A compression lock assembly for an adjustable length rod assembly with inner and outer tubes is provided. The compression lock assembly has an adapter adapted to be connected to rotate with the inner tube. An elastomeric ring with an inner opening and outer diameter is concentric and disposed coaxially with the adapter. A threaded fastener extends through the elastomeric ring and is fixed to the adapter. A lock nut is disposed about the threaded fastener and fixed to rotate with the elastomeric ring. The locking nut moves along the threaded fastener to compress the elastomeric ring and expand the outer diameter from a first diameter to a second diameter greater than the first diameter as the elastomeric ring is rotated relative to the adapter.

A guide rail assembly for a submersible machine as well as a guide rail holder for such a guide rail assembly is described herein. The guide rail holder includes a radially extending support body and an axially extending post, which is rigidly connected to the support body and which is adapted to be inserted into an end of the guide rail. An engagement head is connected to the post at a distance from the support body and has a greater radial extension than the post. The engagement head includes a radially expandable member that is adapted to be reversibly manipulated between an active state, in which the expandable member is in engagement with the guide rail, and an inactive state, in which the expandable member is disengaged from the guide rail.