2-38 BOAT HULL DESIGN 



resistance to floating objects than the Type B. Since the service requirement of this boat is 

 for normal pleasure use, the Type B laminate as specified above is considered satisfactory. 



Typical Design Loads: 



Impact pressure from Fig. 2-lii 



Waterline Length, L = 18.5 ft. 



Speed, V = 3£ miles per hour 



V x L = 163. h 



p = 25.0 osi 



Determine Design Pressure At Station 7 



P D = P H + p l x F l (2. 3) 



p at 6 in. draft = Jl x 6U = 0.3 psi 



h 12 mu 



Jhere: =r? = head of water in ft. 



6I4. = weight per cubic ft. of salt water 



D1I4 = sq. in. per sq. ft. 



F ± = .60 from Fig. 2-1$ 



p D = 0.3 + 25.0 x 0.60 = 15.3 psi 



Laminate Design: Table 2-3. The panels of shell laminate formed by the longitudinal 

 and transverse supports are long and narrow, and the laminate is considered as a 1 inch 

 wide beam spanning between the longitudinals. Due to the continuity of laminate and the 

 uniform pressure loading, the beam is considered to have fixed ends. The maximum 

 moment occurs at the ends of the span, i. e. at the longitudinal, and places the inboard 

 face of the laminate in compression as indicated in Fig. 2 -10b. 



A typical deflection calculation is also shown. 



Deflection; d = — Shear deflection not considered (2.20) 



36b EI 



Assumed allowable d = _L- ;& TD = 1.81 x 10 6 (Table 5-10) 



100 WK 



Type A Laminate - Forward Station 5 



d = 25-3 CJ.3) li = 0.06 in. 



36h x l.ol x 10 6 x .000h6 



3 = n<- 



Allowable d = £j2. = .053 in. 

 100 



Calculated deflection is high, but acceptable because of innerbottom. 



