Stress intensity factors (SIFs) are important parameters in brittle fracture assessment of marine notched components; in respecting of previous researches, it has found that there are several ways for SIF solutions. Following outline of LEFM based fatigue analysis; the paper has proposed a closed-form SIF solution as an alternative way for ship structural details prediction. It has shown that the stress intensity factors (SIFs) can be solved revealing the effect of the geometric parameters. Numerical tool has offered an evaluation as convergence behavior of relative SIF results between CCT (central crack) and DENT (double edge notch). Then the proposed methodology is applied onto the construction similar to HHI #1 and #2 specimens. It has be concluded in results that the SIFs and fatigue lives by the proposed method have good agreement with those by FEA calculations, furthermore, these key parameters can be expressed in formula format. For real engineering application, the main advantage of the proposed method will be useful for fatigue prediction rapidly and conveniently.