I was there just after Christmas. We rented a boat at the national park where all the iguanas are (La Azufrada) for about 1000 pesos for 6 people but that was just to go and see the crocodiles...we only saw the head of one croc in the water! We wanted to go to the Isla Cabritos to go and see the flamingos but the guy said that there were no flamingos at that time and that they were on Laguna del Rincon, south east of Enriquillo. When in that area there is an excellent restaurant in the town of Duverge called Ramada Restaurante. From the outside it just looks like a shack but inside there is a nice air conditioned section which is really welcome as the temperature around Enriquillo is very hot! 6 of us went there and the food was excellent. The smoked eggplant parmesan was delicious!
Just ask around any area of the lake. In the small communities everybody knows everybody. There are people who know someone who has a boat or where to go to find a boat. Don't be shy, If you approach a group of motoconchistas it is almost certain one of them will know where to go and/or who to see. In many cases one of them will show the way for a small tip. Just be friendly.
From memory , in postings dating back quite some years ago , there were instances when no boat was available because the motors needed some repairs . I wonder if the crocodiles will try to rock the boat over . Maybe most of them have already been killed for their skin and for food .