I would think that part of the reason we use bows rather than any old knot are because the tapes on some life jackets are extremely long. With just a random knot, you'd run the risk of tripping over the tapes on the way to the door but the bows take up some of the excess tape. I couldn't say that that's definitely the reason, but it seems to make sense. Also, if you do have to have to remove the old jacket for a new one as per the SAR helo, the width of the tapes make double bow knots fairly easy to undo, although it'd obviously be trickier when wet. But I may be completely wrong on all of those points!
Would be interested in the answers from those in the know if they ever come back to you!
Last edited by jetset lady; 9th Nov 2012 at 10:25.