he3r0
Registered
Same thing happened to me. Brand new Force Knife, 40 quid, attached it to my Mares BCD, jumped in, knife gone. Lucky I found it again, but now it's on a lanyard. Basically the sheath is poorly designed.
yeah, i`ve made this video YouTube - ‪mares‬‏
and over here is semi-fix i've made Mares force dive knife | Muziol.com
does not fix issue completely, but it is way more sturdy than factory design.