I have a Skeeter Fish n' Ski that I plan on storing outside this winter due to the unavailability of space in my garage.  The wife says one boat in the garage is enough, and my Nitro takes up the garage.  

So, I want to make a PVC Support system to fit underneath my regular cover that will support the cover, and a loose tarp for the winter months.  

I already have some support poles, but they aren't sturdy enough to hold the weight of the cover and a tarp, so I need some minds more geared towards engineering than my own.  

Here is a pic of the layout of my boat.  Thanks for the help.  

For $20 you can buy a cover support strapping system from BPS that should adequately do what you want it to do.  I bought on years ago and it served me well.  

Shrink wrap it.  It's cheaper than most think for small boats.  The trick is to bring it to a marina that does lots of BIG boats.  They look at yours as a quick side job-low $$

You might try the gray pipe for electrical conduit.  I use it for extra support because it will bend and form an arch so I don't have to make any joints.

Get some PVC that will fit over your fishing seat pedistals (short folding seat type) along with two 90 degree fittings and one Tee. Cut two lengths to the height above the deck that your cover will allow. Install the two pedistals, place the two pieces of pipe over them. Then install the 90 degree fittings on the two pieces. Measure the distance between the two and cut a length of PVC to that length. Then cut that lenght in half. Put those two pieces together with the Tee and place that assembly into the two 90 degree fittings. Then cut a length of PVC to go from the Tee to the floor of the boat. Do all this without glueing any parts together. You can glue some of the parts together later if you want to. What you will have is a frame with center support to handle just about any weight and won't have any sharp edges to damage your cover.