Average Guy, essentially I took on the same challenge almost 20 years ago (I know that's a mere dust mote in time compared to Gonehuntin' presiding over the fishes and loaves retrieved to hand after multiplying into pile work

). Think I UT'd four times and got fours in all but one attempt - a small farm pond in a southerly clime that had no cover and that the ducks wouldn't stay put on, but that's another story. I then moved into the backyard of a large freshwater impoundment and figured that if the dog were going to be pulling (crippled) ducks and geese out of it, given that the pond, which had no cover and no traffic by fishermen or homeowners, was something like 600 yards in all directions, a duck search wasn't the brightest idea for accomplishing it.
I had started to run AKC retriever hunt tests with another less traditional breed, and just came across the swim-by - and the fun was on! That's for handler and (generally) dog alike, because the swim-by is like pile work with aquatic improv and with more control on your end - you are casting the dog where you want it to go, and if the dog shows any hesitance to follow instructions you can either get in the water with the dog or run to the end of the a swim-by pond (the best are 15 x 30 yards, just long enough for a dog to carry out a longer cast) to meet and greet the dog as it completes the cast by picking up a bumper.
There's more to it than that, of course, but there's also plenty of information on the swim-by to be found online. If you've done the other drills described above, you might already have some familiarity with swim-by. But if not I would send you to an article by Dennis Voigt, one of the best amateur retriever trainers afoot:
http://www.gundogsonline.com/Article/the-swim-by-retriever-training-Page1.htm. The actual "swimming by" the handler in this drill is a major step in handling but that doesn't happen all at once, but is worked toward incrementally over 15 to 20 sessions in a couple weeks' time. Finding a suitable swim-by pond is paramount - I found that out the hard way by having to resort to a Lowe's retention pond and running over rip-rap to keep pace with the dog's progress.
Good luck, hope this helps - or at least gives a little insight into handling a retrieving gundog.
MG