“While vertical cracks in swaged fittings (typically a sign of internal corrosion) are bad enough, horizontal cracks indicate the need for IMMEDIATE corrective action. Such fittings have no safety margin (meaning they could fail at any moment) and must be replaced as soon as possible. As the rest of the rigging is probably the same age, it should be thoroughly inspected as well prior to placing the vessel back into service. Horizontal cracks are generally caused by metal fatigue, rather than corrosion.”