Corrosion rear crossbar

I can see some corrosion at the rear crossbar when I look beneath the stainless steel bolt from the outside of the hull.
Has anyone do this repair...or is it even possible to do something about it?
I also understand that this is the main problem of the 17....

The H17 crossbars seem to be highly succeptible to corrosion and cracking especially when in a salt water environment. The rear crossbar will crack on the bottom side perpendicular to the axis of the crossbar and right through the bolt hole.

Hobie did modify the reinforcement plate on the inside of the crossbar at one point. The original reinforcement plate was very small (about 1" square). The plate was later extended to be the same length as the reinforcement plate in the front crossbar (about 3" long) so the reinforcement on the rear crossbar extends well beyond the inboard edge of the hull to help spread out the load.

If you have a lot of corrosion around the rear crossbar bolts, I would suggest you remove the crossbar and inspect. Drill out the rivets that hold the reinforcement plate in place. Use an aluminum wire brush to remove any corrosion residue. Then, if your boat already has the larger reinforcement plate, re-install the plate. If your boat has the small reinforcement plate, upgrade to the larger plate. I would suggest applying a generous amount of anti-corrosion paste (tefgel) between the reinforcement plate, the stainless steel rivets, and the crossbar. Also be sure to rinse all aluminum parts thoroughly after sailing in salt water.