harnesses

If it's a sheet load problem, I'd go for the legs method Master Nick said. It works a treat on the I 14 kite, which in 20 knots probably has more load on it than your Vortex mainsheet. 

I despair- we give all this advice and it gets ignored. Especially the "hand on until the Dinghy Show and try them on there" bit. Why do we bother?

it wasnt sarcasm, the main on the vortex is no bigger than say on a 700 or musto and they have the same 4:1 purchase on the sheet. Going to the gym is a serious suggestion as an alternative to spending money on changing your boat.

Also, as the thread is called "harnesses" i assume that the idea is that we talk about harnesses and not mainsheets. Forums are essentially a place to share ideas and find information, if someone searches the forum looking for advice on what harness to buy and come across this thread which is largely about something completely different it doesnt help them a lot.

Remember forums are a way to read what others have posted already, it is not always necessary to start a new thread asking a question which has perhaps been asked before.  Although in your case you do have a genuine and perhaps unusual (for this forum) situation with your age.

yh thanks mister nick looks ok carnt wait to try it  also laser193713 'get down the gym'

Or get down the gym!  Back to harnesses, i use a magic marine skiff lite which is an adjustable nappy, most people seem to say they are really uncomfortable but I have never had a problem with it at all.  Just make sure you "arrange" yourself well down below!