My 405 has some surface rust on the keel bolts but I have not been concerned by it. Suggest you put your hand over the bolts while pounding through a sloppy sea because if you feel them move, you have a problem. If they are OK, you should feel no movement at all. However, if in doubt, suggest you have a couple taken out in the first instance to inspect properly. Regards David Murray "PORTIA" engineer@appi.com.au
