The last few years we have loved camping out on various islands in the Columbia River. The best campouts are away from the marine parks and fancy moorage, so we've developed an anchor system over time to keep the boat accessable and safely in deep enough water despite changing tides. Here is our current favorite - an anchored bouy with a bungee rope. Another rope tied to the boat lets us easily pull the boat to shore for access, and when released the bungee pulls the boat back to deeper water.
Here is the bungee system in action - with two boys needing to use the 'facilities' bad! Swim for it, boys!
You can buy bungees to do this anchoring, but I found that ebay has great deals on 100 feet lengths of 3/8" 'shock cord'. With 100feet, I can double the cord up (so it is only 50feet long) to strengthen it, and still get 75 feet of "stretch" to keep the boat deep while still being able to pull it to shore.
Another technique we've used in the past is to hook a large pulley system to the anchor rope's bouy. This worked pretty good to run a long rope from shore, through the pulley, and then back, however the rope often tangled, the pulley got junk in it, and it was much more difficult to pull on the rope. Still worked well, but we are sticking with the bungee. Let us know if it works for you!
