As Galantin explained in "Take Her Deep!", it was only a small hindrence, and was usually consumed well before reaching any area of enemy activity. As the fuel was used, sea water would replace it, since the fuel wouldn't mix and would float on top anyway. So it didn't really do anything but make the boat sit a little lower, and any fuel inefficency caused by the increased drag from that would be well compensated by the extra fuel that was available that originally caused it. And dive times would actually be slower at first because the oil weighs less, thus less ballast, but it would soon be neglible as it became more and more seawater in the tanks.

Galantin did mention that once the extra fuel in the ballast tanks were consumed, the sub would repeatedly dive and surface, to flush out any trace amounts of oil that would leave a "tell-tale slick" when diving in a combat situation. So in that effect, it effect combat operations. No reason to add that into game though, before adding in diving at least once a day to adjust trim in the ballast tanks. That's more of a day-to-day thing missing than a one-time flushing.

After doing some looking around, I would say that as long as the fuel capacity we use includes the fuel/ballast tank capacity included in the calculation, then 12KNM @ 10.95kts is fine IMHO.

Frank "Torpex" Kulick
Subsim Staff :cool:

I am sure that the tank was isolated from the others. A simple valve line up is all would be needed.

Frank "Torpex" Kulick
Subsim Staff :cool:

Saltwater mixed into the diesel even in tiney amounts would absolutly wreck the engine. Ive seen a 750 HP diesel generator that inhaled some rain water and ended up siezing the engine. The cylinder walls looked like they were scrubbed with 80 grit sandpaper.

There is a gizmo called a fuel / water seperator on the fuel feed lines of the engines to try to avoid this catastrophie. In the above example generator the water was sucked through the wall vents, through the air filter, and into the engine. (the mechaincal engineer had undersized the intake louveres and there was too much air velocity literally sucking rain into the room). I imagine that air intakes for a subs engine has some sort of way of avoiding that.

I belive the ballast tanks and fuel tanks had no interaction with one another.

That being said a full fuel tank would most likely help to dive a tad faster but then again the ballast tanks would have to be ... uhh... emptier to keep the ship afloat.

It has been known that at least in game that if the 'ballast tanks' are partially filled from either running decks awash or a recent dive the ship dives faster.

Is the above some kind of cruel pun?

All kidding aside, great thread and great info.

Mylander

From another post recently apperantly there was a series of several tanks between the "open ocean fuel tanks" to the actual engines. They apperantly scrubbed the fuel oil real well before the engines to remove the damaging water.

US Subs had what was called a clean fuel oil tank, and in fact even modern submarines have a similar setup with diesel on top and seawater on bottom. No high tech gizmo here just a simple seperator tank. So, not blasting you, but there is more than one reference in the books about this fuel/ballast tank. It did exist and was used for fuel & once empty, ballast tank.

Frank "Torpex" Kulick
Subsim Staff :cool:

Amazing... although it makes sense because the oil would 'float' above the seawater. I guess they pull the fuel off the top of the tank.

Probably have some damn good fuel/water seperators. I can imagine that in rough conditions the two might mix up to some degree.

I can see filling the 'empty' tank with sea water to keep things balanced too makes sense.

Very nice fuel walk-through. Thanks for the effort.

I was just wondering in the .sim file of the sub, distance is shown as "miles". Now 1 nautical mile = 1.15 mile so does that mean for example in the .sim file lets say for the Gato class, 11,800 miles should in fact read 11,800 nautical miles therefore the setting should be 13,570 in the Gato.sim file :hmm:

Just wondering.

Pretty much all "miles" in game should be "nautical miles". It's a good eye and an obvious possibility. The only statute miles should be given in terms of weather visibility which the game doesn't do.

Even though they did it then & we do it now, and I know how it works...it still amazes me how well it works. :rotfl:

On the nuke boats I was on, we had a waste oil collection tank that the bilges would get pumped to. It has a mixture of seawater & oil leaks from the bilges. We could pump it after so many hours of being pumped into, to allow it to seperate. We'd pump just the seawater out at sea, and in port the waste oil to a tanker on the pier.

Frank "Torpex" Kulick
Subsim Staff :cool:

Nice home experiment
 

Try the following:

1) Get a glass or cup that you can see through so you can observe the effect.
2) Poor some salad or olive oil in the glass
3) Add some water
4) Observe the effect
5) Stir the mixture with a spoon
6) Observe how long it takes for the oil and water to be separated again
7) Poor the olive or salad oil back into the bottle
8) Drink the water

Have fun! :know:

I guess, what I am wondering is what is the best speed to use from and too area in different boats, using only the patched game and TM 1.4.

Now, how lazy is that?

not sure if that has been already said.

There is always an optimum speed for every engine, so called "cruising speed". Cruising speed slightly differs but it seems to be between 10 and 11 knots for most boats. Try setting 10,5 knots and ask for maximum range. You can go about 20% further then at a speed of 8 knots (2/3).

I always try to go on cruising speed over large distances. And then switch to slower speeds when patrolling. Thats the best way to save fuel.