Tank content calculation software

Fresh/Waste Water Systems, Watermakers, HVAC, Refrigeration...
User avatar
Michel
Posts: 546
Joined: Sun Dec 07, 2008 5:48 am
Location: Zaanstad, the Netherlands, EU

Tank content calculation software

Post by Michel »

I'm investigating tank monitoring systems at the moment. In the course of that, I found a very nice piece of software that helps you calculate the contents of odd shaped tanks. And more, it calculates the relation of the liquid level in the tank to the volume of the liquid in the tank for heigth levels 20%, 40%, 60% and 80%. The software is made by BEP Marine, a company from New Zealand that produces lots of marine electrics products. They are widely available in the NL's.

http://www.bepmarine.com/Tank-Sender-So ... s-327.html

TS1 programming software is what you need to download.
Michel Capel, Freedom 44 #4 1981 'Alabama Queen', NED8188, cat ketch with wishbones, home port Enkhuizen, the Netherlands, 52*42.238'N 005*18.154'E.

User avatar
GeoffSchultz
Posts: 1135
Joined: Thu Dec 04, 2008 8:39 am
Location: BlueJacket: Guatemala
Contact:

Re: Tank content calculation software

Post by GeoffSchultz »

I use a much more complex system... :) I start with an empty tank and pull into a dock with a metered gauge. I then stand at the fuel/water gauge and have Sue start filling the tank. At 1/4, 1/2, 3/4 and full I have her record the readings. I then stick a label next to the gauge with the amount in the tank at each level. This does away with any calibration effects from the measuring level and is just plain simple.

-- Geoff
BlueJacket
1997 Freedom 40/40
http://www.GeoffSchultz.org

User avatar
Michel
Posts: 546
Joined: Sun Dec 07, 2008 5:48 am
Location: Zaanstad, the Netherlands, EU

Re: Tank content calculation software

Post by Michel »

We don't have metered water connections here, at least I've never met one. For fuel, I do the same drill as you do, only I seldom fill up the tank, because then it sits too long.
Michel Capel, Freedom 44 #4 1981 'Alabama Queen', NED8188, cat ketch with wishbones, home port Enkhuizen, the Netherlands, 52*42.238'N 005*18.154'E.

User avatar
THATBOATGUY
Posts: 574
Joined: Thu Dec 04, 2008 9:50 am
Location: F40 CC CK Maryland
Contact:

Re: Tank content calculation software

Post by THATBOATGUY »

Michel wrote:We don't have metered water connections here, at least I've never met one. For fuel, I do the same drill as you do, only I seldom fill up the tank, because then it sits too long.
Hey Michel,

We have terrible problems with condensation in high humidity parts of the country here. We try and keep our fuel tanks full at all times. The diesel actually keeps surprisingly well for years and if I'm not mistaken your diesel over there might even start out at a higher cetane rating than ours (not too sure about that one). The old Perkins are not so picky as their newer higher compression cousins.

Thanks for the software lead. I'm going to be making some odd shaped tanks soon. One is to replace the swiss cheese one and a new one to go in near it. That software will give me a good idea of how much tankage I want to add.

George
George and Kerri Huffman S/V Marquesa Freedom 40 CC CK Sail MarquesaImage

User avatar
Michel
Posts: 546
Joined: Sun Dec 07, 2008 5:48 am
Location: Zaanstad, the Netherlands, EU

Re: Tank content calculation software

Post by Michel »

The story of condensation in diesel tanks goes around here too. But I've never found a drop of water in the drain well of any of my boats (all Freedoms). Wit the sandwich hull, the headliner and the diesel tank sitting in the middle of the boat away from the hull and inside a wooden box with airspace all around the tank, condensation won't be too bad. Only on the inside of my deckhatches there is condensation.
Michel Capel, Freedom 44 #4 1981 'Alabama Queen', NED8188, cat ketch with wishbones, home port Enkhuizen, the Netherlands, 52*42.238'N 005*18.154'E.

User avatar
GeoffSchultz
Posts: 1135
Joined: Thu Dec 04, 2008 8:39 am
Location: BlueJacket: Guatemala
Contact:

Re: Tank content calculation software

Post by GeoffSchultz »

I'd fill a container of known volume and then calculate [liters/gallons] per minute. Record the time at which it gauge reads 1/4, 1/2, 3/4 and full, and then use this to calculate actual volumes. My diesel tank is incredibly non-linear. However, I'd guess that we're talking about a water tank here, as I've always seen well metered fuel dispensers! :lol:

-- Geoff
BlueJacket
1997 Freedom 40/40
http://www.GeoffSchultz.org

katorpus
Posts: 146
Joined: Thu Dec 04, 2008 10:51 pm

Re: Tank content calculation software

Post by katorpus »

Michel

Unless you have some way of de-humidifying the air that's drawn into the tank through the vents, you'll ALWAYS get condensation in a diesel tank...for the following reasons.

The fuel that leaves the tank in the inlet line to the filters and thence the engine is not all used by the engine. That which goes back into the tank (via the return line) is warmed, at least slightly. The warmer the fuel, the more it is "expanded" in the tank itself, and the warmer the air space (in the tank) above the fuel.

The moisture that is driven out of the air in the air space by this process falls to the bottom of the tank. The (cooler, more moisture laden) air that replaces the burned fuel flows in through the vent line. As the fuel in the tank cools (and shrinks), more of this air flows in through the vent line. No matter how well the tank is insulated, condensation occurs on the inner walls of the tank when the cooler outside air meets the warm "top surface" of the fuel and the tank walls which have been warmed by the fuel. It also occurs when warm, moisture laden air meets cold fuel & tank walls.

As the outside air temperature rises and falls, the air in the space above the fuel "breathes" in and out, and more moisture gets into the tank. Any differential in air & fuel temperature is going to result in moisture migration, but the moisture in the tank (that's settled under the fuel) is never going to migrate out.

Less air space = less moisture laden air within the tank = less condensation within the tank...every time.

If your tank consisted of a collapsing bladder (closed, unvented system), you'd never get any water in the fuel that wasn't there when you bought it.

All of this holds true only when there's humidity IN the air. As the outside air temperature approaches freezing, there is less humidity (and thus less water available to condense). It may be that your winter air temperature is such that you aren't getting much of this in winter. It's at it's worst when it's foggy outside.

User avatar
Michel
Posts: 546
Joined: Sun Dec 07, 2008 5:48 am
Location: Zaanstad, the Netherlands, EU

Re: Tank content calculation software

Post by Michel »

John,

Of course you're totally right with the theory, but nonetheless I never found water in the drain well of the diesel tank or in the Racor separators. So there is probably not much condensation water in my tank.
Michel Capel, Freedom 44 #4 1981 'Alabama Queen', NED8188, cat ketch with wishbones, home port Enkhuizen, the Netherlands, 52*42.238'N 005*18.154'E.

User avatar
THATBOATGUY
Posts: 574
Joined: Thu Dec 04, 2008 9:50 am
Location: F40 CC CK Maryland
Contact:

Re: Tank content calculation software

Post by THATBOATGUY »

Our Freedom is the first boat I ever saw where the vent line for the tank has a shut off valve. Such a sensible addition and I never thought of it before.

George
George and Kerri Huffman S/V Marquesa Freedom 40 CC CK Sail MarquesaImage

katorpus
Posts: 146
Joined: Thu Dec 04, 2008 10:51 pm

Re: Tank content calculation software

Post by katorpus »

Awww George

That shutoff in the vent line is just there in case you find yourself in conditions where a rollover is imminent...

(tongue firmly in cheek)

Actually, it'd probably be a good idea to shut it when filling the tank (to prevent foamed fuel from overflowing...or liquid fuel if you get really lunchy and fill the tank up to the level of the deck fill).

If you shut it when you went off and left the boat, then a temperature rise would pressurize the tank...which I can't see as being very good for anything...especially since the weak point in the system is probably the hose-clamped connection between the fill hose and the tank itself...one of the places that you don't want to discover a leak when off on a trip...

Another weak spot is likely to be the o-ring in the deck fill...and if that "pops out", the next rain is gonna put a whole lot more water in the tank than whatever condensation that might have occurred would.

But then again, that pressurized fuel might "only" find its way through the filters, past the fuel pump, through the injectors, and simply flood a cylinder or two. No worries there, it'd probably just run past the rings (by the time you got back and restarted the boat) and just end up diluting the crankcase oil a litte (tongue in cheek again).

Post Reply