Small fishermen use two crafts in the fishing process in Manzala Lake. The first is  known as Al_ Dobba craft, and the second is known as Al_Jawabi craft. The study aimed to analyze the sensitivity of criteria for evaluating the efficiency of investment in Al_Dobba craft in Manzala Lake, based on a stratified random sample of only 291 Al_Dobba fishermen from the two study areas , namely, El_Gamaleya district (includes 194 fishermen) and El_Matareya district (includes 97 fishermen)  , Dakahlia Governorate. Data were collected from 30 fishermen from Al-Dobba craft in El_Gamaleya and 34 from Al-Dobba craft in El_Matareya , with a total of 64 fishermen in Al-Dobba craft, representing about 22% of the total number of fishermen in Al-Dobba craft in the two study areas. The results of the study showed the feasibility of investing in Al-Dobba  craft in Manzala Lake in the two study areas. The sensitivity analysis also showed that there are many factors that affect the profitability of this investment, and that the most influential are the potential changes in the amount of tilapia caught and in the total cash outflows.