I am modifying my MkI model to make the MkII and MkIII. I made the following changes:
deleted the round top hatch
added the wedge-shaped top hatch from my MkIV. (Question - are there any good top views of this to show how it is located with respect to the hull centerline? In a view of the Bovi vehicle this hatch seems to slightly overlap the centerline. I have it offset further to starboard right now, but I can easily move it.)
deleted the tailwheel assembly. (Question - what did the rear face of the hull look like, where the hydraulic system had been on the MkI? Were all traces of the hydraulic system gone completely? I left some the brackets and other bits for now)
(Question - was the MkI's bow pistol port deleted on the MkII and MkIII?)
made the cab narrower. I used the drawing of the cab front development as a guide - I am attaching a shot of my interpretation of that drawing.
made the cut-outs for the idler adjustment screw more squared off.
the MkII female will retain the MkI sponson; the MkIII will use the MkIV female sponson with a couple of small changes.
Helen's photos show that the hatch did encroach upon the centre of the roof.
As for the port in the front of the cab, there is a thread on the subject of such changes - I'll see if I can find it. Someone, I think it was Mark Hansen, posted illustrations of the differences.
Is this hole a pistol port? I see 4 holes in a diamond pattern around the hole. The remaining bolt is larger than those on the other pistol port covers, and the scrap of steel still attached to that bolt looks different (thicker) from the surviving covers.
Based on Helen's photos, I also had to make the wedge-hatch narrower than the one I made for the MkIV (screen shot of parts is also attached)
I am still in two minds about this port. I think it could be a rear periscope position, as the bolt pattern matches the ones on the cab roof. The bolt and bit of metal plate may not be original, looks more like a later alteration or repair.
If it is not a periscope position, then it could be a pistol port of the kind on the lower cab front, with an internal shield.
Right better get moving as I'm going to the Overlord Show at Denmead today... and the weather is good! YES!!!
I can believe a periscope port like the two on the cab roof - a pistol port pointing straight uo would seem to have limited use. The bolt/rivet patterns do look the same. Hmmm... maybe the 4 small holes were for an internal bracket to hold the periscope in place when in use? If that is the case, there should be two bolts for the rotating cover, unless they were internal like the bow pistol port. I take it from your drawings that the ones on the cab roof do not now have covers. Some, but not all, drawings of the MkI-MkIV cab roofs show external covers shaped like the pistolport covers; I have learned to take those drawings with a large grain of salt. I will scour the photo records for some indication of external covers.
Re: pistol ports vs periscope ports - a photo on page 44 of the Osprey MkI book shows two open holes on the cab roof and another left of the wedge-shaped top hatch. The photo is grainy, but there seems to be no sign of external covers on any of these holes. Unfortunately, there don't seem to be covers on the three pistol ports on the cab rear face, either, so maybe they were all removed.
Another question: does anyone have photos of the storage boxes added onto the lower rear face on MkII and MkIII tanks? Were these standard, or improvised?
Re: pistol ports and periscopes. The problem about this feature is as you observe. All I can say is that it corresponds with that of the Mk IV, in a position which surprised me, as it would be partially obstructed by the exhaust system. If it was a design feature from the tanks without that type of exhaust, it appears slightly more useful, if still quite strange. On the Lincoln Mk IV there is a complete, intact cover as for the other pistol ports, but there is no way of knowing if that is original or a later addition.
Once you start looking for something at that location on early photographs it seems to be there. And I expect it would have greater value for a periscope...
Confusing, certainly.
-- Edited by Michael Taylor on Thursday 6th of June 2013 04:20:03 PM
Did you ever get an answer to the storage box question? Unfortunately not something I know the answer to. I expect they were both, starting as a field change that later becomes standard fit. I know that before the tail wheels were removed from the MK1s that they started fitting storage boxes to them, so maybe this extra storage was missed by the crew.
I presume you've looked at the Landships.info page on Mks I-III tanks? There is a grainy image of a Mk II showing the box in the background of another tank, and a closer image as a still in the video PDA put together. You won't get an exact idea from these, but the boxes seem simple enough.
I finally found a pretty good photo of the rear box. Tankograd 1003 "Beute-Tanks, Vol 1", page 10, middle photo shows the rear of MkII female D28 No586, including the box.
Also found some photos of the periscope covers on MkIV's - same book, page 92 shows views of the top of Lodestar III (Brussels). All three periscope ports have rotating covers that look to be the same as those on the pistol ports. I don't know if it is significant, but the bolts, rivets or other protrusions are not in a diamond pattern like those on the MkI cab roof.
Wayne: the Tankograd photographs of Lodestar are the very ones that I was going to refer to concerning the periscope apertures and covers. The ones which are open, on top of the cab, seem to me to allow the small diameter of the periscope to fit, and perhaps be retained in position by something fairly simple, in the recess around the aperture. adjacent to the hatch is the feature also observed on the Lincoln tank. This is closed, but has the same arrangement of hexagonal bolt heads around it as the periscope apertures. Pistol ports do not seem to have so many.
This makes me come to the tentative opinion that this is an auxiliary periscope aperture, possibly without any means of retaining the periscope in position, as it would be less frequently in use than those on the cab. There appears to be evidence of a similar feature on photographs of MkII, MkIII as well as those to be found on the MkIV.
The Lincoln MkIV has been exposed to the elements at some time, and I did not feel that my access to the top of the tank allowed me to take liberties with the ports and covers. (I did make notes of measurements in order to prepare drawings, and used film cameras for the last time, and I have not been back there yet to make further notes.)
The photograph of the Mk II shows the configuration you note. The remnant of the "cover" does not seem typical. I just hope that more photographs from the first deployment of the Mk II appear, and show more clearly whether this is a feature of the tanks as constructed, or a modification.
Ok now I know someone's going to say they can't see it.... but in this classic photo there is a black tube protruding up out of the roof in exactly the right place. Now I'm not saying it's a periscope for sure, it is thicker than the cab ones.... but other than a vent, I can't think what else it could be?!?! :)
I can see what you're referring to Helen, and it may be a periscope. It does look a bit shorter, perhaps also thicker - although the thickness may be a case of trompe l'oeuil with track treads and a tarpaulin nearby to confuse things.
It occurs to me that it could be useful for the Mk 1 to have a periscope in the roof, because the raised manhole with it's ports was not present; only the driver and commander/brakesman would be able to see on top of the tank using the cab periscopes, so it makes sense to provide one further back for crew members not directly engaged in driving the tank.
Such a feature would of course still be there on a Mk II - although for Mk IVs there is a question mark.
Drawing 22097, (Hull details-interior, MkIV machines), shows the periscope apertures of the cab and the four additional holes drilled for the bolts associated with the covers and stops. The same configuration appears in the roof adjacent to the hatch, marked "In Top on This Side", and the diameter of the aperture appears to be the same as for the periscopes. This looks to me to be very similar to details captured in photographs of MkIIs, MkIIIs, and on Lodestar and Flirt II. I am certainly prepared to believe that it may also be found on the MkI. Incidentally, the same drawing also shows the bow port as 4" diameter "Hole this side only". (The drawings appear as the end papers of a recent book which I would hesitate to commend to anyone for a number of reasons.)
Here are some photos of the completed MkII female C21 "The Perfect Lady". The name in small black letters on the khaki background barely shows up at all. I left the 3-digit number off the lower rear side frames 'cause I couldn't find any photos that showed it.
The track extensions are a bit tedious to make, but I think they add a lot to the model.
Looking good Wayne! I like the contrast the early camouflaged sponsons give.
I missed Bovi today due to my Dad needing looking after, but on the plus side I may get to visit next week some time and get some female sponson measurements.