Towboat graffiti artist

I've known a certain person for more than 10 years, maybe closer to 20, and I never knew until recently that we both have family links to the Ohio River. In a message to her, I mentioned a certain towboat that one of her relatives has been on. This was her reply. I took out names and places to protect her identity.

Funny you should mention the (boat). (A few) summers ago I went with (relative) on a (company)  business trip to (state) to a barge building facility and a shipyard where the (boat) was about 1/3 finished. (Relative) had geared me up with steel toed boots, a nomex jumpsuit and a hard hat. We went on the (boat) (still on dry land) and an engineer handed me a hunk if chalk. Said I could write anything I wanted on her walls and they put the insulation over it. What a fun graffiti filled day!!! So, whenever you see the (boat), you'll know all my drawings and name are all over her walls! 

I haven't seen the boat for a few weeks now, but when I do, I'll be wondering what's on those walls under the insulation.

And I'll wonder what hidden secrets other boats out there have.