Landships II

Well, I have spent three hours this evening poring over dozens of books and many hundreds of images on my computer with little joy. There are images where a tank has been hit in the cabin, blowing it apart leaving the tracked sides laying flat on the ground, but never from an angle that allows you to see the area I am interested in. There are photos of tanks climbing obstacles exposing the underside, but it is always in deep shadow. There are several photos of the underside of a tank laying on its side, but again the viewpoint does not expose the area of interest.
One photo that may provide evidence is on page 12 pf David Fletcher's British Mark IV Tank, showing a tank under construction at Hurst Nelson, but the shadow area is not very clear - does anyone have a better quality print of the image that may show the holes?
If anyone is going to Bovington in the near future would you possibly be willing to get down on your hands and knees and take some photos for me showing this area from both the front and rear of the tank.
Thanks for all of the help so far
Andrew

-- Edited by MehdiT on Saturday 16th of February 2013 05:03:22 AM

TinCanTadpole wrote:

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I'll need to look to see if any photos show such holes, but even if they don't, it does not mean that they did not appear on tanks: similar holes can be seen on the outer track frames of some Mk IXs - but not all; it seems quite possible to me that some tanks may have featured these holes and others not, perhaps depending on manufacturer and production batch.

Re Charlie's comments, I think he is mistaken - these holes are not inside the hull, but just underneath the floor level, open to the atmosphere. The floor of the tank is indicated by the thicker line just above the holes, encroaching upon the edges of some and turning at one end up for the frontal plates and at the other for the vertical rear bulkhead.

The idea of inspection holes seems plausible to me, as these holes would tend to let mud and water in as well as out - compounding any problem in this area. Drain holes thus seem less likely. Whatever their purpose, if they only featured on some tanks (which has yet to be determined), it may be because they would make mud-clogging problems worse.

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 That's why I referenced the images of surviving Mark IVs - the attached is from Landships II - Flirt II. You can see the lower hull plates are close to the rails for

the U-bolts. Comparing this to the drawing the large holes would be inside the hull under the floor plates.

Charlie

 

I see what you're suggesting, Charlie, but that gap only applies for the frontal plates; the ground clearance for the belly plates is larger, by about half.

Look again at the plan/panels pic posted by Mehdi T - the floor of the tank is the darker line right above the circles, overlapped by the red circles, which are more below the line than above.

There are some small reference letters marked on the plans, in small circles; near the lower edge of the front lower curve of the track frame is one which says 'Y'. Look a little further to the left of this, there is another which says 'X'. This 'X' is right below the dark line that marks the floor level, just a bit to the left of the kink between the lower frontal plate (as pictured in your photo of Flirt II) and the floor plates themselves.

I don't think they are covered by a plate: I think they may only have featured on certain tanks. That said, this photo from SVSM, as pointed out by Basilisk, appears to show two or three holes well underneath the APG MkIV - just below the tightly-packed line of bolts on the belly, to the right of centre:

http://svsm.org/gallery/mkIV/IMG_3654

Edit: This on the inside of the left track frame, looking forward; a corresponding photo on the site for the right-hand side does not show any holes.

-- Edited by TinCanTadpole on Saturday 16th of February 2013 04:42:55 PM

Andrew, look along the 'L' rail, well underneath the floor of the tank in that photo you just posted: you will see plenty of rust just above the rail, with a patch of intact faded green paint (at the same level as your "hull floor" tag). Look to the right of the faded-paint patch, onto the rusty plating which sits below the position of the sponson, above the track-contact patch; there is a mass of bolts hanging on the underside of the tank at this spot - look immediately below these bolts, I think you will see two of the holes (narrowed by perspective, so they look closer to slits) marked on the plans just below where the post-it is on your original photo. I think it is one of the 'twinned' holes plus the single hole to the left of them.

The SVSM site is interesting, but I think it disappointing that amongst the tank walk-arounds there isn't one for the American M1922 Medium A that used to be at APG; I think it's the only surviving tank with Philip Johnson's wire rope suspension and articulated track.

-- Edited by TinCanTadpole on Saturday 16th of February 2013 05:43:05 PM

Basilik, I think I understand what you meant by an 'L' shaped plate now - I think I can see an extra layer of metal between the two 'U' bolts either side of the circle I drew - it looks like the nut on one side of each 'U' bold sits higher. I think this is a flanged cover that is held in place by two nuts, one from each of the adjacent 'U' bolts (if you look at the drawing in my first post each hole is directly inbetween a pair of rollers). The cover seems to be crudely shaped because if you look at the nut at the top left of the circle I drew on the photo (third away from the rear hull plate), I think I can see part of the circular hole it is covering. Boy a high-res photo and some tweeking in photoshop would be useful.
Thanks again for all of the replies. I think my course of action at this point will be to go ahead and drill the holes, I then need to figure out if all or just some will need cover plates.

Good thread, yet again it seems I have missed something when drawing out my plans. 

I think inspection holes is right thing to call them. Oiling being done through the axles of the rollers. They have been there since day one, as the MK1 and Bovi's MK2 also has them.

Another update to add to the plans. But it makes them that little bit more accurate, so I'm happy. :)

 

 

Andrew, it sounds like you've got it now. Sorry, rereading what I wrote earlier I realise I should have been a bit clearer.

I'd draw you attention to something you may have overlooked:
http://landships.activeboard.com/t8735856/awm-mk-iv/
photos 24 and 25 shows light from the flash highlighting the edges of plates above the U-bolt anchor angle iron but not below. Also if you look at your first post there are rectangles that would seem to correspond with both the holes and cover plates (except for the rearmost one which has a more tombstone look to it), possibly you've had the answer all along?

 

Ok - the case seems pretty solid that the 5" holes in the inner plate were covered by thin plates which were bolted to the U-bolt frame.

Examples where the holes are visible on surviving tanks seem to be due to the cover plates rusting away. 

So what were the holes for? I can't see them as inspection holes because they are pretty inaccesible unless the tank is jacked up -

any hypotheses about the function of the holes?

Regards,

Charlie

Not necessarily - the Mark V is approximately 50 cm ground clearance .... No major problems, you can unscrew the screws there - oiled ...........The Mark IV is the same I think ...
Andy