Please can you confirm which version of shinobicharts you are using?
My colleague has reminded me that there was an issue in versions <2.9.4 where the crosshair's line drawer was not being created by default. It was fixed in version 2.9.4. You could either try upgrading to the most recent version of shinobicharts, or add in the following line when creating your crosshair:
myCrosshair.lineDrawer = [SChartTargetLineDrawer new];
Please let me know if that helps.