<br /><br />I am trying to do this while working but based on quick measurements You should throw water up to about 65 feet. But your volume will be fairly low about .25 of a gallon utilizing two cylinders at the same time... If you employ an actuator tube we could get alot more but that could be expensive.... You may be able to make a really cool water balloon gun?????????? The pressure gives me some concern...<br /><br />More to come <br /><br />Just a thought: I can see a problem with a fast approaching PWC and a rider that gets nailed in an unprotected eyeball. Take the speed of the PWC and add it to the speed for your golf-ball-sized water ball
apply that to the eyeball plus loss of vision and multiply by attorney fees and court costs.<br /><br />Also, I dont know if what you want to do is a crime
and I dont know about your state laws, but in California, things that arent firearms are required to be defined as firearms when used in the commission of a crime. That includes pneumatic launched projectiles, including water! There is a mandatory 5-year, no parole prison sentence just for the use of that water cannon in the commission of a crime here. But I dont know if it is actually a crime. The last thing you need is to get tangled up in an otherwise preventable issue. I can just image what would be involved if someone got hurt, and that someone is a friend or relative of someone else in law enforcement
<br /><br />Just things to consider.
<br /><br />To be honest this thing would be terribly cumbersome to construct. But the theory works, and oooohhhhh just the dream of knocking off an inconsiderate jet boy is going to require me to take a cold shower tonight. 
<br />(Well, I can fantasize, can't I?)<br />Disclaimer: Kids don't let your parents try this!
<br /><br />Besides the people on PWC's, skiers, and people that boat get wet. If you see them wearing bathing suits, they could be game.<br /><br />My cannon will probably end up being just a super distance squirt gun. I'll just have a bunch of nozzles like a shower head. <br /><br />Sometimes people who worry about what "What If" so much that life will pass them by.<br /><br />I'm still going for it. You should design it with 4-6" PCV to look like cannon and mount it on the swim step <br />I use the trim on a 90hp OB jet. Nail it real quick and it sends a stream like a fire hose out to about 150 ft! Kids on the beach always like it when they see a 30ft high water stream and the kid in the boat enjoys it too <br /><br />Keep us posted... Hmmm wonder if one could get a tag from the fish & wildlife for PWC's and what would the limit be?? 
