Tank Levels When Towing

Me again. Taking my first long trip in a month and a half so I'm trying to get everything worked out before I leave.

I saw a post earlier when searching for this answer that mentioned water in your fresh tank may cause motion issues; the tanks (most likely) aren't baffled and so the water will slosh around.

Ideally I would like to put a little water in my fresh tank for the first part of my trip so we can use the bathroom. On our stopover I was going to hook up to city water so we can shower quickly, no hair washing or doing dishes. I did not plan on hooking up to the sewer line for just a short stay. It's my least favorite part of camping and its going to be dark and cold both when we arrive that night and leave the next morning. I was going to refill my fresh tank with a bit more water to keep everything even since my black and grey are in the back and fresh is in the front.

Anyway, does anyone see an issue with the sloshing/motion? Surely people who boondock travel with water in their tanks. Should I reformulate this plan?

I leave for FL tomorrow and I just filled my fresh water tank about half way. No need to carry a full tank. We've always traveled with all the tanks partially full. I also have about 5 gallons in my black tank. I want it to slosh around to help breack up any solids which may have stayed behind after the last dump.

It might depend on where your tanks are located.  My fresh water tank is above the TT axles, I travel with the tank about 1/3 -1/2 full and don't notice any motion issues.  Like Rene, I always add about 5 gallons to the black water tank after dumping to get that sloshing working on removing or breaking up any remaining solids. Otherwise, black and grey water tank near empty.

Lowell said:

It might depend on where your tanks are located.  My fresh water tank is above the TT axles, I travel with the tank about 1/3 -1/2 full and don't notice any motion issues.  Like Rene, I always add about 5 gallons to the black water tank after dumping to get that sloshing working on removing or breaking up any remaining solids. Otherwise, black and grey water tank near empty.

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Both grey tanks and the black tank are right on/directly behind the rear axle (bottom is sealed so this is an educated guess based on the drains), the fresh water is under the nose. Thats why I planned on adding some more to the fresh on the second leg of the trip to balance it all out. I would probably end up with about 15-ish gallons across both grey tanks (34 gallons each) after we both shower/brush teeth/wash hands for the night.

The level of the tanks is something I have never worried about. Never had a swishing problem.

I hate to do this to you but have you ever looked at your tank mounts? Mine is old school and pretty tough yet I still reinforced the fresh. My sons FW fresh tank looked like a pregnant whale with how little support there was under it. People have posted about tanks falling out while parked and on the road. I now consider it part of a good inspection and well worth checking. In theory there should be no problem with hauling a full fresh and then hauling that water when it's now in the gray and black....in theory.

https://www.jaycoowners.com/forums/f7/fresh-water-tank-fell-out-12814.html

http://www.forestriverforums.com/forums/f217/fresh-water-tank-fell-out-100622-5.html

http://www.crossroadsowners.com/forums/f14/black-tank-fell-separated-8276.html

http://www.rvforum.net/SMF_forum/index.php?topic=67479.0

QZ said:

I hate to do this to you but have you ever looked at your tank mounts? Mine is old school and pretty tough yet I still reinforced the fresh. My sons FW fresh tank looked like a pregnant whale with how little support there was under it. People have posted about tanks falling out while parked and on the road. I now consider it part of a good inspection and well worth checking. In theory there should be no problem with hauling a full fresh and then hauling that water when it's now in the gray and black....in theory.

https://www.jaycoowners.com/forums/f7/fresh-water-tank-fell-out-12814.html

http://www.forestriverforums.com/forums/f217/fresh-water-tank-fell-out-100622-5.html

http://www.crossroadsowners.com/forums/f14/black-tank-fell-separated-8276.html

http://www.rvforum.net/SMF_forum/index.php?topic=67479.0

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The underneath of the camper is enclosed so I actually have no idea how they are mounted or what holds them in place. I really don't intend to keep any of the tanks totally full though, so I don't see this as being a problem. I do know the tanks coming loose are a possibility, just the same as a tire blow out or the awning unfurling or any of the other lovely mishaps that can happen when hauling a camper.


EDIT: Just realized one of those was for a black tank. Ouch and ew  :-X

Something I learned in truck driving school ... a half full tank creates the most sloshing.  It has to do with the available mass in the tank and the space for it to move.

Less than half full there's less mass.  More than half full there's less space for it to shift.  A full tank or an empty tank won't slosh.

Lou Schneider said:

or an empty tank won't slosh.

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You are right.  ;D   It won't slosh if it's empty. 

rvannie23 said:

The underneath of the camper is enclosed so I actually have no idea how they are mounted or what holds them in place. I really don't intend to keep any of the tanks totally full though, so I don't see this as being a problem. I do know the tanks coming loose are a possibility, just the same as a tire blow out or the awning unfurling or any of the other lovely mishaps that can happen when hauling a camper.


EDIT: Just realized one of those was for a black tank. Ouch and ew  :-X

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Yep, you wont have a problem. I haven't seen a ton of rv tanks but I have never seen a fresh with baffles. I run about 15 or 20 in a 50 gallon fresh tank. The best thing for your black is to have at least 5 or so in it as it will do well at breaking stuff up.

At least in the commercial world, a tank containing potable liquids can't have baffles.  They create too many nooks and crannies where bacteria can breed.

Good point about the bacteria. I really didnt expect the tank to have baffles, it was just something I read on a similar post. My aux fuel tank has baffles and it was one of their main selling points for being different from competitors...so I figured it was sort of a big deal or something.

I'm not super concerned that a little water sloshing is going to pull me off the road or anything, my truck is almost the same weight as the camper after all, but I wanted some reassurance that others traveled with filled tanks as well.

It's one of the many things that get trotted out on internet forums that cause needless worries. Some people have reported losing some water during travel, and rarely you may see a claim that a tank broke loose. Breakage is conceivable, of course, but it's not clear that traveling with water in the tank is the cause.  We've RVed extensively for 20+ years and always carried whatever amount of water was appropriate for our needs at the time. Anywhere from 1/8 tank to full.  If you may need some water enroute, put in what you think you need and don't lose sleep about it.

Lou's advice on quantity is solid.

Long time Forum member Fred Thomas had a Bounder with a long fresh water tank mounted crosswise right across the rear wall.  The location combined with the Bounder's long rear overhang created handling problems if he tried driving with more than a few gallons of water in it.

And we've always started out with a full fresh water tank without any problems.  We usually refill at about the half tank level and we try never to travel with an empty tank.  This reminds me of the "full tank equals less miles per gallon" issue which most of us now agree is a useless argument in most cases.  If you have a full tank and feel it's causing wobbling then use it down and see if it makes a difference.

ArdraF

We always start trips with full fresh water tank. We also start with a couple gallons or so in each holding tank. I also keep a few gallons in each holding tank while parked to (hopefully) prevent seals from dry rot.

Some water in all three with no problems.