We consider global HI and optical properties of about three hundred nearby galaxies with V _ { 0 } < 500 km/s .
The majority of them have individual photometric distance estimates .
The galaxy sample parameters show some known and some new correlations implying a meaningful dynamic explanation : 1 ) In the whole range of diameters , 1 — 40 Kpc , the galaxy standard diameter and rotational velocity follows a nearly linear Tully-Fisher relation , \lg A _ { 25 } \propto ( 0.99 \pm 0.06 ) \lg V _ { m } . 2 ) The HI mass-to-luminosity ratio and the HI mass-to- ” total ” mass ( inside the standard optical diameter ) ratio increase systematically from giant galaxies towards dwarfs , reaching maximum values 5 M _ { \sun } / L _ { \sun } and 3 , respectively .
3 ) For all the Local Volume galaxies their total mass-to- luminosity ratio lies within a range of [ 0.2–16 ] M _ { \sun } / L _ { \sun } with a median of 3.0 M _ { \sun } / L _ { \sun } .
The M _ { 25 } / L ratio decreases slightly from giant towards dwarf galaxies .
4 ) The M _ { HI } / L and M _ { 25 } / L ratios for the sample galaxies correlate with their mean optical surface brightness , which may be caused by star formation activity in the galaxies .
5 ) The M _ { HI } / L and M _ { 25 } / L ratios are practically independent of the local mass density of surrounding galaxies within the range of densities of about six orders of magnitude .
6 ) For the LV galaxies their HI mass and angular momentum follow a nearly linear relation : \lg M _ { HI } \propto ( 0.99 \pm 0.04 ) \lg ( V _ { m } \cdot A _ { 25 } ) , expected for rotating gaseous disks being near the threshold of gravitational instability , favourable for active star formation .