So, I thought I'd test out the legendary customer service and called Hutchins. Talked to Gerry who said he'd never heard of this happening before, although it has because there's a mention of it in an old thread on this forum. He said to cut off the flange that was glassed to the transom, grind off the part on the plywood, and reglass it. Then, the new models have a stainless L bracket on top of that, each side, for "extra security". So somewhere along the line it was determined to be a need, after my 1988 was built. I was in Clearwater today, so he said they would make me a set of the brackets used on the new models. Would only take a day or two. Two hours later I get a call saying they are ready, so I picked them up and also saw how they were installed on a new CP27 being built in the shop.
If you see two stainless carriage bolt heads on your transom, you probably have the brackets. If you dont, you should check to make sure whoever laid up mine didn't do yours too! He was amazed the rudder tube did not leak, but I showed him the pics and he said it should be fine, there's no water. Maybe my son was exgagerating when he said how much it was flexing, I only saw it after we wedged it in place and I watched i through the tiller hole and it only maybe moved a half inch each way. The brackets were $56 roughly, By the way the transom has a wood core, so you need to drill a bigger hole, fill it, and drill through the core so it doesn't weep water into the transom core. The only other plywood under the waterline in the boat is the floor of the bilge under the companionway step, where the bilge pump mounts. It's encapsulated but people drill holes through into it to mount bilge pumps, and that will allow water to seep into that plywood, rot it, and eventually into the keel. Ill have to check, because he said they do not screw the bilge pump down, it just sets in there. Mine has been screwed down, alhough I used the same holes and caulked when I replaced the pump.
As far as doing the actual work, Im having the boat hauled next week to drag back up north for the summer, and they can do the repairs in 4-6 hours that same day. I've decided to spring for that so I don't have to crawl down there and grind off the old fiberglass.
Below are a picture of the new brackets, and the amazingly unbent stainless rudder tube.