Better way to cover a boat?

What are better ways to cover a boat? I've got a boat cover with one support in the center. It's created a couple of puddles everytime it rains. I've heard of people making their own pvc frames and using cross members from side to side. What are your guys opinions and/or what do you do?

Just curious, I need to do something different.

Here is how I do it. Rope is tied on the trailer tounge, then up and over the front seat, over the top and down the back of the motor, tied in front of the prop, supported in the middle with a piece of PVC and padded everywhere contact is made. Cover is pulled taught with bungies.
I have used the PVC trick and it works fine for a while, but after the summer sun heats it up under the cover, it tends to warp rendering istself useless.
I came up with another solution for a friend of mine. Not sure it would work for most tinboats but here it is anyway. He had pedestal mounts front and back, so I took a 2x4 turned up on edge, drill a hole in each end to accept a short piece of rebar. The trick is to get the holes to meet up with where the pedestals are. Then insert rebar with 2x4 into pedestal riser. Clear as mud? I will try and draw a picture. If you use this method you should round off the ends a little and it wouldn't hurt to run a piece of carpet down the top to keep from wearing on the cover.

I went to the local swimming pool supply store and bought an air pillow it is 3' wide and 12' long and can be inflated to a height f 3' if needed I aid $17 for it. I place it in my boat, but the cover on and use my compressor to fill the pillow. I have been using it for 3 years now with no trouble

Wayne