I'm not sure from your post if you are using the car's original roof rack or if you have an add-on. Yakima, and possibly Thule, make several options. My reply is specific to Yakima b/c that is the system we have on both of our vehicles (one is a Subaru Outback). First, there is a loading bar that you can add to the rack's supporting towers. It slides out on one side of the car. With our 17 and 18 ft touring kayaks, we can pull out the bar, rest the bow on the bar with the stern on the ground, then with part of the weight of the boat on the bar, move the back of the kayak into the rack. Then, with the stern resting in the rack, move the bow into the rack.

Another, and probably better, option was recently introduced in the last year or so - Yakima's version is called showboat (and at least one other company makes an add-on bar that is similar). The idea is similar to the sliding loading bar above, but instead of being on the side of the car, it slides out over the back of the car. Put the bow on the showboat bar and slide the boat into the rack. The other cool thing about the showboat is that you can move it sideways, depending on how the boat is centered on your car or for loading 2 kayaks. (these options can also be used for canoes.) We do not have the showboat system, but a friend has it and likes it a lot.

My husband has the side sliding bar on his 4Runner b/c that vehicle is so tall. Both of these sliding bar options will work on Subaru's. Since I don't have either sliding bar option on my Outback, I put a piece of carpet or something similar on the back of the roof. Then, with the bow on the carpet, I slide the boat into the rack - definitely the least expensive option!

One other note re: the outback since you did not mention which model year you have: when I traded in my 2000 Outback for my current, 2008 model, I requested information from Subaru about the weight limits for that stupid wing over the back window. The 2000 model did not have a wing and I wanted to make sure that the wing on the 2008 would support the weight of any boats I might rest on it in the future. Their maxmimum weight limit for the wing is 100 lbs, so it should support the weight of your canoe, unless you have the Queen Mary of canoes.