Clarke,
Here are a couple of links to some that I have used from West Marine;
http://www.westmarine.com/webapp/wcs...classNum=13045
and
http://www.westmarine.com/webapp/wcs...classNum=13045
The site above looks to have good prices but these are most likely in stock at the Riverside Store (just past 4 Wheel Parts).
and look at this! I need a few of these;
http://www.westmarine.com/webapp/wcs...classNum=13045