diff --git a/microcar/tub.scad b/microcar/tub.scad
new file mode 100644
index 0000000..ce18b4e
--- /dev/null
+++ b/microcar/tub.scad
@@ -0,0 +1,96 @@
+$fn = $preview ? 32 : 256;
+
+a_pillar_y = -400;  // y location of face of 'A' pillar
+bb_height = 274;    // internal height of battery box
+bb_width = 260;     // internal width of battery box
+
+/*****************************************************
+ * the 'cowl' is the near-horizontal panel which the
+ * bottom of the windscreen is mounted to. In practice
+ * this probably slopes down forward, but for the
+ * moment I'm making the simlifying assumption that it
+ * is horizontal.
+ ****************************************************/
+cowl_height = 550;  
+
+floor_length = 1100;
+floor_width = 1500;
+
+/*****************************************************
+ * TODO: I need to calculate the lengths of everything
+ * which bonds to the front or rear bulkhead from the
+ * layback angles, but I'm being lazy for now
+ ****************************************************/
+layback_angle_f = 60;
+layback_angle_r = 60;
+
+sheet_thickness = 8;
+sill_max_height = bb_height;
+sill_min_height = 125;
+sill_width = 150;
+
+module battery_box_side( floor_length = 1100) {
+    fhl = (floor_length/2);
+    top_hl = 800; // calculate this later
+    rotate([90, 0 , 0])
+        linear_extrude( height=sheet_thickness) {
+            polygon([[ 0 - fhl, 0], 
+                [ fhl, 0], 
+                [ top_hl, bb_height],
+                [ 0 - top_hl, bb_height]]);
+        }
+}
+
+module battery_box( floor_length = 1100) {
+    top_hl = 800; // calculate this later
+    hbbw = bb_width/2;
+    translate([0, hbbw, 0])
+        battery_box_side( floor_length);
+    translate([0, 0 - (hbbw + sheet_thickness), 0])
+        battery_box_side( floor_length);
+    translate([0, 0 - hbbw, 0])
+        cube([sheet_thickness, bb_width, bb_height]);
+    translate([0, 0 - sheet_thickness, bb_height])
+        cube([1600, bb_width + (sheet_thickness * 2),
+            sheet_thickness],
+        center = true);
+}
+
+module sill( floor_length = 1100) {
+    cr = 5000;
+    fhl = (floor_length/2);
+    top_hl = 800; // calculate this later
+    difference() {
+        rotate([90, 0 , 0])
+            linear_extrude( height=sill_width) {
+                polygon([[ 0 - fhl, 0], 
+                    [ fhl, 0], 
+                    [ top_hl, sill_max_height],
+                    [ 0, sill_min_height],
+                    [ a_pillar_y, sill_min_height],
+                    [ a_pillar_y, cowl_height],
+                    [ 0 - top_hl, cowl_height]]);
+            }
+        rotate([-3, 0, 0])
+            translate([0, cr - (sill_width/2), 0])
+                cylinder( h = cowl_height, 
+                r = cr);
+    }
+}
+
+module front_bulkhead() {
+}
+    
+
+cube([floor_length, floor_width, sheet_thickness],
+        center=true);
+battery_box();
+
+translate([0, ( floor_width/2) + (sill_width/2), 0])
+    sill();
+
+mirror([0, 1, 0])
+    translate([0, 
+        ( floor_width/2) + (sill_width/2), 0])
+        sill();
+
diff --git a/model/fourbar.scad b/model/fourbar.scad
index 873e75c..6bead8f 100644
--- a/model/fourbar.scad
+++ b/model/fourbar.scad
@@ -99,5 +99,5 @@ module fourbar(length=1000, chord=100, lat_skew=30, long_skew=30, shoulder=650)
 }
 
 
- fourbar(length=800, chord=100, long_skew=30, lat_skew=35, shoulder=650);
+// fourbar(length=800, chord=100, long_skew=30, lat_skew=35, shoulder=650);
 // fourbar_axle_half();
\ No newline at end of file