Old sonobouy tubes are yer friend ;)
http://commanderzero.com/blog/2012/01/06/sonobuoy-transport-tubes/
seriously. Milspec water tight.
Black PVC pipe - everything vacuum sealed. And if you really want to confuse the ‘authorities’ you sprinkle 6p finishing nails in a wide circle - away from where you buried your arms.
PS - email my dad the page.