This is the River Corentyne, on the border between Guyana and Suriname. In colonial times, the border was established running up the middle of the river. But what happens out in the estuary? The question didn't really matter until the discovery of potential oil deposits.
For years, the Guyanese had been trying to set up a rig, and a Canadian company took up the task. But, in June 2002, it came to nothing when Suriname’s response was to send in an old gunboat. Guyana was unwilling or unable to escalate matters, and so - for a long time - there matters lay.
The Surinamese navy still keep up their presence (see picture). However, locals told me that this patrol boat wasn't often out on the river. Ironically, it seems that the navy can’t afford the fuel.