Grappling iron (7)
(Other definitions for grapnel that I've seen before include "Clawed grasping device" , "Light anchor for small boats" , "Grappling hook" , "Hook on rope" , "Small anchor with three or four flukes" .)
'grappling iron' is the definition.
(crampon is a kind of grappling iron)
This is all the clue.
(Other definitions for crampon that I've seen before include "Grappling-iron" , "helps climber on ice" , "Climbing device" , "Spike attached to the shoe to prevent slipping when climbing" , "Climber's device" .)