Traveling with a full water tank

Honestly, as an old Naval Officer, you are better off towing with either: (a) a full tank, or (b) an empty tank, than with a partly filled tank; because of what we call "the free surface effect". With a full tank, the center of gravity of the water in the tank will stay pretty close to the center of gravity of your trailer. With a partially filled tank, the center of gravity will shift every time you turn or swerve while driving. This could cause unwanted and unstable swaying of your rig as the water sloshes back and forth in the tank.



This "free surface effect" applies equally to black water and grey water tanks. Best to drain all tanks as dry as possible before heading out on the highway.



Anchors Away!!



This makes sense to me, as a railroad conductor on freight trains. When hauling tank cars, we can tell if they aren't quite completely loaded, as the sloshing effect is worse and causes slack action in the train to hit us in the ass end of the locomotive when slowing/stopping.


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There are reports of folks filling their tank(s) and having them 'fall' out.
But... I also bet there are hundreds of folks who fill their tanks and never have a problem. Unless there is a way for you to inspect the tank and the brackets, the only way you will know is to try it.

We have a ss23 Rockwood roo and on mothers day weekend we went camping and filled the water tank at the campground and then went to site less then ja 1/4 mile away and I was lucky that I made it the water tank was just a fraction of a inch away from falling out. its in the shop now
 
I can't imagine the little bit of water we carry (50 / 100 gallons - 415# - 830#) in a tank mounted below the frame is such an issue; at least no more than adding the same amount of dry weight without going over weight limits. If it was mounted on the roof, I could see that would be an issue.

I have never noticed any adverse handling while traveling with the tank at any level. I do see the point of not carrying weight unnecessarily, but I won't drive off with an empty tank then have to find a place to fill it, just to save a 1/10 of a mile per gallon of fuel. If I was that concerned with MPG I would sell it and stay in hotels.

Another issue is whether or not the tank is mounted well; if its weak, fix it. If FR or LCI can't get that right, I know someone that can.
WW
 
Great discussion. Thanks all. I understand the sloshing argument and never thought of that before. Food for thought.


2014 XLR 27 HFS
2006 Ford F450 Dually Diesel
2015 Harley Freewheeler
2004 Harley Road King Custom
 
I'm somewhat in the other camp on the sloshing vs handling issue.

Do any of you worry your vehicle isn't going to handle correctly if you don't keep the fuel tank completely filled at all times?

And don't start your argument with fuel tanks have built in internal baffles.
I've had hundreds of fuel tanks out of vehicles and for many years they had NO baffles at all and the more recent ones with baffles may as well not have them as they are small and almost ineffective.

10,000 gallon tanker cars on the railroad, yes... 30 gallons on a car or trailer... not so much.
 
I'm somewhat in the other camp on the sloshing vs handling issue.

Do any of you worry your vehicle isn't going to handle correctly if you don't keep the fuel tank completely filled at all times?

And don't start your argument with fuel tanks have built in internal baffles.
I've had hundreds of fuel tanks out of vehicles and for many years they had NO baffles at all and the more recent ones with baffles may as well not have them as they are small and almost ineffective.

10,000 gallon tanker cars on the railroad, yes... 30 gallons on a car or trailer... not so much.

X2
 

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