The question arose as to whether I would need to get the raft registered as a vessel with the Washington State Parks association so I contacted them to find out if that was necessary and how the raft technically qualified.  It turns out that I don't have to register the raft as long as it's human-powered, but once I use mechanical propulsion, I have to get a registration and boater safety classes, and all that hoopla.

The raft does, however, qualify as a vessel which means that I am required to have Coast Guard approved life jackets for everyone on the raft as well as a signaling device (a whistle) and a light should I spend the night on the water so that other boats can see me.  One quick trip to a box store and all three criteria were met.

In finding out the legal requirements for the raft, I also found out that there may be restrictions on using barrels that once contained DMSO.  I've also sent an email to the Washington State Ecology Department to see if they can help figure that out.

We also went to a nearby cedar factory outlet and loaded up on 6' planks that worked nicely as deck boards for the raft.  On a side note, the outlet closes at 1pm on Saturday, and we arrived at 1:30pm not knowing that they had already shut down, but the guys were awesome about it and they let us load up anyway.  A special thanks to Cedar Factory Outlet in Battle Ground, WA!
"Yargh!" says my pirate crew.

By way of construction, all I have left to do is to add in the other two 6' lengths of PVC so that I can lift both sides of the tarp, attach the fish net to the underside for carrying the cargo, and slap together the mini-hammocks that will fill in the open middle sections so that lads can hang out while floating on the water.
 
 
I made a post on the Hammock Forums outlining this project asking for input from folks with more wood-working, boating, and hammocking experience and got a lot of great feedback.

A lot of the input questioned the stability of the raft and whether it would actually fit on the roof of the Jetta.  I had only briefly considered these two components, though fitting on the roof was a critical design factor, I hadn't actually gone through with testing it.

So today I did.  I tested the stability of the raft by trying to tip it over while it was on the lawn and I lifted the frame up on to the roof of the Jetta.  Both tests were successful!
In this photo, I'm holding the frame at an angle while it rests on the roof rack rails.
Mounted and strapped in.  Come game time, I'll flip it so that the deck side is down and the barrels can be lashed in and carried on top.  Additional cargo will go in the back of the car or lashed to the up-turned frame as necessary.
Perched on the edge of the raft, I felt absolutely no tilt or wobble. I know that it will behave differently in water, but I don't have access to water just yet to test that fully, so this is the best I can do with what I've got.
Even leaning to the side, I wasn't able to get the frame to lift up and I'm 245lbs.

Next, the deck!
 
 
Here is the song that I heard on the radio that inspired me to build the raft.
 
 
The vertical hammock posts are built! They slide in to the slots at either end of the frame
I still need 2 more 6ft lengths of PVC so that both sides of the tarp can be up at the same time.