Hi Eddy7592
My deckring was fast turning into aluminium oxide so I decided to replace it. The only available off the shelf option that I could find was the Selden deck ring. It was expensive but it is bombproof and it will still be on the boat when I am long gone. I chose the size two option and it fitted perfectly in the deck with very little work required to set it in place. The internal dimensions of the ring as described in the catalogue are 214mm * 154mm. The external dimension i.e. the hole size required in the deck is 235mm * 180mm. If you require any further dimensions or info I will be glad to help.
Regards Eamonn.