13a. Worry about party bore (7)
.
.
?a??a?e
Second a most likely wrong
15d. Old tub,originally non-imperial,with a depth gauge .(11)
??t?o?e?r?c
Astrometric?
If so second a in 13a is correct.
Really stuck here. Begging for help!
15d might be BATHYMETRIC - see: http://en.wikipedia.org/wiki/Bathymetry
I see the bath (tub) and the metric (non-imperial), but I don't see where the Y comes from.