fresh water capacity - brunnhilde part 3

Since yesterday, there is rapid progress on this project. I have been very doubtful if this is a good project given the pricy tradeoff of the precious storage space. Also can I execute a solution that is in keeping with what Westfalia has done in a well rounded product where everything is painstakely designed and refined?

Before getting further in the fresh water capacity augmentation project I should recap what the original first post I wrote but accidentally deleted due to an auto-save mishap. I tried to ascertain Brunnhilde's fresh water storage capacity. You would think this should be easy, just refer to the owner manual or the marketing material. It would turned out there are multiple inconsistencies in this capacity.


2006 Airstream 3-page boucher - 36 gallons (it would be 4.81 cubic feet; someone at Airstream must be smoking something really good)

2004 Airstream 2-page boucher - 26.4 gallons; this is also suspiciously grossly overstated (it would be 3.48 cubic feet)

2004 Airstream 15-page brochure - 23.8 cubic feet; this seems more probable (3.1 cubic feet)

I just went and retrieve the Westfalia's supplement manual from the glove box and it agrees with the 2004 2-page boucher, at 26.4 gallons (~100 liters). Still someday I would like to make an actual volumetric measurement.

For future reference I took photos of the technical data chapter.

i have been worrying about this robin family on my plum tree; i saw the mother fought back other invading robins and a squirel; i was afraid the chicks might have been eaten; i check the nest and all is well and the last chick has also hatched; the male robin is a dead beat father that has seldom does his part

As I narrowed down the three Todd water storage tank candidate, it becomes quite apparent which is the most suitable one after seeing the 1/4" thick standard duty 13-gallon tank first hand last night at West Marine. Wanting to conduct an accurate check I decided to purchase the tank on the spot after much deliberations.

knowing i may need to bring home the big tank i drove my compact SUV - i used to own a first gen Miata and the Mini feels like an SUV in comparison

i was very surprised to see they have this many different sizes in the store; missing is the 15 gallon one that is my other candidate

While in the store examining the tank, I worked out some design concerns and identified potential solutions.

i was concerned with the strengthening crease lines on the sides of the tank may interferes with the installation of the round access port (marine deck plate with seal); i also carefully checked the exterior dimensions and they are exactly as specified

 90-degree elbow kit - i bought this too since i can always return it if not needed

i can definitely use a 1/2" dia T fitting

1-to-2 diversion valve - may need something like this - though i prefer a more elegant solution

i would need some of this

this 13-gallon tank is a perfect fit - the 24" depth leaves the end of he tank flash with the vertical wet cell partition; while the bigger 15-gallon tank would also fit (protrudes about 1" beyond) it would look odd for a mere 2 gallons additional capacity

this cheap pump can fit through the existing opening but not the Comet VIP series so an access port must be created

Seeing the tank first hand and then bring it home made a huge difference in the design process. As I let the design ideas simmer a bit, in no time everything begin to fall in place. These including the following:

• how to fill this tank
• how to install a submersible pump with its cable and hose
• the arrangement of the vent/overflow hose routing
• how to splice into the existing primary water supply line without tearing the interior apart
• how to selectively consume from the two tanks, or implement a tank-to-tank transfer system
• how to secure the tank
• how to implement a removable auxiliary tank to free up the storage space while keeping the conversion elegant and user friendly
• how to achieve the least cost, least alternation, and elegant execution while achieving the best design and functionality
• as always i aim to implement the enhancement with the least amount of non-reversible modification; and with these, no new holes is something that I always strive to achieve

I have mostly worked out these question in my head. A lot of the details of the actual implementation hinge on my ability to procure some unique parts from overseas. As I think harder I realize a lot of what I need already are in Brunnhilde - from my previous enhancement projects or existing things that can be repurposed and made more useful.

Right now everything hinges on my ability to procure from overseas an obscure German made product that I found. Searching Google only yields 6 million hits with most links to the manufacturer with only one online seller. The online seller is in Kiev (Kyiv), Ukraine! I could not order it online nor I would want to unless it properly process my overseas shipping address and with credit card or Paypal payment. For all I know the business may long been reduced to rubbles, or the owner and staffs are shooting AK47 while I write this.

As a review of the potential down sides of the project, one important consideration is does it affect the road handling of the vehicle?  The added weight of the system when full, will add about 113 pounds slightly behind the rear axle. The CG is at the same height of all existing water storage. This should be non-perceptible unless you check it with slaloms time trial.

With my plan to restore the spare tire to the original rightful place and rid the POS Onan Cummin' generator the project would actually reduce the left weight bias of the James Cook with a slight improve CG, as well as a slight improved in the trailer hitch tongue weight capacity (but won't change the legal limit).

When all completed, this additional 13 gallons plus the 3.96 gallons of self-contained flush water storage in the cassette toilet, the total increase in fresh water capacity would be about 65%.