We have used the Nançay Radio Telescope to obtain new global H i data for 16 giant low surface brightness ( LSB ) galaxies .
Our targets have optical luminosities and disk scale lengths at the high end for spiral galaxies ( L _ { B } \sim 10 ^ { 10 } L _ { \odot } and h _ { r } \mathrel { \hbox { \hbox to 0.0 pt { \hbox { \lower 4.0 pt \hbox { $ \sim$ } } } \hbox { $ > $ } } } 6 kpc for H _ { 0 } =75 km s ^ { -1 } Mpc ^ { -1 } ) , but they have diffuse stellar disks , with mean disk surface brightnesses \mathrel { \hbox { \hbox to 0.0 pt { \hbox { \lower 4.0 pt \hbox { $ \sim$ } } } \hbox { $ > $ } } } 1 magnitude fainter than normal giant spirals .
Thirteen of the galaxies previously had been detected in H i by other workers , but the published H i observations were either confused , resolved by the telescope beam , of low signal-to-noise , or showed significant discrepancies between different authors .
For the other 3 galaxies , no H i data were previously available .
Several of the galaxies were resolved by the Nançay 3 ^ { \prime } \hskip { -4.836969 pt } . \hskip { 0.0 pt } 6 E-W beam , so global parameters were derived from multiple-point mapping observations .
Typical H i masses for our sample are \mathrel { \hbox { \hbox to 0.0 pt { \hbox { \lower 4.0 pt \hbox { $ \sim$ } } } \hbox { $ > $ } } } 10 ^ % { 10 } { M } _ { \odot } , with M _ { HI } / L _ { B } = 0.3-1.7 ( in solar units ) .
All of the observed galaxies have published optical surface photometry , and we have compiled key optical measurements for these objects from the literature .
We frequently find significant variations among physical parameters of giant LSB galaxies reported by various workers .