We routinely use my portable cold water Mi-T-M 4000psi 4gpm as a jet boat engine, basically we have a small 20ft wide shallow river that we cross in a small inflatable raft, we then load that up with supplies such as beer and food. Once boat is loaded up we fire up the motor and use a 15degree tip and lower the wand to just above water level, crank up the rpm's and off I go across the stream to our designated chill spot. Roughly 4 trips are made to ferry people across, once we land I throw on a turbo nozzle and blast the surface sandy area free of sticker and other pokey things, "I tried a leaf blower but it created way too much dust, since its hot outside the water from the pressure washer is usually soaked into the sand instantly leaving no muddy mess to walk through. Once done we load everything back into the boat and i carry it all back, and I then wash off everyones shoes off of dirt and sand before they get into their cars. I use a small 12v electric water pump with a motorcycle battery mounted on my washer to suck up the water from the river to supply my pressure washer.
I have done this successfully with 0 problems this summer for a total of perhaps 70+ cross river trips and have yet to spend 4k on a full size jet boat that would only get stuck on every shallow rock or sand bar. Well... if I win perhaps Ill take some photos of our Nile river crossing expeditions.
-Manuel