We recently attempted to build a lighter JAE 21, but have not been able to test it since the water got hard here. I wanted to build a light boat but still be able to paint it with PPG Concept single stage car paint even though that adds a few ounces of weight. It came out fairly good at 3.40 lbs, with everything but fuel. We used a GT kit because I really like how easily it goes together with the laser cut and notched parts, but we think the G2 geometry has some advantages. So we cut the bait box off the GT, used the Tommy David mods on the front sponsons, and made the ski a little wider at 1-1/4". I have had very good success with a strutless 0.062" wire drive setup in my 12 JAE, so I set the 21 up with a strutless 0.078" wire drive and ball bearings. Its using small high voltage servos from Pro Modeler and a high voltage Futaba S-Bus receiver. That allows use of a small and light 200 mahr LiPo RX battery with no voltage regulators. A 3.0 lb 21 hydro still eludes us, but we are getting closer! Of course getting it too light may create a whole new set of handling problems on the course.