All 16's should have rotating masts. The mast should have a ball at the base of it that sits into a cup on the front crossbar. This allows it to pivot at this joint. Could you send a picture showing how the base of your mast sits on the boat. Its possible you just need one of the teflon pucks in the cup to lubricate it.
I would check all the standing rigging before taking it out on the water. If you don't know how old it is, everyone on here is going to tell you to replace it all. You don't want to de-mast on the water.
For the righting system, tie a line around the dolphin striker post, coil it up and store it somewhere you can access from the water. If you capsize, throw the end over the upper hull, stand on the lower hull, hold the line and lean back.
For the mast, take it off the boat and put it in the water. Hold it under the water and watch for bubbles. If air is getting out, that means water is getting in and you have a leak. Its nearly impossible to right a boat with a mast full of water. Ask me how I know
