suitable construction in the preferred embodiment however each spacer comprises a first pipe section and a smaller second pipe section which can slide in telescopic fashion within the first pipe section preferably each pipe section has a linearly arrayed series of pin holes for receiving a retainer pin the second pipe section is positioned as desired within the first pipe section with at least one pin hole of each pipe section being in alignment whereupon one or more suitable retainer pins can be dropped through the aligned pin hole s thus temporarily fixing the length of the spacer to suit the length of the fitting to be installed in the spacer location one end of the spacer will be a u201c male u201d end and the other end will be a u201c female u201d end adapted for engagement with typical pipe sections 70 being laid in trench 80 or secondary channel 82 the collapsible spacers thus make it possible to install the full length of the pipeline using the apparatus and method of the present invention in a continuous fashion without needing to interrupt pipe laying operations to install valves and tees and the like after the pipeline has been laid out.