This is the practical Essequibo boat service rather than a tour: scheduled crossings from Parika to Supenaam and Wakenaam, and between Supenaam and Wakenaam, plus cargo.
For visitors the useful part is the private charter — up to Bartica and Aruwai, out to Fort Island, or to the Baracara falls — on a boat you have to yourself rather than an itinerary somebody else set.
Prices are quoted rather than published, and they advertise WhatsApp as available around the clock, which for river transport that runs on tides and daylight is the sensible way to reach them.