Car Floats part 1

I'm not much on watching reality shows on TV, but my wife got me to watch Railroad Alaska. I will have to say it was a pretty interesting show. Parts of the show takes place at a shipping port where railroad cars are delivered to the Alaska Railroad by a car float. This got me thinking, that this would be a good interchange for a model railroad and would be interesting to model. I know that Walther's came out with a sea port set with a car float and apron. ((The apron is an adjustable bridge that connects to the car floats so the railroad cars can be removed form the floats.)) I have found a few online but the prices of them is getting high and if the price of the kit isn't high the shipping for it is ridicules. March 2014 issue of Model Railroader has an article for scratch building a car float, so using some of the dimensions giving in MR I come up with a plan for a car float 3 feet long and 6 inches wide. I made a mock up using foam board that was purchased at the Dollar Mart of how I thought about putting the port on my layout.