Some embodiments of the present clamps include a first clamp portion having a first end defining a recess and a second end configured to be coupled to a first structure, a second clamp portion having a first end configured to be coupled to a second structure and a second end configured to be received in the recess of the first clamp portion, and a shear pin configured to secure the second clamp portion relative to the first clamp portion. Some embodiments include a retaining member disposed in the recess. In some embodiments, the recess and/or retaining member is configured to resist shearing of the shear pin if a force is applied to the second clamp portion in a first direction, but not if the force is applied in a second direction. In some embodiments, the first direction is substantially parallel with, but opposite to, the second direction.