stress in sailboat hulls

[bntii]

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?

[nero]

Can you post a photo?

[MikeJohns]

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.