stress in sailboat hulls

Does someone have a good feel for how stress is distributed in a sailboat hull?

I have a hull which shows gellcoat cracking along the hull from rail to waterline from stem to stern. The crazing follows a forward and down pattern at about 65 degrees from sheer. The interesting thing is that the pattern does not vary much along the hull (forward and down). I have noted the band bracing specs for wood hulls as diagonals forward and aft from rail down in a apparent effort to strengthen the 'web' of the hulls vertical plane. It would seem that the glass hull does not need any help in sheer of the web and therefore I am observing gellcoat crazing from some other mechanism?? Perhaps rotation of the hull along the long axis? Or deflection outward as the deck and upper hull is compressed during load cycles?

 

Can you post a photo?

 

bntii

can you tell us what the vessel is, what layup is the hull core or solid GRP ?
What kind of use does the vessel get eg ocean boisterous coastal or sheltered ?

It sounds like stress crazing from the movement of the boat and you may need to add bulkheads to stiffen her up. Flexure of plastic hulls is always a problem and some are far worse than others.