Offshore, my gunwale-mounted hardware is by a company called SOS...top of the line, high-grade stainless and utilizes 1 1/8'' poles...strongly recommend them...6+ years and no trace of corrosion or even discoloration...wanted 1st-class mounts (they are there ALL the time), but went w/inexpensive fiberglass telescoping poles as I don't use 'em often...if you are gonna use 'em a lot, get some good ones, probably gonna set you back 2-300 clams...
I'll try to get a closer shot of 'em...It's just aft of the gas-cap in this photo...USE a backing-plate under the gunwale no matter which mfgr you go with... ;)...