Actually, you can make your own temporary masthead float. All you need is a ballon or two and some string. A typical ballon has a volume of about one cubic foot, so it will give you 62 pounds force of bouyancy in fresh water, more in salt. In addition, balloons are lighter than tetherballs. This will reduce weight aloft. It's also cheaper.

D. Ho
TheMightyHobie18 1067