There's that navy humidity reasoning again

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JK
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There's that navy humidity reasoning again

Postby JK » Sat Nov 04, 2017 9:29 am

http://thechronicleherald.ca/novascotia ... -warships#

What a crock.
I'll bet they have had numerous downflooding incidents. It gets under the subflooring and goes all though that deck and lays against the steel for years. I wonder what their deck camber is. The water would lay against the hull if it is of any significance.
I wonder exactly how much steel they replace other then ribs :shock: So many questions in my curious engineering mind.



The rust problem is linked to mould reportedly discovered in all of Canada’s frigates, said Ken Hansen, a military analyst and retired naval commander living in Dartmouth.

“Humidity in the ships is too high,” Hansen said. “I know they’re looking for a good solution to the problem.”

The hull of warships is typically cold because of the outside ocean temperature, he said.

Warm, moist air caused by more than 200 sailors living inside a ship, as well as heat from the engines and electronics, condenses when it hits the cold steel, Hansen said.

“All that heat carries moisture. So unless you can do something about that moisture through your dehumidifying system, it’s just going to get worse,” Hansen said.

The air inside warships is 90 per cent recirculated, he said. “They only take in a little bit of air from the outside, and the rest is continually being recirculated by these air conditioning and ventilation systems.”

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Merlyn
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Re: There's that navy humidity reasoning again

Postby Merlyn » Sat Nov 04, 2017 11:48 pm

S.S.S.
Sweaty Sailor Syndrome ( or shit metal )
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Big Pete
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Re: There's that navy humidity reasoning again

Postby Big Pete » Sun Nov 05, 2017 1:52 am

Problems, problems, if they believe inadequate air con is to blame and they want to run the ships longer, why don't they just fix the air con?

Mad World, Military procurement. I have just read the article (link below) about the Royal Navy cannibalising spares from one ship to another and how it actually costs much more than buying new parts. I assume that if a ship in service breaks anything they dismantle the parts from a ship undergoing repair or laid up and ship it out to the operational ship, and when the cannibalised ship is brought back into service they take all the parts required off the next ship to go into Dry Dock. Penny wise, pound foolish as we used to say over here.

https://www.imarest.org/themarineprofes ... -for-fleet

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Last edited by Big Pete on Sat Nov 11, 2017 6:36 am, edited 1 time in total.
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D Winsor
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Re: There's that navy humidity reasoning again

Postby D Winsor » Sun Nov 05, 2017 4:37 am

Big Pete wrote:Problems, problems, if the believe inadequate air con is too blame and they want to run the ships longer, why don't they just fix the air con?

Mad World, Military procurement. I have just read the article (link below) about the Royal Navy cannibalising spares from one ship to another and how it actually costs much more than buying new parts. I assume that if a ship in service breaks anything they dismantle the parts from a ship undergoing repair or laid up and ship it out to the operational ship, and when the cannibalised ship is brought back into service they take all the parts required off the next ship to go into Dry Dock. Penny wise, pound foolish as we used to say over here.

https://www.imarest.org/themarineprofes ... -for-fleet

BP


That's what you get when you let the show be run by accountants and political types. They are quick to point out the money the saved on "New" parts procurement and conviently ignore the time and labour costs needed to salvage, refirbish and prematurly replace "Used but still good" parts as these costs are due to budget mismanagement by others.

A few years ago I was approached by my manager and told how the purchasing department had landed a great deal on a supply of "High Quality" engine spares on the internet. When I received the parts it was obvious the parts were well used, worn past the tolerences and were only good to be sent to the scrap bin. Later after telling my manager what I intended to do with the parts and learning the price paid for the individual parts. I suggested that he tell the Purchasing Manager that with his "Great Deal" the Company paid $350.00 a pound for scrap brass. :oops:
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Merlyn
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Re: There's that navy humidity reasoning again

Postby Merlyn » Sun Nov 05, 2017 1:51 pm

Never met an accountant or politician who knew anything whatsoever about engineering.
They couldn't fit a match in a matchbox never mind fitting engineering components.
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Re: There's that navy humidity reasoning again

Postby JollyJack » Sun Nov 05, 2017 3:12 pm

Never been on a warship, obviously.

"The hull of warships is typically cold because of the outside ocean temperature, he said."

There is a substantial layer of insulation on the hull, at least there was when I did trials on them. The interior of the ships is climate controlled, temperature and humidity are closely monitored and adjusted.

"Ken Hansen, a military analyst and retired naval commander living in Dartmouth." There, says it all, a Rupert.
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Big Pete
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Re: There's that navy humidity reasoning again

Postby Big Pete » Mon Nov 06, 2017 1:25 am

If you were building a house you would have a vapour barrier between the cold hull and the warm inside of the ship to prevent humid air getting through permeable insulating material and the water vapour condensing on the inside of the hull. One way would be to coal Tar epoxy paint and then spray foam it, problems being that you could no longer make an internal inspection of the steelwork and that although spray foams can be be made "Fire Resistant" or "Fire Retardant" none can actually be made Fire Proof and when they do catch fire they can generate more and more Toxic fumes than ordinary foam. There must be a solution out there.
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Merlyn
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Re: There's that navy humidity reasoning again

Postby Merlyn » Mon Nov 06, 2017 9:03 am

In 1960 the ships sides / bulkheads were painted with black pitch ( which was also used on the inside of big circulating pumps for steam engine condensers ) in which was mixed loads of chopped up cork fragments.
Not strirring it enough would result in the cork settling in the tin bottom and loads of condensation streaming down the sides of your cabin.
You could lie in your bunk and watch the rivulets running down.
Fascinating.
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Big Pete
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Re: There's that navy humidity reasoning again

Postby Big Pete » Mon Nov 06, 2017 11:56 am

Digressing a bit, I remember reading that Lt Commander Neville Shute Norway RNVR ( Better known as the author, Neville Shute) who was an aircraft designer in his day job, during the war worked in a Department doing Scientific Research for the Government, investigating all sorts of oddities and designing gadgets for SOE and equipping airmen flying over hostile territory with gadgets to help them evade and escape the enemy.
They were involved in investigating reports from Merchant ships, after Dunkirk, that bullets that had gone through their Decks appeared to have been deflected by Cork insulating Granules in the Deckhead paint. That lead to the development of "Plastic Armour" Granite Chips in Bitumen which proved to be lighter and cheaper than steel armour plating and much more effective than concrete (as well as not being a scarce resource in Wartime) and was widely used to armour plate fighter planes seat backs and the Bridge Wings of Merchant Ships.
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Merlyn
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Re: There's that navy humidity reasoning again

Postby Merlyn » Mon Nov 06, 2017 12:45 pm

Help the cause, drink more wine.
Be a major cork donator.
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JK
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Re: There's that navy humidity reasoning again

Postby JK » Thu Nov 09, 2017 6:23 am

"Ken Hansen, a military analyst and retired naval commander living in Dartmouth."

Exactly what I thought. Talking out of his ass.

Spares! LOL
We were so cash strapped that we used to take equipment off one ship and give it to another. We had one of the fellows store every old piece of equipment in our warehouse. When he left, it all went for scrap.

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Merlyn
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Re: There's that navy humidity reasoning again

Postby Merlyn » Fri Nov 10, 2017 1:02 am

Him too?
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Big Pete
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Re: There's that navy humidity reasoning again

Postby Big Pete » Sat Nov 11, 2017 7:10 am

"The hull of warships is typically cold because of the outside ocean temperature, he said."

There is a substantial layer of insulation on the hull, at least there was when I did trials on them. The interior of the ships is climate controlled, temperature and humidity are closely monitored and adjusted.


I agree with everything the Naval Officer said above, but if the hull is insulated with a porous material, such as Mineral Wool, Rock Wool or Glass Fibre, Hot Air with a High Absolute Humidity, will filter through the insulation and come in direct contact with the Cold steel Hull of the ship, where it will be cooled below its Dew Point and condensation will form on the inside of the Hull leading to corrosion, mould and all the other problems reported. There has to be a vapour barrier fitted between the heated inside of the ship and the cold hull to prevent this.
I remember once going on a family Holiday to the Theme Parks in Florida with another family and we rentd a House for the stay. After a few days the AC was struggling in the main family room and our friends daughter said she could hear water noises from the A/C outlet, so I took the grill off and found that the Duct ran under the floor then up the wall to the outlet grill and the bottom of the duct was full of water, the air pressure would build up and force the water level down and allow some air through and then as the air pressure dropped the water level would come up and block the air flow until the pressure built up again. I bailed out all the water which got the A/C working again and went in search of the source of the water. Found the A/C unit in the garage and the condensate drain was blocked, and all the condensate was going through the air trunking. The water drain ran vertically down the outside of the A/C unit across the floor, through into the house into the kitchen up to join the kitchen waste pipe. About a 6 inch drop in a twenty foot run of small bore pipe, which was all clogged up with mould, bacteria etc, so I just disconnected it in the garage and let the water run out the garage door. Solved the problem, but the same thing can happen on ships if the drain pipework isn't properly designed, installed and maintained.
A lot of things can go wrong with air conditioning, especially if people who don't understand how and why it works start tinkering with it.
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Merlyn
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Re: There's that navy humidity reasoning again

Postby Merlyn » Sat Nov 11, 2017 8:33 am

Working holiday eh BP?
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Big Pete
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Re: There's that navy humidity reasoning again

Postby Big Pete » Sun Nov 12, 2017 6:57 am

The thinking man never stops thinking, and the analysing man never stops analysing, and it was getting hot and humid....
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