A raft assembly for a gas turbine engine is provided. The raft assembly includes a rigid raft formed of a rigid material that has an electrical system and/or a fluid system embedded therein. The raft assembly further includes one or more clamps for mounting tubular members to the raft. The or each clamp has a first clamp block and a second clamp block which, in use, clamp together to grip a tubular member between the blocks. The first block is fixed to the raft. The or each clamp further has a fastener operatively extending between the blocks. The fastener is tightenable to apply a clamping load between the blocks, and releasable to remove the clamping load such that the second block can be moved relative to the first block to allow the tubular member to be received between or removed from between the blocks.