Not to beat the point to death, but... The case has been made against indefinate hovering, but there has been no case made against the ability to hover for a period of time. Similarily, the point about noise is also sensitve to length of time... if you are only pumping/blowing every 30 minutes, then there are 29 minutes where all stop is a lot quieter than creep.

So I guess the question is - how long ?

If this behaves like a light switch, to me it will simply be irritating, and just as unrealistic as the original behavior. At least default allows you to pretend you have a crew that has a sense of self preservation.

What it comes down to is what you want out of the game. Don't like the humming bird effect? Don't sit still while submerged. Simple as that.

I was just thinking that very thing myself, and I never stop underwater (unless I'm hiding on the bottom).

On the other hand, If you're trying to get absolute realism from your mod (and it is what Teddy is trying to do) then why not go all the way? That said, I'll change my opinion to somewhat agree with greyrider. Though I responded as I did because I percieved his post to wholly derogatory toward the idea of a mod which prevents you from hovering, and I still disagree that you would need speed to keep from listing (all that's required is the proper trim in the tanks), it seems to me that the possibility of the boat taking on a permanent list through damage to one ballast tank could be a pretty cool thing.

I like the idea of realism. But really, I'm too lazy and impatient in my old age for a lot of the stuff. I shoot out ahead of convoys and wait. And really, I could wait until they were like 5,000m away if I wanted to before going under. But meh, I just do it when they're 20,000 if I feel like it.

It had'nt occured to me that a u-boat couldn't hover until this here thread. Interesting. Maybe I'll try it without the hover from now on.

Greyrider wrote:



Hello Grey, after a long time!

About the listing and losing the depth control:

Heinz Schaeffer, the former cmdr of U977 writes in his book U977, page 58 (finish translation): "If the boat would lay down quiet, it would go to the bottom, because in the practice there is not any kind of drifting pictured in the ghost stories about the ships dissapeared forever. Boat has to move on to keep its depth."
In theory it's possible to trim the boat for the certain depth without need to use any speed. But in practice the hole situation is different. Only few more kg's is needed to make the boat to loose the depth. Sometimes it's possible to find a layer of very heavy water. If the boat can be trimmed on that heavy water it's possible to stop the engines and just lay quiet. The heave water is then carrying the boat. BUT, in the conditions of the Atlantic, these kind of layers are: A) not constant and B) usually in the depths out of Uboats normal opdepth. I'm not sure, but on the coast near big rivers (a lot of not salty water coming to the ocean) situation pictured above could be possible and more frequent.

So, that's it. But how about your sonar operations? Have you tried them in the front? ;)

Well, anyway, it's good to see you again!

Greetings,

-Rosie-

That's the plan...

No hovering for me.

1kt seems to be a good min speed to me.

For those who do not know or understand, submarine buoyancy is affected by several different factors including: water temperature, salinity, and depth. Depth in this case is related to hull compressibility and consequently submarine buoyancy rather than water temperature.

Secondly, I see much discussion on the fact that attaining neutral buoyancy (i.e. the humming bird effect) is impossible (not true, but it is nearly impossible so for the purpose of this sim it amounts to the same thing), but no discussion on how this is done. The following is a brief (very brief) outline on how this is done on a 688 class fast attack submarine. Granted, I don't know what the trim and drain system look like on a uboat, but I can imagine, and I'd bet it's not that different from a 688 though many would probably be shocked to hear it.

Now the procedure:

The DOOW establishes an Ahead 1/3 (or 3 knot) trim. This would be the same as an Ahead Slow trim in SH3. This can take from just a few minutes to 30 minutes depending on the skill of the DOOW, the speed at which the boat had been traveling previously, and the time since the last trim compensation. Traveling submerged at high speeds allows the boat to "hide" quite a bit of extra water. This becomes very obvious when you slow down. This isn't nearly the problem for WWII era boats, but it still must be compensated for.

A quick note on trim compensations. The DOOW adjusts the boats trim very frequently in order to compensate for a number of factors that could tend to make the boats buoyancy change. These include: potable water production or consumption, pumping sanitaries, pumping bilges, shooting trash, moving stores, and so on.

The DOOW achieves a 3 knot trim by watching the planesmen once the boat has slowed. If the boat very close to trim, depth can usually be maintained by the inboard station (fairwater planes...the bow planesman on a Uboat). If the boat is way out of trim, the DOOW will have to put an angle on the boat to help maintain depth (an up angle is the boat is heavy for instance, and as is the case in most instances). If still unable to maintain depth with full rise on the planes and a 5 degree angle on the boat, the DOOW will ask the OOD for speed (DOOW use the following progression to help maintain depth: Planes, Angle, Speed).

By observing the amount of plane action necessary to maintain depth, the DOOW can adjust fore/aft trim and trim for neutral buoyancy by taking on water, or pumping off water as the case may be. There are a number of thumbrules the DOOW uses to help in determining the mass of water to move on the boat.

Once a satisfactory 3 knot trim is achieved, and if desired, the DOOW will ask the OOD to slow to 2 knots, where the process starts over, and so on until a bare steerage way neutral trim is achieved. As you can imagine, this is a very time consuming and intensive process. There is a science to this process, but most DOOW in my experience do it by the seat of the pants and rely heavily on experience. In most cases a 3 knot trim is adequate before doing special operations such as periscope depth. In the case of periscope depth, after the DOOW has achieved a 3 knot trim, he will then trim the boat for PD operations.

About the only system I've seen that's really effective at hovering is something like the automated system on Ohio Class SSBNs. It uses a series of sensors to monitor the vertical acceleration, then compensates with the trim pump. Because of the size and complexity of such a system, it's not really very practical for 688s (with a few notable exceptions).

That's just my view based on my time on the pond.

I think 2kts makes it too easy to get away from escorts. You travel twice the distance over the same amount of time then if you were travelling 1kt. And I think 1kt is more realistic as far as what was "sound location speed".

Requirements
#1 1 Knot,fore or aft movement

#2 Helm rating for planemen & Dive Officer,

#3 Rank & experience,of CE & Planesmen,:up: improve stability of boat

Those worried about the sink rates can calm down about the sink rates, by the way. Last I checked, they were nearly negligible - you can stop for a while, in fact, without a serious loss of depth, and still be able to maintain periscope depth in calm weather (but not in storms).

Sounds good.:up:

:rock:

I think what irks me the most is this sense of superiority vibe I get off folks who are realism nazis like this.

This is not indicitive of this post. Just a feeling I get from alot of forums.