for “non-disturbed” rotation curve falls into this interval. The Tully-Fisher relationship in the $B$ band according to Rubin et al. (1985) shows that normal Sc galaxy with the luminosity of NGC 3808B must have the maximum rotational velocity of 160$-$165 km/s which is also in agreement with our model rotation curve. The use of the Tully-Fisher relationship in the $I$ band according to Byun (1992) leads to better agreement - $\rm V_{max}\,\approx\,170$ km/s.

Comparing observed and “non-disturbed” rotation curves one can conclude that strong gravitational disturbance together with mass transfer to NGC 3808B results in observed displacement of the global maximum of rotation curve to the center (approximately by $\rm 6"=2.7$ kpc) and in “braking” (approximately by 50 km/s) of the gaseous disk of the galaxy. The latter is in agreement with the conclusion of Reshetnikov (1994) who found that spiral galaxies in strongly interacting systems tend to have lower observational rotational velocities than the same field galaxies.

Interaction between gaseous disk of the galaxy and accreting gas of twined spiral arm may lead (besides of disturbance of the velocity field) to intensification of star-forming activity in NGC 3808B. Indeed, as it was pointed out in RC, NGC 3808B shows 