Water Ballast Design Challenge...

[Polarity]

Now I know you all like a challenge so here it is!...

My new (well 1990) 50ft singlehanded aluminium race boat has water ballast in 4 tanks. There are 2 through hulls, an engine pump, a hand pump and a maze of pipes and valves.

What's the simplest plumbing solution using the least number of valves, least amount of pipes and the least amount of space, to be able to:
Fill any one tank.
Pump between fwd and aft tanks
Pump between port and stbd tanks
Gravity drain between port and stbd
Empty tanks
Have either ballast pump as an emergency bilge pump

Combined with this I would like to use electrovalves or springloaded, string+cleat operated gatevalves for at least the gravity feed (ie tacking) so that impacts the layout as well.

Here is an example by VGYD design http://www.vgyd.com/article_5_ballast_2.html

I have designed a layout - but physically I think it will be too big, I'll dump it into Rhino and post in a while...

So any ideas ...

Paul

[Polarity]

Ok here is my idea Version 1. I have not drawn vents or intake seacock, The gates could be replaced with 3 way L valves, but I have left as gates for clarity.

All the valves are below tank level
Example (assuming all valves closed to start and re-closed after operation)
- To fill stbd aft tank, open 4 and 5, use either pump
- To gravity fill from stbd aft to port aft open valves 4 and 2
- To pump from stbd aft to port aft open 3 and 2, use either pump
- To dump port aft open 2 and 6

Comments and better ways please!

[Tad]

Paul;

My first thought was, "manifold".

Have you seen the system diagram in Eric Tabarly's book, Ocean Racing? He had four tanks, but only one pump, and a total of 7 valves. If you eliminate the need to pump between tanks, it will also eliminate one half of the valves in your system.

Tabarly used two crossover tubes beteen the P & S tanks, with a fore & aft tube that was the maifold, it had intakes and outlet valved off it.

I'm sure someone will have something better.

Tad

[Polarity]

Thanks Tad
That sounds similar to what I am drawing right now...
If I can empty an individual tank then I effectively can "pump between" if you see what I mean... Working on it..

[Tad]

I guess I was wondering why you would want to pump between tanks? Looking for "dense" water?

[Polarity]

Tad
I was thinking for fore and aft trim, but also for tacking then pumping up. - also for the mental excersise

V 2
This one is self explanatory, exept to say that the 3 way valves are all T type.

Pro's
- seperate in and out means appropriate direction for the scoops
- if she's trimmed say full aft and half fwd on a stbd tack, I can preserve that trim on the opposite tack.
- fewer valves

Cons
- no pump between tanks, its dump or pump for trim or pre-tack
- cant remotely operate the 3 way valves

Comments...

[Polarity]

Tad, like this:

[Tad]

Paul,

Yes, the bottom one is that of Pen Duick V, circa 1968!

[Polarity]

Originally posted by Tad
Paul,

Yes, the bottom one is that of Pen Duick V, circa 1968!

I guess basic pipe and valve technology has not changed much!

[Tad]

Paul,

I am afraid I think Mr. Taberly was just a very long way out in front, in much more than just the sailing part.

Take care, Tad

[Tad]

Paul;

I found some info on a Whitbread 60 system, which allows pumping both ways. It's a bit diferent in that they used 3 tanks each side, the limit was 5508 pounds of water. The forward tank held 49%, aft outboard had 21%, aft inboard 30%. They developed a series of target ballast loads for particular TWS and courses, interesting.

Plumbing system;

Main manifold; athwartships fiberglass construction, main 4" transfer valve midships. Three 2" inlet/outlets each side from the tanks.

Just aft of the main mainfold is another thwartships 3" tube, 3" inlet valve in port end and 3" outlet in the starboard end. Pump on centerline, inlet port, out starboard.

Four 3" tubes run fore & aft between the main mainfold and the pump crossover. Each has a valve. Two of these connect the port side of the main maifold to the port and starboard side of the pump (that would be the in and out) and two connect the starboard side to the positive and negitive sides of the pump.

So there are three inlets to the pump and three outlets. But you have two seacocks, four directional valves, one main crossover valve, and six tank valves.

Tad

[dionysis]

Here is another one polarity. I'm sorry but I don't know where I got it from.

water ballast schematic:

[Polarity]

Thanks Dionysis. Not so keen on that set up as there is no easy gravity option.

Thanks Tad I'll try and work that one out!

PAul

[dionysis]

I think these systems are right - correct me if I am wrong:

Scenario 1: Forward valve can divert water athwartships, via gravity only or aft via pump or gravity to tank 3 say. Aft valve vice versa. Central pump can pump in or out to any tank using valve combinations.

Scenario 2: Change forward and aft valves for pump/valve combinations; change central pump for a valve, and you can do what you like, both gravity and pump wise.

Stick a valve on the inlet/outlet pipe and you can include the bilge.



cheers

[Polarity]

Umm I'm confused.I think I might have missed something in the diagram. How do you pump from 1 to 3? How would you pump up after tacking ? How do you dump water. I'm assuming it wont flow through the pump...