print part 1 2x (one for each side)
print part 2 or 3 2x

Table 2 is the mid section of the tank
Table 3 is the mid section of the tank with a lid. These fit the Maxi size Kinder Suprise egg containers. When you're done LOLing,... these make great watertight containers, and can easily house an Arduino Mini or Nano and a 9V battery.

Put 2 by 200mm threaded rod in de 4 holes of eache large piece and slide on the slim mountpieces and caps from part 2.
Put the tanks on a surface next to your SB-1, mark the height of the large 5mm holes in the mountpieces of the tank onto the hull of the SB-1 by drawing a line. This is the part of the (wet) hull that houses the dead ballast. on that line, mark 2 points at 13.7mm from each other (so 7.25mm from the center of the line) and mirror this on the other side of the hull.
Put a 5mm rod through the holes and attach the tanks to that. put locking rings at the end of the rods to secure the tanks (there are niches in the mountpieces to accomodate these, and a hole going from the bottom up so you can screw them tight with a hex key).