Dependence of internal rate of return IRR0 (а) and annual revenues R (b) for the icebreaker as function of discounted payback period Θ and discount rate r for K = 127 Billion RUB, Y = 1.5 Billion RUB /year Тс = 8 years, Тo = 40 years and NPV = 0. Calculation performed using Formulas (7) and (4). 1 – Θ = 10 years; 2 – Θ = 15 years; 3 – Θ = 20 years; 4 – Θ = 40 years.