Will a Z's Drifter handle 2 fishermen @225# and a small motor to get back upsteam? Also,could I increase the bottom width to 48" and both transoms accordingly with 12' side pannels?
Z’s drifter pram is an excellent design for its intended use, and it is a uniquely easy and efficient build. Dave’s a genius at thinking “efficiency” and “practicality.” I don’t recall the certification limitations but I do recall Dave telling me that his home state (PA) will permit a small motor on this boat. Having said that, I do think you will stretch the boat’s capacity as it is with what you propose and therefore, I wouldn’t do it. She’s best suited for the oars with one or two people. And, Yes, if you are willing to take the time, do some modeling you can both lengthen and broaden her a bit, something Dave has thought about. Alternatively, you might look at the 14’ Rapid Robert. It is specifically intended for what you propose, originally designed and built by Tom Kaarhus in the late 1940s. Ray Heater’s Perfect Mac kit is a cool adaptation of this boat (http://raysriverdories.com/driftboat_MckenzieRiverSpecs.html). Plans for the original RR are also available free online (http://home.clara.net/gmatkin/rapidrobert/rapidrobert.htm) and are also in my book.
Listen to Roger. This is not the boat you want. You could use it as a starting point and modify, but by then you will be better served with a Rapid Robert.
I do have the boat registered in PA and it will accept an outboard. We routinely run two fisherman, a cooler of brews and a dog, but thats about it. What make sthe boat nice is its size, capacity and specific purpose- small enoguh to drag far to the river, low sides for easy in and out, and flat water.
You need a boat with a broader purpose.
That said, I've been asked a few times by folks on stretching it, but have not formally kicke doff a project to do so.