In my case, I noticed some, (not much) give in the salon floor, early on, after purchase of the boat. I solved the problem with some stainless steel stanchions, or supports to the aluminum channel over the engine stringers, to a piece of 1/2 inch plywood on the top, over the engine room tile sound proofing, to spread the load. Works great...see the two attached photos...
Plus, you have something to grab onto, when you go down there in a seaway. Plus, the support on the starboard engine keeps me from running into the spinning alternator...ouch!
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