Originally Posted by scottyt
they are not really pvc they are specific covers west marine sells em link below
The OP was referring to "covers" 3-4 feet long - I think they probably were PVC or ABS pipe as the turnbuckle covers don't come that long. The larger diameter pipe sections do a better job of avoiding hangups on shrouds and especially babystays and also the sheets generally contact these areas above the height of the normal turnbuckle covers mentioned above during tacks.
I'd leave the pipe sections in one piece, and as KH suggests, exercise your turnbuckles while you're at it. You'll have to decide whether you'd prefer white or black plastic pipe... sometimes black is a bit less obviously visible. For a cleaner look you can use solvent to remove the markings usually printed on these types of pipes. Another (lighter but less strong) option might be the pipe sections used in central vacuum systems for homes.