Chris,
The Haynes book on the Mark IV has some fair shots of photos of the fascine. As stated in a previous post, you can also find some great photos on line. I wish I could post photos on the site, I'd show you how I did it. Basically, the fascines were cut in France from saplings, there was a wooden beam placed against the bottom of the fascine, and two chains went completely around the bundle to keep it together, the wooden beam then laid across the ditching rails. The chains around the fascine were placed at the 1/3 points of the bundle. Two more chains came from the front mid point of the bundle to wire hooks which attached to inverted "J" shaped hangers mounted at the junction of front hull plates. At the back of the fascine, two chains came off the mid point of the bundle, down into a "V" shape, to an iron bar fulcrum latch protruding up through the hull at the rear of the drivers copula. When the commander pushed the bar to the rear, tension was released on the rear "V" shaped chain, and the fascine rolled forward off the tank and (hopefully) into the trench. the open "J" shaped inverted hangers allowed the chain to drop free of the tank. If you want to build a fascine, I recommend using broom straws from a natural straw broom (redundant, I know). they give the most realistic appearance. VR, Russ