I have been pretty busy on this project today, Went down the road to the Army Heritage Museum armed with a tape measure, note book and camera. It would have been great except my camera has decided that the battery will not hold a charge so no detail pics to post or use as reference. I also had some technical conversations with my dad and grand father, who both ran cable lift bulldozers.
This model is a bulldozer that functions with a cable lift of the blade. This is done with a winch usually located in the back of the dozer. The steel cable is run through a series of pulleys from front to back through sections of steel pipe, Not to protect the cable, but to protect the operator encase the cable breaks! Preventing the cable from whipping around and killing those that happen to be near it. This is a important detail and one the images above shows a mysterious pipe above the Right hand track that is now explained. I know from research that the Shervick bulldozers used the final drives, track brakes, clutches, transmission and diesel engine from Sherman tanks as well as the track components. After scaling my donor model, two real sherman tanks and my prototype images, I have decided that although the boogies form the sherman tank are used and the hull
might have been used in the prototype. I am going to scratch build the hull and super structure from evergreen and plastruct, using kit parts where applicable. This is because there is a difference in spacing between the boogies between the tank and what the images of the Shervick dozer show to allow space to mount the bulldozer blade between them.
I knew going in that I was going to have to use some license figuring out this conversion. Some of that modelers license is going to be in the cab and the winch, parts of the blade and parts that just are not clear form the reference available. One of the assumptions I am thinking about using is to use a "surplus" Braden/Tulsa PTO winch, these were used through WW2 right up to 1968 on Dodge Powerwagons, It would have been available in war torn europe and has the capability to lift the blade on a dozer. I also have access to one to measure, We (my father) has a 1967 Dodge MW300 Power wagon (guess what I learned to drive on), It was so fitted with a PTO winch of this type. My best guess is that this would sit in place of the driver and bow gunner/radio operator would be in the sherman tank on my dozer, I
know that there is a winch to lift the blade and that location makes the best guess as to its location.
In my conversations on early dozers, I learned a couple of other things that can apply to this model, First is a cable lift dozer's blade always floats, it relies on shear weight to apply force on the cutting edge of the blade, That is why the arms of the blade are so beefy in the images. I also learned that
usual practice in controls are as follows. In addition to the PTO and Winch controls I will need steering yokes, control left and right tracks though brakes and clutches, Gear shift and clutch petal and a
decelerator petal, it seems that early dozer engine ran at governed speed unless the engine was decelerated with application of the pedal usually to change gears, opposite of what a car or truck would be. Now I have no idea whether or not the Shervick tractor/dozer used these controls or what the exact lay out is but building my model around common practice makes a sort of back handed sense.
Below is my progress on the hull and track assembly, I need to make decisions on the tracks soon, use either the kit parts, another kit parts or some fancy ModelKasten or Verlinden "workable" tracks which would add expense to this project but make getting the lengths a little easier and probably sag more realistically. I need to start mocking up the engine and cab then I can figure out the engine overhang on the front of my hull. But not a bad start on this project. I also found out that the one remaining Shervick tractor in Belgium (the image in color) was scrapped in August 2008, Swords to plows to razor blades.
