Monday, September 27, 2010

Beefing Up the Roof Rack Extender

From the last post, which was just the feasibility phase, it was apparent that the extender had to be beefed up. When extended, it just did not have the strength and stiffness to hold the weight of the Sunfish. I liked the PVC as the material, but it just needed to be stiffer.
So the solution was to double up the PVC and rivet a metal bar inside the PVC pipe. This made the arrangement much stiffer.
These pictures are out of order, but you can get the concept.

Above is the second PVC clamped to the first. I tried to use the PVC glue but could not get the clamping contact in place before the solvent gave out. I think maybe a construction adhesive or just caulk would work. The [urple primer and orange glue did not work.
Another view of the failed clamping process.

This is a good shot of the concept. Double walled PVC with bar rivetted inside. In order to get the outer PVC to take that shape it needs to be heated. I used a paint stripping heat gun. A torch would also work but may result in burn or too much concentrated heat.

Close-up of the rivets that go through both layers of PVC and into the bar. These will be covered by tape or padding to prevent them from scratching the hull.

Above is the original showing the bar in place and the sliced section to be used to double up the PVC.

This is the heat gun I used. Good even controlled heating. As it heated, I pushed down on the PVC to open it up and applied clamps to hold it in place while it cooled. PVC is fairly bendable when heated but it will scorch. This is one of those well ventilated space activities.

Here is the PVC sliced open on the table saw. The next one I do will not be sliced in half but just at 3/4. This way, I will be able to get some clamping action from the "C" shape of the pipe which might elimnate the need for rivets through the two layers. The "C" shape pluse construction adhesive may work very well for this. The bar will also be necessary for the stiffness.

Friday, September 3, 2010

Roof Rack Mod for Solo Loading Sunfish

One of my original love activities is sailing. My grandparents retired to a cottage near Kilmarnock, Virginia on a small cove off Dymer Creek. Creeks off the Chesapeake can be pretty big. Dymer Creek, where they were, is about 1/2 mile wide and about 3 miles off the Bay. The Bay is very wide there, you cannot see the other side. There were abondoned farm houses, a burned down menhaden factory, a boat yard where they still built wooden workboats and a small island. Basically the best place in the world for a nine year old to be with a boat in the summer.
Grandad loved the dump and one day we brought back a little sailboat. My grandmother, Bee, sewed a sail for it, Grandad put me in it and gave me a big push away from the dock - probably so he could take a nap - and my adventures really began.
So it is pretty easy to see how I came to love the freedom and feeling of sailing.
The problem is that I need to get the Sunfish - my only remaining sailboat - to the water. I have a trailer but it is not reigstered and the cartop would be a lot easier. The sunfish weighs about 150 lbs and loading it solo would result in a broken back, broken boat or broken car. Lifting one end of the boat is fairly easy but there is no way to lift the boat onto the van one end at a time so I came up with this extension for the rack. It lets you lift the boat up onto the van one end at a time.
The rack extension is 1 1/2" PVC pipe with a 90 deg. bend on the end. There is a slot cut into the bottom of the extension that the leg of the roof rack sticks out of. The slot is long enough to allow the extender to slide out a couple feet, enough to catch the boat. The PVC is not stiff enough by itself for the sunfish so you have to do something to stiffen it. I placed a piece of square metal inside the rack that slides out with the PVC. You could use wood stiffeners along the outside of the PVC or even rig up a leg support that goes to the ground.
In the above, you can see the extender bending under the weight of the sunfish.

The above picture is the angle of attack for lifting one end onto the rack.

Once you have the front end up, it is not too hard to lift the back end up and swing the boat onto the roof. I still need to mount the rear rack, but I wanted to test the concept before going forward.

Below is a detail of the PVC with the cut out. I used a rotary zip saw to cut open the PVC.

Below are 2 shots of the roof rack inserted into the PVC extender showing how the leg of the rack sticks out of the extender and the slide range.

To perfect the rack extenders I need to stiffen the PVC. I might do this with maybe 1/2 plywood running along both sides of the extender cut into a shallow "V" to track the shape of the hull. I have to figure out how to attach the "V" without affecting the ability to slide. This same extender concept would be a great way to mount a shade off the side of the van.