Reach RTK for Water Ski and Barefoot Water Ski site setup and surveying

Just reading through many threads trying to improve my rate of achieving FIX Solution status and saw ivereninov comment in thread Rover get fix solution status very difficult! - #8 by TB_RTK about putting the base on a tripod. Why does this have any effect? I ask because I am using a base in exactly that mode, on the ground. I was under the impression that multipath was a huge issue and so my unit with a cake pan metal plane under the antenna and sitting on the ground should not get any multipath I would think? So what is the advantage of putting the base on a tripod?

Also my rover will be used over water. Identical unit to the base. Metal cake pan as the metal ground plane under antenna. In use it will be on a float about 20cm above the surface of the water where I am surveying.