We present a new set of deep H I observations of member galaxies of the Fornax cluster .
We detected 35 cluster galaxies in H I .
The resulting sample , the most comprehensive to date , is used to investigate the distribution of neutral hydrogen in the cluster galaxies .

We compare the H I content of the detected cluster galaxies with that of field galaxies by measuring H I mass-to-light ratios and the H I deficiency parameter of Solanes et al .
( [ 1996 ] ) .
The mean H I mass-to-light ratio of the cluster galaxies is 0.68 \pm 0.15 , significantly lower than for a sample of H I -selected field galaxies ( 1.15 \pm 0.10 ) , although not as low as in the Virgo cluster ( 0.45 \pm 0.03 ) .
In addition , the H I content of two cluster galaxies ( NGC 1316C and NGC 1326B ) appears to have been affected by interactions .
The mean H I deficiency for the cluster is 0.38 \pm 0.09 ( for galaxy types T = 1 – 6 ) , significantly greater than for the field sample ( 0.05 \pm 0.03 ) .
Both these tests show that Fornax cluster galaxies are H I -deficient compared to field galaxies .
The kinematics of the cluster galaxies suggests that the H I deficiency may be caused by ram-pressure stripping of galaxies on orbits that pass close to the cluster core .

We also derive the most complete B -band Tully – Fisher relation of inclined spiral galaxies in Fornax .
A subcluster in the South-West of the main cluster contributes considerably to the scatter .
The scatter for galaxies in the main cluster alone is 0.50 mag , which is slightly larger than the intrinsic scatter of 0.4 mag .
We use the Tully – Fisher relation to derive a distance modulus of Fornax relative to the Virgo cluster of -0.38 \pm 0.14 mag .
The galaxies in the subcluster are ( 1.0 \pm 0.5 ) mag brighter than the galaxies of the main cluster , indicating that they are situated in the foreground .
With their mean velocity 95 km s ^ { -1 } higher than that of the main cluster we conclude that the subcluster is falling in to the main Fornax cluster .