§3.279 Bottom loads.

(a) Main seaplane float bottoms shall be designed to withstand the following local pressures: (1) A limit pressure of at least 10 pounds per square inch over that portion of the bottom lying between the first step and a section 25 percent of the distance from the step to the bow. (2) A limit pressure of at least 5 pounds per square inch over that portion of the bottom lying between the section 25 percent of the distance from the strip to the bow and a section 75 percent of the distance from the step to the bow. (3) A limit pressure of at least 3 pounds per square inch over that portion of the bottom aft of the step (aft of main step if more than one step is used). (b) The local pressures determined in paragraph (a) (1), (2) and (3) of this section shall be applied over local areas in such a manner as to cause the maximum loads in local structure such as bottom plating and stringers. (c) For the purpose of designing frames, keels, and chine structure, distributed bottom pressures equal to one-half of the local values specified above shall be applied over the entire specified bottom areas. WING-TIP FLOAT AND SEA WING LOADS