Nothing's worse than trying to set up a tarp during a rainstorm while camping.
Running lines to trees while the tarp is flapping like crazy isn't fun.
I have a large Kelty Sunshade. It's expensive. Cost is $169.95 but it has paid off itself in about 10 years of camping and river running.
The Kelty is free-standing and goes up in a snap with three poles. You don't have to run lines to trees or use oars as tarp poles.
It has stayed up in high winds on the Grande Ronde River and downpours in Bear Valley.
It can be adjusted for head room or lower to increase the area to be covered.
Photo by Pete Zimowsky/Idaho Statesman