Location Transport

Why do small transporter ships pump water up?

I mean by transporter ships those that guide the big ships in and out of piers. Those little boats that guide the big ships when arriving or leaving a port always eject water. I wonder why?

Public Comments

1. Meaning what?
2. Those are tug boats shooting water out of water cannon up in the air in celebration. Like when they escort a special ship in port.
3. If they pumped the water down, no one would notice.