Prop shroud

[specialk]

I just was taking care of a kid who feel off the bow of a wakeboard boat (not Tige) when he stood up to change seats, the driver apparently slowed way down and performed a sharp turn, because the skier fell off, the person fell over the side of the boat and has thier arm struck and amputated by the prop.

Though I am an extremely safe driver and do not power turn ect,however there have been many occasions where I had to quick dethrottle due to possible submerged stick/trot line or illusion on water. I let my kids and other sit in the bow as well, with the emphasis on sit, but they occasionally get up to come back to the back. So even though I am very cautious the potential is still there.

I looked online for shrouds for props, all I could find was outboards or in/out.

It would make since, especially since I have bent by prop twice at very very low speeds, that a simple shroud that extended a few inches infront and behind the prop could have prevented.

I know there is some issue with fluid dynamics of the prop, but some websites states it improves the flow, also if you think how a turbine engine works or a ducted fan for the RC flyers of the group, it should not be a contraindication.

Does anybody know of a protective shroud for the prop that may prevent a direct strike to the blades.

If not, seems like a good bit of saftey equipement that would be easy to make. Mounting it would be the only major hangup I see, but seeing that the tracking fins are directly bolted on, may not be that hard of an install.

Thank you for your thoughts and opinions.

[Ewok]

Depending on the speed it could have been the tracking fins that took his arm off. Unless there was a grate over the prop shroud his arm could have gone in the ducted blade area and been amputated there as well. It's a challenging problem, it would be a good research project for a graduate mechanical engineering student to design a safe prop shroud that would minimize the reduction in performance.

Do you know if the driver kept the engine on and in gear when the person went overboard or were they able to shut-off the engine? Sounds like that might be a good boat bold-face to memorize: Passenger Overboard - Engine Cut-Off, unless there is another reason it would be bad to shut-off the engine quickly.

[chadster2]

I'm with you on this one... but life has a way of ending where it is going to end up. I don't mean to get too deep... but things happen.... just remember to treat each person each day like it's your last chance to give them all you have to give... Off topic.... but making everything too safe is not a real safe thing to do... A jet boat doesn't put out a great wake. and I think that's the direction you are going.... I like the idea! another $5000 but I'd look at it if it were for sale...

[talltigeguy]

It would seem to be pretty easy to bolt up a 'cage' of some sort that wraps around the prop. Sort of like the prop guard on the trailer, but instead attache it to the bottom of the boat.

Part of the problem is that the I/O shrouds are planning on a person being cut from the prop from behind. As you are moving forward the prop is literally sucking water and whatever else is in front of it, into the blades. The shroud would have to be pretty stout with multiple metal blades in front to stop it from sucking people into it. Probably would affect handling quite a bit.

It scares me too when I see my kids hopping around in the front, they think I am grumpy when I yell at them that they have to keep 'cheeks on the seats' when the boat is moving. But this sort of thing is the perfect reminder as to why I am that way.

[specialk]

They weren't going fast, just making the the typical, throttle off and sharp turn, I would assume going about 15 or so. The injury, like others I have seen, was when the prop hit them from the side. When the prop runs over someone, it leaves a very distinct multple laceration, in an even manner with it getting progressively deeper or shallower depending on the initial strike. If there was simple shroud, like they have for the I/O where there was nothing directly infront of the prop, just a sheild around, whatever body part is hit would most likely bounce off of it. May break a bone or tear some tissue, but not like the devestation of a prop injury.

Also, for those who have bent thier prop getting the boat on/off, ie if you have the trailer into the water too far, or bending the prop when you go over a log with the engine off, ie me. It would be a big saver there, and also may prevent the sandblasting effect that some boat owners get from shallow water with gravel.

I think a front grill would be ideal, but not necessary, mabye jsut a crossbar.

If anybody knows a contact person at R/D for a boat manufacture, let me know.

Here is something pretty darn close, if not what we need for inboards

http://www.wakeworld.com/forum/showthread.php?t=705773

a simplier version would be

http://www.cabelas.com/cabelas/en/te...080&hasJS=true


Again, all injuries that I have seen the person has been run over, and not sucked directly in, if there is a little shroud to "bounce" them clear, it would be very effective.

[specialk]

Also with the engine off idea, I am not for sure that a person could react fast enough to, or would be distracted by the person falling in ect. Also, I don't know how long it takes for your prop to stop spinning when you turn off the ignition, if it is greater than a 1/10th or so of a second, the person would aready be under and out. I acutually went out and had my wife randomly drop a life jacket AWAY form the boat, to see my reaction time, and we were about 10 yards past the jacket before I could physically process, locate the ignition and turn off the boat, we were going 20mph.

Try it, you will be suprised of the distance traveled in one second.

Last also, I am not trying to be a mamby pamby (Geico commercial with R Lee Ermey) I know their are risk in anything, but if a simple prop gaurd could have save me the cost of the prop it would be worht it, not to mention one 10 y/o kids entire arm above the elbow.

[chadster2]

We had a class today talking about this type of thing. It was for an I/O or an outboard... different type boat but same type problem. (Swift water rescue with powered rubber boat.) I'd bet the solution for an inboard would cause many problems... Like parts flying off or getting hung up rather than just the prop getting bent. I still like the idea!

[chadster2]

I've hit a lot of stuff in the water.... if something was hit it might deform and get into the prop. That;s much different than the prop getting hit. Insurance would cover the mess and (that's better than an arm or leg) but I would have gone through a few covers by now by just hitting junk...