Fastest means of organising preflood from surfaced condition?

[Hoagie27]

Here's how I do it:

-With the neg flooded, open the rear MBT until it reaches 5m^3 then close it. Blow down the rear MBT if needed so that the tank is at 5^3

-Blow out the neg until it is empty.

-Open the forward MBT and watch the gauge until it reaches 10m^3 then close it.

-Top off your air supply.

The end result should be 15m^3 in the forward MBT, 5m^3 in the rear MBT and 0 in the neg.

There is no effect to the boat's top speed or acceleration as long as the combined total of all tanks(MTBs/Trim/Neg) and bilge are under 27m^3

When a dive is called for, open the forward MBT, set the front dive plane full down, leave the rear at 0, then open the rear MBT. Return to the dive planes and arrest the dive by setting both dive planes to 0.

You'll sink like a rock and use 0 air in the process, but make sure your engines have kicked over to electric first though, otherwise you'll flood the engines.

[Fidd]

That's more or less how I'd been taught to do it to start with, but have been playing with other permutations. Thanks to you both for the views

[Lost At Sea]

Originally Posted by Hoagie27

Here's how I do it:

-With the neg flooded, open the rear MBT until it reaches 5m^3 then close it. Blow down the rear MBT if needed so that the tank is at 5^3

-Blow out the neg until it is empty.

-Open the forward MBT and watch the gauge until it reaches 10m^3 then close it.

-Top off your air supply.

The end result should be 15m^3 in the forward MBT, 5m^3 in the rear MBT and 0 in the neg.

There is no effect to the boat's top speed or acceleration as long as the combined total of all tanks(MTBs/Trim/Neg) and bilge are under 27m^3

When a dive is called for, open the forward MBT, set the front dive plane full down, leave the rear at 0, then open the rear MBT. Return to the dive planes and arrest the dive by setting both dive planes to 0.

You'll sink like a rock and use 0 air in the process, but make sure your engines have kicked over to electric first though, otherwise you'll flood the engines.

Will give this a go :-)
However you are referring once to 10m3 in forward MBT and then 15m3 in forward MBT.
Typo or I'm confused somehow?..


Cheers,
Lost

[Hoagie27]

It's not a typo. Wait until the gauge reads 10m^3, then go close it. By the time you walk over and close the forward MBT vents, you will end up with 15m^3 in the tank

[Lost At Sea]

Oh, I see !
Thx for the clarification.

Cheers,
Lost

[Fidd]

Originally Posted by Hoagie27

It's not a typo. Wait until the gauge reads 10m^3, then go close it. By the time you walk over and close the forward MBT vents, you will end up with 15m^3 in the tank

I've been testing this a lot, and it's a neat and easy solution, and more importantly performs well. How viable it is when hull-valves come into play remains to be seen. I'd be interested to hear tester's views on this aspect?

For now, I'd advise moving to close the forward MBT valve at 9m3 rather than ten, as I find myself at typical trim values, having to slightly blow the MBT's in order for the boat to maintain 18kts. Not that am I ever thrilled to be asked to do it.

Thanks to all who contributed!