BOAT HULL DESIGN 2-65 



P b 

 The renuired thickness, t = (2. 12) 



D * f Ba 



0.153 in. 



0.5 x li583 



Use 5 plies of woven roving, t = .185 in. (Table 5-2) 



Use a stiffener width of 2 in. for ease in molding. This stiffener is carried forward 

 to support the cabin floor. 



Decks: All decks are to be of sandwich construction for rigidity. Type B sand- 

 wich is used Fig. 6- 53b. Each deck is checked for stress in the various elements, 

 and for deflection. 



The required core thickness for each criterion, stress or deflection, is determined 

 and the thickest core is used. 



Cabin Top - Lower Level: 



Design Load; p = 2 ft. of water = 0. 89 psi 



Dimensions: Length = 6 ft. - 5 in. , width = 7 ft. - in. 



Edge Connection: Fixed 



Flexure: Consider a 1 in. strip as a fixed ended beam. 



Bending moment, M = §P = °- 8 ^ x h& = 171 in. -lbs. (2.21) 



Required section modulus = Z = — — (2. 22) 



TJltimate stresses, Fu, from Tables 5-6 and 5-11 

 Cloth; top face in tension, 7, = — : — -p— = 0.028 in.3 



1/2 in. deep core required (Fig. 6 -53b) 



Woven roving; bottom face in compression, Z = * = 0.0h9 in. 



7/8 in. deep core required (Fig. 6-53b) 



h x 1.71 n nAo . 3 

 Kat; top face in tension, Z = — - O.utv. in.-' 



l/2 in. deep core requireu (Fig. 6 -53b)* 



* By extrapolation. 



