I have been looking for something to work in the above situation for a while. Saw a device made by a company called "Newfound Metals" called a Cleat Chock. think it might work here. 3 sizes, all stainless. Sorry I can't bring the photo over but will try putting the link here:
Charlie, Thanks--It looks as if the line could hit against the edges of the plate, if they lead to one side. Is this a problem?
Harvey--interesting device. I see it has 3/8" studs, 2" long, so you need good access under the deck--and probably best to make a backing plate. Let us know how these work out. The rounded edges should avoid chafe on the line.
You are right, I think it should have a backing plate too. They do come in 3 sizes, and the 8" is the small one. I am looking forward to putting these on the bow to use with a bridle for anchoring or towing if needed. By the time I get that done I may have some pictures too.
Although it is not a TOMCAT, you could be interested to see this ground tackle installation: Bow roller , windlass , cleats on a new "Malcom Tennant" designed Catamaran: