Are the vents in the rear parcel shelf to ventilate the boot from the cabin or the other way round ?
Also should the roof of the boot be lined as mine isn't. although the rest of the boot is.?

 

Yes, the inner top of the boot should be lined with "carpet" like the rest.
I would have to guess about the parcel self vents and I would say that the idea is that overpressure (when the windows are open) from the cabin can dissipate thru those vents, while the boot itself should also have vents on the sides to let the air-pressure out. I know the S-Type has those side-vents behind the side carpets and I can only guess that the X-Type has them as well.

 

Blues boy, if I am remembering the X-TYpe correctly, there are vents that go from the interior of the car to the outside in the wings of the boot. These are there to equalize the pressure between the inside of the car and the outside. The vents are in the rear shelf to help move the air from the passenger cabin, into the trunk to be relieved. When you shut a door, a large amount of air gets trapped inside the car and if it wasn't for these vents, you could in theory pop out a window. If you want to see this happen, simply get out of the car and shut the door quickly (don't slam it so hard as to cause damage, but give it a nice push shut). As you are shutting the door, watch the other door on that side, specifically the window. You will see the reflection in the window bounce all around as that is the glass flexing and the other door being pushed out because of the air pressure. It isn't so much the shaking of the car from the door shutting. This is also why if you get a new windshield put in, they tell you to leave a window down and to close the doors gently. This minimizes the amount of air that gets pushed into the car and gets trapped,

 

So I was nearly right. Pressure is the answer. But Thermo is right, it would be mainly for when you shut the doors.
I was only thinking about the interior pressure buildup, when you open the windows while driving fast.
Also, when the the sun heats up the interior, the air-pressure inside would also build up, if it were not for those vents, but I do not know, how significant that thermic pressure buildup would be.
Funny that Thermo did not mention the thermic effect...

 

Peter, I didn't mention it for 2 reasons. The bigger one being that no car is air tight, so, as you slowly build up any potential pressure, it would leak out various joints like the air con intake and around the door seals. The second reason is the simple physics of how air pressure works. To calculate how much pressure would change, you use a simple formula, Pressure / Temperature (since the volume is going to be constant. So, you have to look at both pressure and temperature in absolute values. So, air pressure is going to be 14.7 psia (0 psig + 14.7 psi for the difference between absolute and gauge pressure). Next you have to look at absolute temperature. I am going to use farenheit to start with, but that in absolute would be the temperature plus 460 degrees (to get rankine temperature). So, lets assume the initial temperature is 70F on a normal day (no big pressure things going on). You can solve for the temperature needed to get say a 1 psi addition to the interior of the car (assumine it was perfectly sealed by going 14.7 psig / 530 R (460 degrees plus 70F) = 15.7 psia (the initial 14.7 psia plus the added 1 psi) / X (where X is the needed temp to reach that point).. So, doing a bit of math, the temperature needed would be 566R, or 106F.

You can get much more pressure by simply having the door act like a fan and pushing air into the car. Not sure how much, but I know it is enough to make the doors flex if you are moving the doors at even a moderate speed.

 

Thermo, sounds like you really do know a thing or two about Thermodynamics. I guess you are working somewhere along those lines.

 

Or, Pete, he is just saying you are a bit of an over thinker....

 

I just told my wife about this thread with the parcel-shelf... - she immediately asked with bright eyes: I have a parcel shelf in my car?
I know, what she meant: She receives a lot of parcels - and now she learns that there is a parcel-shelf in her car...

She did not know the English term for it, as it is a "Hutablage" in German, which is a place where to put your hat...
Btw.: My mother was always on about those guy, who are wearing a hat WHILE driving:
Those are the guys, who just cannot drive, she said. That was about 1975 in Germany and she had a valid point there...

And the reason as to why my first thought - as to why the vents are there - was the air-pressure buildup inside of the car, while driving fast with open windows, was that this was a bit of a problem with my VW Polo back then in Germany: That was quite an uneasy feeling with the windows open while driving fast (kind of like being in a pressure-chamber with increase pressure), as I do not think that there were vents in the rear of the Polo:
Yes, a Polo can drive fast - my red 1986 Polo Fox has a total of 45PS (=44.4hp) and downhill on the Autobahn I managed to get it up to 170km/h with everything shaking and rattling, esp. the steering wheel, sometimes overtaking something like a Porsche... That was fun!

And this Polo had already 6PS more than our Polo, which we had before that, which I totaled in Italy to no fault of my own, when someone crashed on a deep snow covered road into my Polo pushing me off the road and down the side. Thinking back, I had the black contour of a black panther on that white Polo... - probably a herald of things to come... - i.e. my Jag-collection...

These 170km/h are way faster than I will ever be able to drive any of my high-powered Jags due to the utterly ridiculous general speed-limit of 110km/h in NSW/Australia and surrounding states.

 

Peter/Yorta2, my work revolves around understanding thermodynamics and pressure changes. I started off life having to understand all the ins and outs of how a nuclear reactor works and how pressures and temperatures affect things (on both a physical level and a structural level). Now I am working as an instrument tech on a nuclear reactor where I am calibrating all these instruments to measure these parameters. So, 35 years of being around nuclear power, I have learned a thing or two. I just take that knowledge and apply it to cars. Scary what you can come up with some times. Toss in a general interest in learning new stuff, amazing what you can learn about in a day.

On a side note, you have heard the term "can't hit the broad side of a barn!". There is a reason why you can't. A barn is an actual unit of measure. Look it up. When you find out how big it is, it will explain why no one can hit the broad side of a barn.

 

Peter,

Are you sure about the carpeting under the parcel shelf roof part of the boot ,as somebody on another forum says there's doesn't have any either.Was wondering if someone has removed mine to access the rear speakers and not put it back,in which case I don't know if it's worth the hassle of trying to purchase a replacement as I haven't seen any for sale and you can only see the area if you have your head in the boot lying on your back !

 

Blues, you original question was:
> Also should the roof of the boot be lined as mine isn't.

While it is a funny way to describe anything as "the roof of the boot", I concluded that you are asking, if the underside of the boot-lid is carpet-lined, which it is.

Now you are asking, if there is "carpeting under the parcel shelf". No it is not, because, as you correctly state, this "you can only see ..., if you have your head in the boot lying on your back", and Jaguar did not spent this extra kind of money on the X-Type for people, who get abducted by the Mafia in the boot of the Jag, so that they, too, would get the full Jaguar experience, because the X-Type was always supposed to be the low-cost version of Jaguar, so that people, who would normally not be able to afford a Jaguar, could afford one now. But as we all know now, this idea backfired, because the people, who would normally buy a Jaguar did not like that idea at all.

For the people, who get abducted in boots to also get the full Jaguar experience, the S-Type is a must have, which is from the same era, but more expensive: I just checked: This one has the carpet under the parcel shelf.

 

Right then Peter,note to self.I best make sure to get an S type and some Ray Bans before resuming my Mafia activities.

 

Thermo.
I assume your occupation throws some light on where your user name comes from.

 

Blues boy, yes it does. IT is actually short for Thermomonkey and there is a story behind the name. Being an enlisted guy running a nuclear reactor with 2 other enlisted guys and 1 officer, you develop a small family. Well, the officer said that we were nothing more than trained monkeys because we see a light come on, do a set of canned actions and then report (true statement, but that is besides the point, LMAO). So, we gave all the enlisted guys in our section a monkey name. Since I control the termperature of the reactor, I got the name "Thermostatic Monkey" (which I have shortened to Thermomonkey). But, we had power monkey, tron monkey (electron monkey, the guy controlling the electrical grid of the sub), turbine monkey, water monkey, oil monkey, etc. We had a good time with the names. BUt, the enlisted figured that the officer was a monkey to because he is doing nothing other than making sure the other monkeys do something. So, we created a name for him, Worthless Monkey. We figured it fit him perfect as he does nothing. The officer did not find it funny which made the enlisted laugh that much harder.

20 years of living on a submarine. Lets you see things that you can only imagine of.

 

...and after all that you do not drive a yellow Jag... (This is a Beatles reference... )

And when you wrote above that a temperature increase from 70 to 530 Fahrenheit would lead to an increase from 14.7 to 15.7 psia, I knew that you are or were working with Thermodynamics on a professional level. I knew that the average air-pressure at sea level is about 1 bar, which is about 14.5 psi (the pressure depends always on the weather of course - like high and low pressure, as every pilot (who has not crashed yet) would know), but your calculation was one level above of what I knew, plus I have not used psia (psi absolute) yet either....

 

Thermo:
There is actually something I am wondering about after having seen several U-Boot movies:
Are there outside cameras and/or underwater-periscopes these days?
I know that the standard periscope cannot be used underwater, if you don't like water in your U-Boot, but why not adding a permanent optical "window" in shape of a second periscope to be able to see the surrounds?
And at the time of U96 having an outside video-camera would not have been in the cards - but these days?
I can't find clear answers via google.

 

You certainly don't want water in your boots.

 

It's not a typo - and I noticed, when I wrote it, that it could be read as "boots", but I can't help it that this is the correct German spelling: A boat is in German a Boot.
A U-Boot is an Untersee-Boot, an under-sea-boat. Funny that you only have to change 1 letter each in any of those 3 words to translate it...

 

Peter, who says you cannot use a periscope underwater? The periscope is sealed, but can move up and down. So, I can raise it at any depth. Now, how far you can see, that is a different story and that really depends on the water that you are in. I can tell you from experience that a periscope can be used underwater as we used to put ours on a network in the sub so you could see on the mess decks what the person on the periscope was seeing. There was one time I walked onto the mess decks and noticed that we were right behind another sub and we were looking at their screw (propeller). I counted the blades and quickly realized it was not one of ours. That is when I got a bunch of stupid looks at me, then a bunch of people putting their fingers to their mouths to say "shut the @#$% up". Oh the days of playing games with "Country Orange" (military talk for whoever is playing the bad guys that week).

As for why no camera on the outside of the sub? Simple, being able to see more than about 50 feet underwater can only be done just below the surface of the water and only in limited places. You get around say San Diego or Seattle, the water is very murky and you can only see about 10 feet in front of you. Not very useful. Even in pristine waters like the Caribbean and that around Hawaii, you are limited to around 200 feet or so. Not very useful in most situations.

 

OK, makes sense, and I kind of thought that much, but I was also thinking of a certain scene in a movie, when I asked the question above:
I thought, that a bit of visual would have helped in the narrow "Secret Passage" in the Movie "Hunter Killer" from 2018, but they did not hint in that movie that they have any visual reference other than sonar.