scale=170/1800;   // only used to scale the drive shaft x,y,z
                                 // this is mm beam / mm beam, ie, 17cm from 1.8 meters.
                           // everything else was hardcoded, so this parameter
                           // isn't that useful to achieve an arbitrary scaling.
 
 shaftangle=5.340021;  // as taken from drawing (and then from awk code)
 shaftlength=4626.94 * scale;  // shaft length, then scaled down for printing
 shaftdia=6;   // mm of outer brass tube. Measures 5.62mm
                             // 5.66mm wasnt quite enough clearance
 
 shaft_x=7675*scale;
 shaft_y=0;
 shaft_z=-89*scale;
  
  rudderpost_x=717;  // mm
  ruddershaftdia=3;  // mm
  
  motoraccess_x=230;  // mm , rememeber x is along the length of the boat
  midaccess_x=400;
  rudderaccess_x=686;  
  
  //$fa=5;
  $fn=50;
  
//intersection()  // this or union() to choose a section, or show all. And change both the *0 to *1 below on each
union()        // line to enable that section.   The x on each line (cube() and translate()) sets the offset, that is
   {                      // adative, starting at the bow
  translate([0,-100,100-105])
      union(){ cube([150,20+200*0,20+100*0]); translate([150,0,0])union(){
                             cube([155,20+200*0,10+100*0]); translate([155,0,0])union(){
                                    cube([155,20+200*0,20+100*0]); translate([155,0,0])union(){
                                          cube([125,20+200*0,10+100*0]); translate([125,0,0])union(){
                                               cube([110,20+200*0,20+100*0]); translate([110,0,0])union(){
                                                     cube([35,10+200*0,10+100*0]); translate([35,0,0])union(){
                                                        }
                                                   }
                                             }
                                    }
                             }
                   }
          }
  
  
  difference()  // entire boat , subtract prop shaft and rudder shaft
  {
  
      union()  // boat skin (+lid lip) + internal prop support
         {
     
               difference()   // make a boat shell, with lid lip
                 {
                     union()
                       {
                          import("boat_scaled.stl",convexity=10);
                          import("block_scaled.stl",convexity=10);
                           
                           translate([0,0,51])    // motor+rudder access lip
                                 hull()
                                    {
                                          translate([rudderaccess_x,-10,0])cylinder(r=32+3,r2=32+2,h=19);
                                          translate([rudderaccess_x,10,0])cylinder(r=32+3,r2=32+2,h=19);
                                          translate([midaccess_x,-28,0])cylinder(r=32+3,r2=32+2,h=28.5);
                                          translate([midaccess_x,28,0])cylinder(r=32+3,r2=32+2,h=28.5);
                                          translate([motoraccess_x,-26,0])cylinder(r=32+3,r2=32+2,h=34);
                                          translate([motoraccess_x,26,0])cylinder(r=32+3,r2=32+2,h=34);
                                    }                      }
                    union()
                      {
                         import("boat_scaled_inside.stl",convexity=10);
                   
                         //translate([0,-100,60])   // cut top off to see what is going on
                          //   cube([800,200,50]);
                                                           
                          translate([0,0,50])    // (star this to create boat_combineall_nohatch.stl)
                               hull()  // rudder access cutout
                                  {
                                      translate([rudderaccess_x,-10,0])cylinder(r=32,h=29);
                                      translate([rudderaccess_x,10,0])cylinder(r=32,h=29);
                                      translate([midaccess_x,-28,0])cylinder(r=32,h=35);
                                      translate([midaccess_x,28,0])cylinder(r=32,h=35);
                                     translate([motoraccess_x,-26,0])cylinder(r=32,h=43);
                                      translate([motoraccess_x,26,0])cylinder(r=32,h=43);
                                  }
                        }
                }
 
            intersection()
              {
                 import("boat_scaled_inside.stl",convexity=10);
    
                 union()
                   {   
                      translate([shaft_x-0*scale,shaft_y,shaft_z])   // internal prop shaft support block
                           rotate([0,-shaftangle,180])
                               translate([190,-4,-30])
                                   cube([2400*scale,8,30]);
                       
                       // motor support block. well, the feet, the block is best done sep.
                       translate([220,-10+30,0])rotate([0,shaftangle,0])cube([70,20,25]);
                       translate([220,-10-30,0])rotate([0,shaftangle,0]) cube([70,20,25]);
                       // over sized motor support block, to find distance between height of support block and prop shaft
                       //translate([220,-10-30,0])rotate([0,shaftangle,0])cube([50,100,50]);
                       // which was measured in meshlab to be 10.51mm above top face of motor mounts
                       
                       // rudder post
                       translate([rudderpost_x,0,10])
                           cylinder(35,8,8);
                   }
              }
      }
  
      union()  // things to subtract, prop shaft and rudder shaft
        {
           // prop shaft to subtract    
           translate([shaft_x,shaft_y,shaft_z])
                 rotate([0,shaftangle-90,0])
                     cylinder(shaftlength+200,shaftdia/2,shaftdia/2);  // add 200 to shaft length, making a hole in the optional oversized support block above, to see how far above the shaft is from the motor mount blocks
          // rudder shaft
          translate([rudderpost_x,0,10])
                cylinder(35,ruddershaftdia/2,ruddershaftdia/2);   
            }
 }
 
 }   // overall intersection() or union(), to show entire object or just chop out a printable section