I designed and built the EZ Tunnel in an attempt to simplify the tunnelboat building process. Construction of the EZ Tunnel is based on a series of transverse and longitudinal plywood bulkheads, girders and basic structures joined with 3/4" square cleats and glue blocks. No long stringers are needed. All shapes are created right on the plywood sheets and installed on a tunnel plank that extends the full width of the hull.
See the construction process HERE.