If and angler is hooked up and I see that the line is in danger of rubbing on the outrigger halyard can I use the gaff handle to move the angler’s line out of the way?
No, IGFA rules state that no one may touch the angler’s line either bodily or with a device.
Okay, but what about if a fish dives hard right behind the boat and the angler’s line is in danger of rubbing on the transom. Can I place a wet towel on the transom to reduce line friction?
Yes, that would be legal as long as you don’t touch the line with the towel. That is, the towel must be placed on the transom before the line comes into contact with it.
IGFA Rule Book: Rules Explained: