I don't have a picture but of all my attempts over the years I like the following the best: Take a piece of 2x4, drill pairs of holes at a 10-15 degree angle, insert dowels, and cover them with pipe insulation.
(You can add additional dowels for PFDs, rope, etc.)
20150219_001 by Alan, on Flickr
How about one on wheels? This one hold 10 on each side.