This is what it took to make Game Over, my 711ci Hemi Twin Turbo jet boat, run its fastest pass to date. Watch as I take a grinder to the bottom of my fiberglass boat hull and radically change its shape in search of more speed. The re-shaped keel increased the water volume of water entering the jet drive and also increased the water pressure inside the jet drive. The results was a 15 mph increase in speed after just 1 hour of work on the bottom of the hull.