2-58 BOAT HULL DESIGN 



Check bond so that the faces will not break away from the core. 



Critical stress for face buckling f cr 



" 2 V E Face x E Core x G Core (See Chapter 6) (2.36) 



= 1 V 1.9$ x 10 6 x 1.0 x lcA x 2 x lO 3 

 (For 6 lb. per cubic ft. CCA) 



= 17000 psi. Satisfactory 



Buckling of the panel itself in way of the mast is not a problem due to the close prox- 

 imity of transverse bulkhead No. 3. 



Fittings: The chain plate calculation is similar to that for the open sailing boat 

 (Design Example 2-2). 



Typical cleat attachment: Consider a jib sheet cleat intended to handle a 1/4 in. diame- 

 ter manila line. The cleat is a standard item and is provided with holes for 2 fasteners. 



Design the fasteners for the breaking strength of the 1/4 in. diameter manila line = 

 550 lbs. (17). 



Consider two loading directions, a horizontal pull and a vertical pull (see Fig. 2-2 8). 



VERTICAL PULL 

 1 



HORI Z0NTAL PULL 



=t 



1-1/2" 



H 



1-1/2" 

 Fig. 2-2 8. Loading of cleat 



Axial Load on Fastener - From vertical pull = —x- = 275 lbs. 



From horizontal pull - to resist overturning 

 moment = 550 lbs. 



Transverse Load on Fastener - assuming equal distribution = — — = 275 lbs. 



Factor of Safety = 2.0 



Use a threaded fastener of the self -tapping, thread cutting type with a mat insert in 

 place of the nonstructural core of the deck. The fastener should not go all the way through 

 the deck. 



