topped off the remaining hole
with a little caulk.

Stephen

Richard Casady March 15th 09 06:44 PM

New safety item
 
On Sat, 14 Mar 2009 16:11:54 +0000, Larry wrote:

no
firefighting equipment bigger than a 5# extinguisher. T


My daughter grabbed the 5 pound dry chem from the kitchen and went
after a grass fire that was already a good thousand square feet. Talk
about fighting out of one's weight. Big fireballs from ant nests. I
figure methane.

Casady

Richard Casady March 15th 09 06:51 PM

New safety item
 
On Sun, 15 Mar 2009 11:17:42 -0700, Stephen Trapani
wrote:

There was a bilge compartment on my H33 that was filled with water. The
damn compartment was inaccessible,


I wouldn't care much for inaccessable compartments below the
waterline. In a steel boat you can't deal with the rust. That product
sounds like a good thing to carry.

Casady

Wayne.B March 15th 09 07:13 PM

New safety item
 
On Sun, 15 Mar 2009 10:30:23 -0400, HPEER wrote:

Back to the foam. I have a steel boat and the aft half of my keel is
hollow and too deep for me to reach into. I can't reach about the last
foot. The top of the keel extends up so that the sole rests on it and
the hull is welded to the keel all around. My fear was that somehow I
would hole the keel and not be able to control the leak. I had thought
of pouring foam in but don't want to loose the storage space.


I think there's another issue with a steel boat. The foam will quite
likely trap moisture against the hull and promote rusting, invisible
rust at that. I wouldn't do it.


Vic Smith March 15th 09 07:22 PM

New safety item
 
On Sun, 15 Mar 2009 10:30:23 -0400, HPEER wrote:



Back to the foam. I have a steel boat and the aft half of my keel is
hollow and too deep for me to reach into. I can't reach about the last
foot. The top of the keel extends up so that the sole rests on it and
the hull is welded to the keel all around. My fear was that somehow I
would hole the keel and not be able to control the leak. I had thought
of pouring foam in but don't want to loose the storage space.

Most Navy ships have exposed hulls below the waterline, and carry
dunnage and purpose-made devices for bracing.
(I was a damage controlman for a bit, but by then it was called hull
technician.)
From what I've seen of sail boats, getting at a hole from the inside
might not be practical. You might get "lucky" and get holed in a good
place.
I'd look for a heavy plastic (visqueen-like) sheeting kit that can be
glued over the hole underwater. Might not be practical in cold water.
Since I don't have a boat I haven't looked for such a kit, but I see
no reason not to make one up.
Here's as far as I'll go in research
http://www.grainger.com/Grainger/ite...ements-_-1YDZ8
Just to confirm there are underwater glues readily available.
Might be a better one than this.
The kit should have a belt to keep it secure during the diving.
Maybe a couple different sizes of heavy plastic sheeting to cover
holes within reason.
Outline hole with this glue stick, slap on the sheeting, and maybe
razor off the excess sheeting beyond the glue outline.
Off course I'm not arguing against the internally applied foam.
The more prepared the better.
Stopping the water with the external patch will allow time to get at
it internally.
If I had water rushing in behind a fixed cabinet or other inaccessible
spot that the pump couldn't handle, my first inclination would be to
go over the side with the patch kit.

--Vic




HPEER March 16th 09 11:29 AM

New safety item
 
Wayne.B wrote:
On Sun, 15 Mar 2009 10:30:23 -0400, HPEER wrote:

Back to the foam. I have a steel boat and the aft half of my keel is
hollow and too deep for me to reach into. I can't reach about the last
foot. The top of the keel extends up so that the sole rests on it and
the hull is welded to the keel all around. My fear was that somehow I
would hole the keel and not be able to control the leak. I had thought
of pouring foam in but don't want to loose the storage space.


I think there's another issue with a steel boat. The foam will quite
likely trap moisture against the hull and promote rusting, invisible
rust at that. I wouldn't do it.


Actually most steel boats are insulated with foam above the water line.
This is the commercial variant of the foam not the minimially
expanding Great Stuff.

However you make a good point for the repairs and I would only do it as
an immediate expedient to stop a leak until I could address it properly.

HPEER March 16th 09 11:30 AM

New safety item
 
Vic Smith wrote:
On Sun, 15 Mar 2009 10:30:23 -0400, HPEER wrote:


Back to the foam. I have a steel boat and the aft half of my keel is
hollow and too deep for me to reach into. I can't reach about the last
foot. The top of the keel extends up so that the sole rests on it and
the hull is welded to the keel all around. My fear was that somehow I
would hole the keel and not be able to control the leak. I had thought
of pouring foam in but don't want to loose the storage space.

Most Navy ships have exposed hulls below the waterline, and carry
dunnage and purpose-made devices for bracing.
(I was a damage controlman for a bit, but by then it was called hull
technician.)
From what I've seen of sail boats, getting at a hole from the inside
might not be practical. You might get "lucky" and get holed in a good
place.
I'd look for a heavy plastic (visqueen-like) sheeting kit that can be
glued over the hole underwater. Might not be practical in cold water.
Since I don't have a boat I haven't looked for such a kit, but I see
no reason not to make one up.
Here's as far as I'll go in research
http://www.grainger.com/Grainger/ite...ements-_-1YDZ8
Just to confirm there are underwater glues readily available.
Might be a better one than this.
The kit should have a belt to keep it secure during the diving.
Maybe a couple different sizes of heavy plastic sheeting to cover
holes within reason.
Outline hole with this glue stick, slap on the sheeting, and maybe
razor off the excess sheeting beyond the glue outline.
Off course I'm not arguing against the internally applied foam.
The more prepared the better.
Stopping the water with the external patch will allow time to get at
it internally.
If I had water rushing in behind a fixed cabinet or other inaccessible
spot that the pump couldn't handle, my first inclination would be to
go over the side with the patch kit.

--Vic



This assumes you can get in the water. Where I sail the water temp is
in the high 50s, on a great day.

Larry March 16th 09 05:34 PM

New safety item
 
hpeer wrote in news:49be353d$0$19669
:

Actually most steel boats are insulated with foam above the water line.
This is the commercial variant of the foam not the minimially
expanding Great Stuff.

However you make a good point for the repairs and I would only do it as
an immediate expedient to stop a leak until I could address it properly.



Someone I know bought a used pickup truck that looked brand new.

It had a professionally-installed, sprayed-in plastic bedliner that was
really expensive in it.

The first time he got it in the shop, he helped himself to the bottom of it
while it was up on the rack at his fav garage.

Looking around for anything wrong, he was STUNNED to see the BOTTOM OF THE
BEDLINER in big holes of rust that used to be the truck's pickup bed!
Water had gotten between this bedliner sprayed on it and the steel, eating
away first the paint, then the hull....just like it would in a steel hulled
boat.

It looked great from the top, of course, as the plastic covered up the rust
holes and seems to support the load. Maybe Ford shoulda made the whole bed
out of plastic!


HPEER March 16th 09 07:53 PM

New safety item
 
Larry wrote:
hpeer wrote in news:49be353d$0$19669
:

Actually most steel boats are insulated with foam above the water line.
This is the commercial variant of the foam not the minimially
expanding Great Stuff.

However you make a good point for the repairs and I would only do it as
an immediate expedient to stop a leak until I could address it properly.



Someone I know bought a used pickup truck that looked brand new.

It had a professionally-installed, sprayed-in plastic bedliner that was
really expensive in it.

The first time he got it in the shop, he helped himself to the bottom of it
while it was up on the rack at his fav garage.

Looking around for anything wrong, he was STUNNED to see the BOTTOM OF THE
BEDLINER in big holes of rust that used to be the truck's pickup bed!
Water had gotten between this bedliner sprayed on it and the steel, eating
away first the paint, then the hull....just like it would in a steel hulled
boat.

It looked great from the top, of course, as the plastic covered up the rust
holes and seems to support the load. Maybe Ford shoulda made the whole bed
out of plastic!


Yeah, I think the foam works better than the bed liner. The foam is a
urethane and so is much of the marine paint. The bed liner appears to
be a polyethelyne or something but I'm not sure.

Marc Heusser[_2_] March 16th 09 10:46 PM

New safety item
 
In article ,
hpeer wrote:

Yeah, I think the foam works better than the bed liner. The foam is a
urethane and so is much of the marine paint.


Be careful - urethane may be acidic, and iron rusts in acids.
In a basic environment it is stable such as in cement/concrete.

HTH

Marc

--
remove bye and from mercial to get valid e-mail
http://www.heusser.com

Bruce In Bangkok March 17th 09 02:09 AM

New safety item
 
On Mon, 16 Mar 2009 17:34:53 +0000, Larry wrote:

hpeer wrote in news:49be353d$0$19669
:

Actually most steel boats are insulated with foam above the water line.
This is the commercial variant of the foam not the minimially
expanding Great Stuff.

However you make a good point for the repairs and I would only do it as
an immediate expedient to stop a leak until I could address it properly.



Someone I know bought a used pickup truck that looked brand new.

It had a professionally-installed, sprayed-in plastic bedliner that was
really expensive in it.

The first time he got it in the shop, he helped himself to the bottom of it
while it was up on the rack at his fav garage.

Looking around for anything wrong, he was STUNNED to see the BOTTOM OF THE
BEDLINER in big holes of rust that used to be the truck's pickup bed!
Water had gotten between this bedliner sprayed on it and the steel, eating
away first the paint, then the hull....just like it would in a steel hulled
boat.

It looked great from the top, of course, as the plastic covered up the rust
holes and seems to support the load. Maybe Ford shoulda made the whole bed
out of plastic!



In Thailand you can buy all stainless beds for the more common models
of pickup trucks. You frequently see them on trucks used in the
fishing or other food industry business. My B-in-L who owns a fairly
large noodle factory uses them on all of his company pickups. He tells
me that it you buy a new pickup and drive directly to the "body shop"
for replacement you can get the stainless body for less then US$ 1000.

Cheers,

Bruce
(bruceinbangkokatgmaildotcom)

Marty[_2_] March 17th 09 03:18 AM

New safety item
 
Marc Heusser wrote:
In article ,
hpeer wrote:

Yeah, I think the foam works better than the bed liner. The foam is a
urethane and so is much of the marine paint.


Be careful - urethane may be acidic, and iron rusts in acids.
In a basic environment it is stable such as in cement/concrete.


Say what? Best rethink that thought:
http://depts.washington.edu/matseed/...0Corrosion.htm


Cheers
Martin

IanM[_2_] March 17th 09 07:46 AM

New safety item
 
Marty wrote:
Marc Heusser wrote:
In article , hpeer
wrote:

Yeah, I think the foam works better than the bed liner. The foam
is a urethane and so is much of the marine paint.


Be careful - urethane may be acidic, and iron rusts in acids. In a
basic environment it is stable such as in cement/concrete.


Say what? Best rethink that thought:
http://depts.washington.edu/matseed/...0Corrosion.htm

Sorry but that link actually supports the original argument.
From the link:

When considering the initial state of the reinforcement in our
concrete bridges, we can state that the cement acts to protect the
reinforcement by passivating it. It forms a protective oxide coating
on the steel giving a pH of 13-14 adjacent to the steel. The
corrosion of the steel reinforcement occurs below pH 11. The pH of
seawater is about 8.



Yep, confirmed, stable in a sufficiently basic environment.
Of course, if you have voids or cracks next to the steel, eventually
chloride ions will get in there, the PH will drop, the reinforcement
rust and the structure will fail, but that's not a problem with steel in
a basic environment, its a problem maintaining a basic environment.

For a counter-example, examine *any* unprotected steel object exposed to
acid fumes or acid contact. Even the top of an old ketchup bottle . . .


--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & 32K emails -- NUL:

Martin Baxter March 17th 09 01:21 PM

New safety item
 
IanM wrote:



Yep, confirmed, stable in a sufficiently basic environment.
Of course, if you have voids or cracks next to the steel, eventually
chloride ions will get in there, the PH will drop, the reinforcement
rust and the structure will fail, but that's not a problem with steel in
a basic environment, its a problem maintaining a basic environment.


The devil is in the details.

We've a number of bridge problems, partial collapses, near failures on
many of the bridges and overpasses on the 401, (freeway connecting
Windsor to Montreal), seems the road salt was getting through the
concrete to the rebar. For ten years or so there has been an ongoing
project to replace the old bar, with new "green" rebar.

Cheers
Martin


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