The CG Sould be found on the VHF Marine Band.
Channel 16 (156.8Mhz) Distress and calling channel
Channel 22A (157.1Mhz) CG liason with the public
Channel 21A (157.05Mhz) CG working channel
Channel 23A (157.15Mhz) CG working channel
Channel 83A (157.175Mhz) CG working channel
You should try all the CG working channels, since they are rotated to avoid interfernce by near by CG units. Most modern scanners have a service search range of VHF Marine Channels and you should try this for other marine/boating radio traffic.
Hope this helps,
Larry