The Do318 was a development of the Do 24 with larger dimensions and higher all-up weight. When used for maritime rescue, the all-up weight was to be 18 tonnes, while the long-distance reconnaissance version had an overload all-up weight of 20 tonnes. The two-step hull was to be of the usual monocoque design. For the three-section wing with a slight sweepback, NACA 230 was the profile selected. The long-distance reconnaissance version used a mixture of exhaust gas and compressed air for wing, horizontal stabilizer and propeller de-icing. The powerplant was to consist of 3 Bramo 323TAs rated at 1200 HP take-off thrust each. In sea rescue service, eight shipwrecked could be taken up, and there was to be a crew of five.
Dornier Do 318
Type SAR flying boat
Engine 3 Bramo 323 TA
Dimensions Length 24.00 m, height 6.20 m, span 30.00 m, wing area
Weights Flying weight (SAR)  18000 kg, (Rec.) 20000 kg