Most lobster traps, called "pots," follow the same basic funnel-shaped design pattern. A lobster is lured into the wide section of a funnel by the presence of bait, continues into a cage, and then is unable to exit from the narrower end of the funnel. The cage itself comes in many different shapes, but the trapping mechanism for this simple and effective design is generally the same. Traps with multiple funnels catch more lobsters, so the "bedroom and parlour" design (two-funnel trap) has become standard.
Making the cell
Cut four pieces of plastic tubing to 75 cm (30 inches) in length, and eight pieces of plastic tubing to 50 cm (20 inches) in length. Build a rectangular box. If using PVC pipe, use elbow-pieces for the joints, if using any other types of plastic tubing, either find elbow pieces that suit the design or install mounting brackets for the joints.
Drill drainage holes in the PVC pipe along the top and at the corners.
Cut the plastic meshing to fit around the long side of the rectangular box. If using the dimensions above, the mesh should be cut to 75 cm x 2 m (30 inches x 80 inches).
Attach the plastic meshing along the side of the box using heavy-duty zip ties.
Building and installing the funnels
Cut two circles out of the mesh and fold them into funnel shapes.
Secure with zip ties. Make sure the wide portion of each funnel is large enough to span the trap opening and the small portion is big enough to allow a lobster to enter.
Cut the large end of the funnel so that it is no larger than the opening, and secure one of the funnels halfway down the side of the cell, and the other at the front opening.
Finishing the trap
Cut the final portion of mesh-wiring to fit over the back of the trap and secure with zip ties.
Attach a long rope so that it passes through the mesh and around the PVC pipe. Tie the rope to the trap. Throw the trap in the water and secure the other end of the rope to something on the surface, a buoy, for example. If fishing in an area with a rough tide, consider adding some additional weight to the trap -- about 2.27 kg (5 lb) to help it stay settled on the ocean floor.
Place the bait on the opposite side of the entrance. This should be chicken heads, fish, or animal bone. Encase the bait in bait container made of wire or plastic mesh, and secure the bait container with twine.
If you want to save the bait, put it in a metal container with holes drilled in it. But if you use this method, make sure the bait is extremely attractive to the lobsters you are trying to catch.