A shield over the front of the propeller will not allow enough water to propel the boat forward properly. The same goes for changing the waterflow between the pontoons. Do not, I repeat do not change the engineering of any vessel, then you are looking for problems, and create other safety hazards. Would you seal all the windows in your car because a child accidentally fell out of one while the car was doing 60? No, you would make sure a child is in the proper child seat and everyone wears a seatbelt.

In Ontario all operators of a motorized boat including a small electric motor must take a Boaters course and pass a test. This should mandatory everywhere, especially for boaters like yourself. You need to know how a boat propels itself.

Our best safety equipment is our brains. Do not let your children stand in a boat that is motion. Simple as that. In fact unless at wakeless speed I won't let anyone stand in my boat. They are more likely to go overboard.

Tell your kids to stay in their seats, come on man.

an open net-like drape tp fall over the front of the pontoons- not the motor? Glad some adults have kids that always obey .. even when one's back is turned for a second. We are past that stage in rearing children but when I read that tragedy of the child being swept under/between the pontoons I just wondered if some sort of shield could be placed/dropped down in the front of the pontoons that would not impede the water flow but would catch someone/something that fell in the water in front of the boat?

The answer is nothing out there in todays market.

Go and talk someone at your local marina. It might be a million dollar idea.