Float tube

I cannot find the information regarding the size of the inner-tube required for the average float tube, I seem to recall in a dive shop that it was a 20" tube, is this correct. Also I have experience sewing backpacks and am thinking about building my own tube cover, any ideas or suggestions on what should be built into the float tube covers that aren't already on the market. If I'm gonna do it, I'm gonna do it right.

What constitutes a good float depends to some extent on your diving conditions and requirements.

When my wife was a new diver I used a float supported by a full size inner tube. The extra size and buoyancy was useful at the surface. As she gained confidence and no longer required the surface support, I moved to a smaller float with a 12" tube. It is much freindlier in currents, waves and wind.

A heavy mesh bottom is preferrable to a few holes in terms of drainage and a zippered opening on the top is nice to store tools if you do any type of underwater work or to store anything you might find such as an anchor etc, that is too large or heacy to carry on your person.

A center mount such as a D-ring for the flag line is preferable as it tends to make the float easier to tow on the surface than something toward the edge. Webbing around the outside of the tube with a D ring or two is nice to have to provied something to hold onto or clip onto at the surface.

I think 20" is a little big in terms of an innertube for a float. 15"or 16" seems more likely and in the end I don't think it will matter much, a slightly smaller tube will expand to fill the space provided.

If you dive in fast current a torpedo shaped float would be more appropriate and an inner tube used for the bladder. Again it will conform the space availble inside the float.