Whites Cove (Catalina) - revisited

After my 5 days was up at the free anchorage at Newport Beach I decided to head back to Catalina as I had really enjoyed it there. I have been suprised how well the boat systems are working without being connected to any power or water supplies. I have been totally self sufficient for a while now. In fact its been a problem that Im not running the water maker enough and that means extra cleaning of the reverse osmosis system that desalinates the seawater ( read about Osmosis on Wikipedia, its very interesting and explains alot about how salt is such a huge factor in our lives and everything on the planet) As you can tell I have had way too much free time!

I stayed at Catalina for another 8 days. I cant really put my finger on anything specific that I did, but now that kind of thing is worrying me less and less. Actually I did spend some time creating a device to stop the rocking motion of the boat due to swells when at anchor. As I had the time I spent a while looking at some commercial ideas and the science behind what makes the boat rock from side to side, sometimes quite violently if the swell frequency is right. Its mostly to do with the harmonics of the hull and its relationship with the swell hitting it, even if the swell are little ripples they can make it very uncomfortable if they are at the exact frequency that adds to the motion of each movement. There are some commercial product you can buy that are just big dampers that you put over the side of the rail in an attempt to slow down the rocking but they can get quite large and take up a lot of storage space. I read one post from a science major that described the theory and it gave me some ideas to try out. It gave me some work to do for a few days and it could make life at exposed anchorages more comfortable.

I ended up finding the best solution being a heavy duty milk crate (The traditional one full of holes) suspended about a foot below the water from the end of the boom. The boom swung out to side to face the oncoming swells. I normally use 2 anchors (fore and aft) to force the boat to face out to sea into the oncoming swells, but you always get other swells refracting of the cliffs or from other boat traffic passing by. Big tankers, sometimes miles away can be the worst.

Under the milk crate I attached about 20lbs of heavy chain to keep it weighted down. On top, after much experimentation I ended up using a plastic cutting mat (from the galley) that is the same size as the bottom of the milk crate. It is loosely zip tied on one end and then has a bungee cord across the top of it. What this does is to allow the crate to rapidly sink into the water, but as the crate rises the plastic mat closes all the holes in the milk crate like a large valve and has to move a large volume of water to rise. I experimented with different types of valves and larger crate sizes, but found all that was important was to slightly modify the boat harmonics to be asymmetrical to have the best effect. It didn't stop the rocking/flopping of the boat entirely but it reduced it significantly and was very simple. I'm sure all this sounds ridiculous so I will post a picture when I next use it.

 If you have ever seen that famous video of a large bridge falling apart from swaying around in the wind, its the same principle. Watch the youtube video.

My thanks go out to Vons in Avalon (Safeway in SoCal) for letting me use various crates to use in my tests. Avalon was about 20 mins away in the dinghy and I could get intermittent Internet access on my IPhone to look stuff up.