anti roll tank

[luke86]

Hi,

i'm searching for a tool ( code ) that describe the mathematical modelling of an anti roll tank.

Could anyone of you help me??

Thanks

[jehardiman]

As far as I know there has been no real effort to model anti-roll tanks beyond simplistic pendulum models. The limitation is basicly the same as modeling ship motion except you are an additional level removed with feedback so convergence is an issue, especially with free surface effects for both waves and tank.

Anti-roll tanks are sized based upon desired GM reduction to give suitable damping then are manually tuned for the actual conditions and because motions in waves is stoichastic, you get what you get. They are not reactive to individual wave forces like stablizer fins. For a discussion of how anti roll tanks are modeled see Bhattacharyya, Dynamics of Marine Vehicles, Section 16.7.

[BMcF]

What he said. And then there is the 'problem' associated with the fact that the implementation of roll tanks is done in so many different ways, with completely passive solutions and various degrees of active control from active orifice control all the way through active pumping transfer.

Back in the mid 90's, I was responsible for taking custody of the US Navy's active roll tank research facility - collecting dust in a lab for many years - and setting it up in a privately-owned facility. The apparatus was huge..moving it and setting it up again was not a trivial exercise. The objective was, at that time, to develop accurate models for computer use, since none existed, and to pursue commercial applications and sales of active flume tanks systems (or acquire a company that already did that. our parent corporation was in discussiuons with Interring at the time).

The almost total lack of any potential for economic payback from the 'R&D' effort brought it to a stop long before any data was obtained or models developed.

[FAST FRED]

Instead of an anti roll tank the "flywheel" stabelizers seem to be a good choice.

They are complex and really expensive.

Perhaps some one has done a re design to make it usefull at less than $50,000 A SHOT?

FF

[dskira]

Yes they had extensive research on anti roll tank.
Fiedship to name one make a very thourough research over a long period of time.
I did myself also.
But my theory is more simple, if you don't like roll, you don't like going boating.
The nature of a boat is at one moment it will roll.
Spending several hunder thousand $ on active or passive anti roll devise is pointless.
It is going against the nature of the beast.
Spend money on a better design and better construction.

My two cents
Daniel

[FAST FRED]

Spending several hunder thousand $ on active or passive anti roll devise is pointless.

Flopper stoppers do quite well and are cheap to install and maintain.

With proper design they will also work at anchor (somewhat) ,install them for a grand or two.

FF

[BMcF]

Spending several hunder thousand $ on active or passive anti roll devise is pointless.

Thank goodness that viewpoint is not pervasive. If it were not, there would not be a 40 million USD annual turnover in roll stabilization systems worldwide.