I read on this forum about the Chainplates failures in older IP's so I inspected mine with a fibre optic inspection scope... Sure enough several of them were very rusty , mostly at the upper weld.
This winter I decided to address this problem before they failed by adding external Chainplates to the outside of the boat.
I did not remove the original internal Chainplates, because none of them had actually failed.
And removing the interior of the boat, grinding out the interior fibreglass and then fibreglassing in new Chainplates, looked like a heck of a mess and a complicated repair.
So I just removed minimal interior cabinetry, and drilled the holes for the Chainplate bolts.
For each Chainplate I exposed one horizontal bar and drilled right out thru the old chainplate crossbar and the fibreglass hull. Then I measured between the existing chainplate crossbars, it was 2.75 inches Center to Center. Then relocating outside I measured up from the first hole and located the hole to drill back in thru the other crossbar in the existing original Stainless Steel chainplate. So, that allowed me to build on the strength of the original chainplates.
For every new chainplate I have two 3/8" Stainless bolts thru the existing horizontal crossbars in the Chainplates. So the new external Chainplates are bolted to two pieces of the old Stainless Steel chainplate .
As well, for each new chainplate I put 2 or 3 bolts right thru the fibreglass hull, and used Aluminium backing plates to distribute the load.
So I now have new external Chainplates bolted to the original glassed in Chainplates, and to the hull.
It was easier and less work then the classic replacing the Chainplates by cutting them out and then fibreglassing in similar but bigger Chainplates, but it was still a challenging project, a lot of work and not for everybody.
Other then the new Chainplates, which I had made locally, I just purchased some high quality drill bits 1/8" to 3/8" , a new corded right angle drive drill, for accessing tight spots and two special grinding discs to polish the new Chainplates, and the existing rub rails.
Here are some photos.
The top photo shows the Aluminium backing plates on the three lower holes / bolts.
And it also shows one of the two new bolts coming thru the original chainplate
Contact me if you want to talk about it.