It depends a lot on the wood in question. Ash and white oak can be hard to bend. Red oak bends a bit easier than white. You can wet the stock a bit and then heat it some too. Fir is a lot easier to bend than ash.
You don't need a sixteen foot steamer. Although I did make one once. The Beavertail and even more so the Honky Dory bend most around the front seat location. If you cut full 3/4" inch stock and then wrap it in wet rags over night, and then turn the heat on for a few hours and then, at the last minute point a heat gun at the high bend area you'll be surprised how easy it is, compared to dry bending cold stock.
If you want to dry bend (no moisture no heat) the gunwales 1-3/4" inch by 5/8" or so bends nicely and I've used it many times. I typically cut the 1-3/4" dimension on the table saw and then run the stock flat through a planer a few times, to gnaw it down to a bit less than 3/4" inch. I used red oak many times. Red oak has a bad reputation as a boat building wood because it turns black if left wet for too long. But drift boat gunwales are never (you hope anyway) submerged and you can keep them well soaked in oil. Fir is good because it's strong and light. Mahogany is hard to bend without breaking.