  Light curves of the long-period Algols are known for their complex shape
(asymmetry in the eclipse, light variations outside eclipse, changes from
cycle-to-cycle), and their interpretation is not possible in the standard model
of binary stars. Complex structures present in these active Algol systems could
be studied with the eclipse-mapping method which was successfully applied to
the new 7-color photometric observations in the Geneva system of W Cru,
belonging to the isolated group of these active Algols. Several cycles of this
long-period (198.5 days) eclipsing binary have been covered by observations. We
have used a modified Rutten's approach to the eclipse-mapping. The optimization
of the system's parameters and the recovery of the disk intensity distribution
are performed using a genetic algorithm (GA). It is found that a hot component
is hidden in the thick accretion disk which confirms previous findings. The
mass of the component, M1 = 8.2 Ms indicates that it is a mid-B type star. The
mass-losing component is filling its critical lobe which means it is a G-type
supergiant with a mass M2 = 1.6 Ms. The disk is geometrically very extended and
its outer radius is about 80% of the primary's critical lobe. A reconstructed
image reveals a rather clumpy and nonuniform brightness distribution of an
accretion disk rim in this almost edge-on seen system. This clumpyness accounts
for light curve distortions and asymmetries, as well as for secular changes.
