Well - we have, along with other Nereid Rally participants and you know - its not so tough! Yes, you get a counter-current, though it really isn't so bad at this time of year. Its an upwind sail, but the seas aren't large and the going is relatively easy. Others have sailed the whole way, so its definitely possible. We motored the north Trinidad coast, and had a bit of motorsailing to get us a bit more 'pointing'. To put it in context, it was only marginally longer than our biscay crossing.
Rewinding a bit - we had a few hours of motorsailing to get us back on course overnight but by 10pm the wind had shifted back to the East and we were sailing very nicely. We timed our arrival at the outer waypoint for bang on daybreak. We'd seen a few fishing boats as we approached the shallower water - but nothing difficult to deal with. So as day broke, we were at the GWST00 waypoint from the Doyle's guide update. In the distance, we could see another yacht - Gaia, another rally member who had left from Tobago 1.5 days before us, and sailed the whole way. They were using genoa alone, but we still had full sail. With the tide we were doing 8.5knots up the river. Within a mad 5 minutes, we'd spoken to Gaia on VHF, Ocean Rainbow on Iridium Satphone and Piano on SSB.
We only had one obstacle on our way up the river - a huge drift net was on the direct line - but we found enough depth around it on the western end. We notified Gaia and also e-mailed those in the Nereids rally fleet we could. We'll keep a watch on VHF and SSB to tell others if we can.
So both Duplicat and Gaia are anchored in the river, just up from Wakenaam Stelling. We'll spend the night here, and head up to Bartica with the morning tide tomorrow. Not sure if we'll sail up as the winds will get a lot more fickle and the charts are useless - we need to stay on the route listed in the guide and its updates to be safe. Motor may be best for that...