Are you counting the cabinets in your dimension? I think 3 feet minimum to walk around is needed.

the 18x13 is wall to wall. So 36"-42" from the end of one counter to to the other then?

I'm not sure exactly the size of your kitchen because you say there is an eat in section, and I don't know If the measurements include cabinets. But if you draw a squared off u shape and the long sides are 18 feet and the short side is 13 feet, the distance between the long sides, minus the depth of the base units on both sides is 105". If you subtract the 72" which is the two spaces combined for the walking area around the island, you are left with 33 1/2" for cabinets. Hope that helps.

There seems tobe enough width for an island, but agreed can't tell how your kitchen is currently configured.

The wall to wall dimension is 18x13. The counter top is a "U" at the moment so I guess the "Kitchen side is a "U" shaped kitchen then where the table and chairs are is the other area. All with in the same 18x13 space. So the eating space is about 9x13 and the kitchen space is 9x13. I hope this makes sense. I wanted to redo it and have it all be kitchen and the seating would be on the island.