If you have an old inflatable mattress, consisting of several independent sections, it is easy to adapt as life jacket for boating. You will have to sacrifice one of the middle sections, making it T-shaped hole for threading of the head. To fix the other slightly inflated section around the torso using the waist belt and extra lacing.
Recommend to read
THE WING OR SAIL?
The question posed in the title, still have not found a final resolution. The first experiments to replace the traditional sail is a vertical wing, by profiling and design friends of the...
INSTEAD OF LIPSTICK — FERRITE
To match the antenna output stage of a simple Amateur transmitter on the bands 80 and 160 meters are usually used FERROVIAL made on the basis of a unified regulator of the size of the...