2-4 



BOAT HULL DESIGN 



a. LONGITUDINAL 



b. TRANSVERSE 



Fig. 2-5. Hull framing 



Fig. 2-6. 56' Deborine hull. - Transversely stiffened 

 single skin (Courtesy P.O. De Laszlo) 



support the shell rather than the larger frames. In addition to this primary framing system, 

 local stiffening must sometimes be added in way of local loads. This stiffening, where 

 possible is oriented to resist the applied load most effectively. For an example of a stiffened 

 single skin hull- see Fig. 2-6. 



The choice of framing orientation depends largely on a compromise between the interior 

 arrangement and economical construction of the boat. In wood frame and plank construction, 

 transverse framing is necessary because the planks run longitudinally and the frames must 

 be perpendicular to them to provide proper support and fastening, Fig. 2 -2b. In fiberglass 

 construction this is not necessary, and the designer has greater freedom of choice. In the 

 .normal small boat, transverse members are in the form of bulkheads, tanks, and seats which 

 provide support for the longitudinal framing. In larger boats with cruising accommoda- 



