What purpose does these serve? just curious. take for instance a 1825 explorer to the 1850 fisherman does it make the boat more stable

They provide one heckuva nice surface for mounting rod holders, downriggers, etc, etc. Plus they make a good serving tray on which to place the lunch and beverages.

One reason I can think of for wider gunnels is they allow the port and starboard storage compartments under the gunnels to have more room for storing gear. I have an Alumacraft TS 185 with wide gunnels and I like them for that reason. Also they make for alot of room to mount rod holders, electronics, etc. From a boat handling standpoint I don't think wide vs narrow gunnels would make much difference but the inboard gunnel walls might add some rigidity to the hull. Wide gunnels do take up some floor space but my rig has a 96" beam and I still have room to rotate the seats 360 degrees without lifting my legs. My 2 cents worth.

b2