Other Explain the waterbox...

[2lick]

Two things had me thinking about this...

Sunday PAFBC pulled me over for and asked if I had straight pipes on my ski. He was really nice, I explained it had a waterbox (thought you have to to be legal and I thought that would put his mined at ease). He didnt know what a waterbox was but took my word for it... as I started to explain it to him I realized I know what it does buy not how, not really at least.

that and... I have this "custom waterbox" that came in my new ski (looks the size of the powerfactor boxes, mounted similarly). The entrance is high and goes through a pipe about halfway down at a 45ish angle. The exit is in the middle, and has a fitting in to spray (the ski had no pissers).

I was planning to cut this custom box down from 11 inches tall to 7 inches and welded the bottom back on. This is so I can strap a fire extinguisher on top of it ans still fit in the hull. Since I don't really know how the waterbox does there job, I see no harm....

Any thoughts?

 

[yamanube]

It is essentially a baffled muffler. Nobody will really know if cutting the box apart will work unless you post some pictures of it, and even then its a crap shoot (if it is in fact a custom made box) weather or not there are even baffles and if there are, if you will have to modify them to get the dimensions you want).

 

[Quinc]

Do they give tickets in PA for straight pipes on a lake?

 

[2lick]

Do they give tickets in PA for straight pipes on a lake?

He was watching me from shore, then when I took a break he came out to talk to me. I had already waved hi twice that day. Honestly, this is my local spot and I cant afford to not be friends with the local PAFBC, they are there every weekend and its a real small spot. He told me it didn't matter what I had or didn't have if its loud he "could" ticket me. He also said he had no intentions of ticketing me, but wanted to give me a heads up. He asked since it is so loud if I didn't mind to play around not in front of the picnic areas. No one complained, but if they do, then its his problem. I had no problem with that, there is a lot of water to ride on. I talked to the guy for a good 15 minutes about a lot of stuff, we exchanged names, he shook my hand said thanks and said he would remember me he liked my ski

 

[Vumad]

Depends on where you are but anything louder than stock may be illegal. A waterbox with no baffels or an am box with less baffeling may be illegal. It depends on the laws and the duchiness of the officer.

The waterbox basically works by forcing the air to travel through the water before exiting the boat. The baffels cause the box to retain water, and the holes in the baffels control the air flow.

The box also causes back pressure, which compliments the exhaust, and interrupts water being pushed backwards through the exhaust on a tail landing, which is why removing the box makes more noise but no more (or less) power.

At least that's the way I understand it.

 

[Quinc]

I doubt it is illegal or all the jet boats would have to run mufflers...

 

[WAB]

Other craft on the water can be loud, but they are usually passing by quickly. With us, its the same annoying high pitched sound on & on & on & on (it only sounds good to us
How far back on the hull side is your exhaust exit?

 

[TheBuzzard]

for all you stoners out there, the waterbox works just like a bong. exhaust gets blown thru water, bubbles up and goes out the exit. its a noise suppressor and an air pollution control device. pollutes the hell out of the water but saves the air. all the stock junk gets factored in on the back pressure, but as soon as you start the mod process, back pressure isnt necessarily required. . aftermarket water boxes/in line silencers do not function exactly like stock junk, which is why they are louder/less back pressure/increase performance if the motor needs less back pressure. loud ass craft on public waterways aint illegal and here in CA, everything is illegal............

 

[Ducky]

for all you stoners out there, the waterbox works just like a bong. exhaust gets blown thru water, bubbles up and goes out the exit. its a noise suppressor and an air pollution control device. pollutes the hell out of the water but saves the air. all the stock junk gets factored in on the back pressure, but as soon as you start the mod process, back pressure isnt necessarily required. . aftermarket water boxes/in line silencers do not function exactly like stock junk, which is why they are louder/less back pressure/increase performance if the motor needs less back pressure. loud ass craft on public waterways aint illegal and here in CA, everything is illegal............

I know have a very good understanding of how a waterbox works...thanks Buzzard!!

 

[Jp79]

He was watching me from shore, then when I took a break he came out to talk to me. I had already waved hi twice that day. Honestly, this is my local spot and I cant afford to not be friends with the local PAFBC, they are there every weekend and its a real small spot. He told me it didn't matter what I had or didn't have if its loud he "could" ticket me. He also said he had no intentions of ticketing me, but wanted to give me a heads up. He asked since it is so loud if I didn't mind to play around not in front of the picnic areas. No one complained, but if they do, then its his problem. I had no problem with that, there is a lot of water to ride on. I talked to the guy for a good 15 minutes about a lot of stuff, we exchanged names, he shook my hand said thanks and said he would remember me he liked my ski

As per the good old Pa water PO PO !
And by reg you just have to have some time of (muffler) in place. There is no stated decibel therefore nothing to ticket you off of. Just be polite and friendly.

 

[makejetskiinggreatagain]

I doubt it is illegal or all the jet boats would have to run mufflers...

Yes but I've noticed rangers get an extra special hard on from harassing jet skiers. My buddy almost wasn't allowed on to the lake monday because his ski had a tiny bit of water in the engine compartment. But another guy with a boat ahead of him had water in his engine compartment and the ranger didn't bat an eye.

 

[CARBONX2]

The exhaust gases do not go through the water unless you idling around and the box has filled up. That is why we fit the Flow-Control valves. At higher revs the gas velocity and heat will vaporise the water and send it straight out. Some design considerations, the larger the box the more noise it muffles, there are usually 2 chambers, usually 2 smaller pipes of different lengths connect the chambers, how the farvarious pipes stick into a chamber, etc

 

[SuperJETT]

The exhaust gases do not go through the water unless you idling around and the box has filled up. That is why we fit the Flow-Control valves. At higher revs the gas velocity and heat will vaporise the water and send it straight out.

^^^^^ this

One of the main purposes is to prevent water from backing up into the exhaust pipe. On a 550 I had, I put a Jetcraft Turbomuff on it which is a straight through design in the nose but since I ran right-side exhaust, occasionally when I shut it off it would suck a slug of water back into the pipe and wet the plugs. After testing a lot, it seemed to be the right-side exhaust coupled with the Turbomuff and a piston port engine and shutting it off with the throttle partially open. A regular waterbox never had that problem.

 

[CARBONX2]

I disagree, the name of Waterbox is just a name that stuck somewhere through the years(like 'Jetski' which is a Kawasaki trademark), most jacketed exhausts dump the cooling water into the waterbox due to cooling, convenience and sound attenuation.
It all has to do with height on the pipes relative to the outside water level. If the outlet on the exhaust is high enough then there is no need to try prevent water flowing back.(look at an oem bilge setup - there is a bend high up in the ski to preventing water flowing into the ski)

 

[Draggingto]

@SpaceCowboy has X-ray shots that he got of some waterboxes

 

[SpaceCowboy]

Xmetal box and H20 designs box

 

[SpaceCowboy]

My thoughts on making one quieter would be to change hole sizes and perhaps maybe more than one baffle plates like a car exhaust muffler


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[CARBONX2]

Some software near the bottom of this page:
http://www.mh-aerotools.de/airfoils/software.htm

 

[keith t]

And some just ooze BRAAPP!!!!!!!!