existing ribs. They need to be dried out thoroughly. Rough edges on the cracks should be cleaned up and perhaps tapered a bit at the edges.
I would use a couple of layers of bias cut FG over the broken portions. The tricoky part is to get the new glass to conform to the rib contours while the resin hardens. I don't think you want to get into vacuum bagging. I would wet the cloth in place as neatly as possible, put some food wrap film over it, and then push some soft foam (similar to urethane upholstery foam) onto the cloth, adding a hard thin board and some weight. This should be rehearsed in advance and the strategy adjusted as necessary.
Bias cutting cloth is crucial when one needs to get it to conform to changing contours. You may find that pulling the bias cut repair pieces along the axis of the rib will make them even more inlined to make the desired direction changes.
I've used a similar strategy when glassing over the center rib on a paddle face. Your situation may be more challenging, and I hope there are other suggested approaches to consider.
Deck Rigging Gear
Hardshell Kayak Sail Rigs
|Table of Contents|