The Steamboating Forum

Would exhausting a 3" x 4" engine, operating non-condensing, through a bronze thru-hull fitting above the waterline likely overheat the immediately surrounding region in a GRP hull?

All thoughts appreciated.

What are the proven means of shielding the hull area below the ash pan from fire box heat? All thoughts will be appreciated.

I am new to the forum, and, as requested, am posting a little info about myself. I am a retired engineering professor with a basement full of toys--lathe, milling machine, drill press, band saw table saw, planer, etc. My shortcomings can't be blamed on my tools. I have been a tinkerer all of my life...