I was a riverine operator in the US Navy about a dozen years ago, and used to interact with the Customs & Border Protection (CBP) riverine guys from time to time. Back then, they used a green Coast Guard-type slash on their hulls like this:
![](https://farm8.staticflickr.com/7858/46426557622_8a20da0bcc_c.jpg)
![](https://farm5.staticflickr.com/4887/46431518452_beca904c35_b.jpg)
Source: US Customs & Border Protection website
That seems to have changed sometime after 2014 to a wide blue, narrow red stripe:
![](https://farm5.staticflickr.com/4830/46426558382_56deb4a5b8_b.jpg)
Source: US Customs & Border Protection official photo via Wikimedia.org
![](https://farm5.staticflickr.com/4886/45755098154_3324a1f296_b.jpg)
Source: US Customs & Border Protection Info sheet: "Interceptor Class All-Weather 33-Foot SAFE Boat"
V/r
Jim