So happy with the submarine behavior...

[Mau]

....movements. i mean the way they act when we are changing depths.
Since 1.03, I am playing just with the OHP. So yesterday I tried the 688i and I saw the change from 1.01.

It is more acting like an airplane. Is it supposed to be that way. I mean it is possible that to play with ballasts is not a perfect science too and with even a skill diving officer it would not go directly to the depth we asked in a very quick way. Am I right.

Is the game is modeled let say "OK" about that?

What about the Mod? Is it changing the this compared to the stock one?

[Slammr]

If I recall correctly, submarines do indeed move like airplanes insofar as bank, pitch, and roll are concerned. :)

[Yskonyn]

That's indeed the case. Air and water are similar in many ways as far as movement goes.
You can more or less see the dive planes of a submarine as the elevator on an aircraft. Both a submarine and an aircraft have a rudder for turning, though in an aircraft the actual use of the rudder is not to make the turn (as in a sub), but to coordinate the turn (curious now as how a sub keeps itself from rolling to a side in a turn).

See? Very similar all in all.
Navigation is also handled quite similar.

[LuftWolf]

What about the Mod? Is it changing the this compared to the stock one?

LWAMI doesn't change the diving behavior, this is hardcoded in the interface, out of our reach. :)

[Mau]

Ok great,

so I'm guessing then that people are happy with it.
We just have to be careful when driving the sub, which I think is a good thing.
It then feel more like a simulator!

Luftwolf, looking at the spped decrease of a sub on a hard (30 deg) turn. The boat is losing just 5 to 6 knots.
I would love to see the OHP doing the same thing (and not going all the time as low as 9 knots)
I know you have increased the diameter for the screw and the acceleration is a lot better and its keeping its speed a lot better.
However, would it help to diminish the effect of the rudder on the OHP?
I would think that is the parameter that affect the most that so big reduction of speed.

Speed is life!!!!

[LuftWolf]

The problem is the setting of the turn radius and/or rudder efficiency.

The rudder efficiency I can't change, and changing the turn radius breaks the AI, so we have to wait for SCS to address this one.

[Bubblehead Nuke]

(curious now as how a sub keeps itself from rolling to a side in a turn).


It has to do with the center of bouyancy being above the center of gravity. When submerged and in proper trim that is a HUGE 'righting force' that keeps the hull upright. A submarine is at its most unstable period when it is diving. If I remember correctly a 688 gets down to about 3 feet of difference at one point when first submerging and that is why they want to get down to PD fast on the dive. Anyone who has served on one can remember that about halfway through the dive the hull 'wallows' and seems to take a abeam sea rather badly. They always want to dive into or away from the wave movement if possible to lessen this effect.

Someone here asked about turning radius and how it is determined. It is rather complex but I will try to remember what one VERY enlighted LTjg on my boat taught me.

Pardon the crudeness of this, but it was shown me with drawings and I am going from 15 year old memories here.

There is a center of mass on the boat and the hull basically pivots on that point in all three axis. In nuke boats that mass would more than likely be the reactor plant and subsequent shielding. They are by far the single heaviest item in the hull. You have to measure the turning radius as a function of the distance from that center to the force that is causing the change in direction (the rudder). The same is true for the stern and fairwater/bow planes. The father away they are from the pivot point the GREATER force they will provide in a direction change for a given amount of exerted force.

Thus larger and more massive boats may well have a smaller turning radius. It all has to do on where the center of mass is that they are turning on. Also, the sterns swings out and the bow moves in the oposite direction, again, with someplace on the hull the pivot point. If the center of mass if NOT in the middle of the hull, IE father forward, then the turning raduis will be smaller as measured at the bow.

I hope this is not too confusing. It is a complex set of mathmatics and I had the pleasure of learning from someone who was working on his OOD quals and had all the actual number and drawings to work with. It was fascinating stuff at the time.

[TopTorp '92]

(curious now as how a sub keeps itself from rolling to a side in a turn).


It has to do with the center of bouyancy being above the center of gravity. When submerged and in proper trim that is a HUGE 'righting force' that keeps the hull upright. A submarine is at its most unstable period when it is diving. If I remember correctly a 688 gets down to about 3 feet of difference at one point when first submerging and that is why they want to get down to PD fast on the dive. Anyone who has served on one can remember that about halfway through the dive the hull 'wallows' and seems to take a abeam sea rather badly. They always want to dive into or away from the wave movement if possible to lessen this effect.

Someone here asked about turning radius and how it is determined. It is rather complex but I will try to remember what one VERY enlighted LTjg on my boat taught me.

Pardon the crudeness of this, but it was shown me with drawings and I am going from 15 year old memories here.

There is a center of mass on the boat and the hull basically pivots on that point in all three axis. In nuke boats that mass would more than likely be the reactor plant and subsequent shielding. They are by far the single heaviest item in the hull. You have to measure the turning radius as a function of the distance from that center to the force that is causing the change in direction (the rudder). The same is true for the stern and fairwater/bow planes. The father away they are from the pivot point the GREATER force they will provide in a direction change for a given amount of exerted force.

Thus larger and more massive boats may well have a smaller turning radius. It all has to do on where the center of mass is that they are turning on. Also, the sterns swings out and the bow moves in the oposite direction, again, with someplace on the hull the pivot point. If the center of mass if NOT in the middle of the hull, IE father forward, then the turning raduis will be smaller as measured at the bow.

I hope this is not too confusing. It is a complex set of mathmatics and I had the pleasure of learning from someone who was working on his OOD quals and had all the actual number and drawings to work with. It was fascinating stuff at the time.

That's a great explanation Bubblehead! I learned something here.

So, suppose that at the end of the patrol when all or most of the food has been eaten and the TDU weights flushed through the TDU, what would happen to the turn radius? Doesn't all this weight shifting change the relationship between the CB and CG?

Also, suppose the ship fired its torpedos and cruise missiles. Wouldn't that too change CB & CG?

Finally, what if the ship travels from one ocean to another? For example, the ship travels from the Med to the Red Sea. Does the change in salinity affect the CB & CG and therefore the trn radius?

Thanks,
Top Torp

[GunnersMate]

I especially love how the boat takes a 30o down angle when coming to periscope depth! And how a hard rudder order at flank results in a jammed dive! :-? :roll:

[Bubblehead Nuke]

That's a great explanation Bubblehead! I learned something here.

So, suppose that at the end of the patrol when all or most of the food has been eaten and the TDU weights flushed through the TDU, what would happen to the turn radius? Doesn't all this weight shifting change the relationship between the CB and CG?

Hard de har har. Come on now. When we do that 120 food loadout the trim of the ship hardly changes. We have no room aft, the crews quarters are #10 cans deep, the command passageway is stuffed to the gills, food is EVERYWHERE. A lot of things yes. TONS and TONS?? No. As you eat the consumables and shoot the TDU's you just add more water to the trim tanks to maintain your trim. Compared to the bulk of the sub and the heavy non-movable items, it is really not much to matter. TDU wieghts are not that heavy and we carried OVERKILL amounts of them. Did we ever run out?? Not that I remembered. Also, in my multiple times at cranking I had the pleasure of asking the mess chief (may his red hair never fade) about how we loaded things aft because it made getting to the outboard chiller plants a PAIN and he said they actually loaded food and consumables in the boat in such as way as to eat thier way to the equipment and fairly equally eat fore and aft. Guess there was more to being a cook than making those HORRID rehydrated eggs eatible.

Also, suppose the ship fired its torpedos and cruise missiles. Wouldn't that too change CB & CG?

Refering to the VLS here as well? The water fills the VLS tubes after they are fired and help, but does not eleminate, the difference in mass. Any addition trim is handled by the trim tanks. When I first got to the boat we were not weapon nor VLS certified. Went out with 4 warshots (cause a us sub does NOT go out without the ability to defend herself) and VLS was empty (they had weighted dummy cylinders in them if I remember correctly). Did not make that much difference to anyone as I remember. Granted, I was a nub then and did not pay attention to much in the forward end of the boat. I remember AFTER we got VLS certified they had to come back and do a trim adjustment on the boat. They came down and took some hard mounted weight OUT of the engineroom. Weapons must not have been as heavy as they thought huh? I am not sure how much they took off but it was enough to worry the dive and OOD that first time out. Only other time I ever saw them adjust the trim of the boat was when we did a battery changeout. That was were I learned some of this. Us nukes, we were always asking stupid questions.

Finally, what if the ship travels from one ocean to another? For example, the ship travels from the Med to the Red Sea. Does the change in salinity affect the CB & CG and therefore the trn radius?

Salinity will affect bouyancy. Yes, it will, but the MASS of the boat and the distribution of said mass will not change. You just have to adjust your trim via the trim tanks to get back to nuetral bouyancy and keep right on steaming.

mmm.. come to think of it. It might change the metacentric height of the boat. The bouyancy will increase(I think the Red Sea is saltier than the Med) but the mass will stay the same. Let me think on this one.

[TopTorp '92]

That's a great explanation Bubblehead! I learned something here.

So, suppose that at the end of the patrol when all or most of the food has been eaten and the TDU weights flushed through the TDU, what would happen to the turn radius? Doesn't all this weight shifting change the relationship between the CB and CG?

Hard de har har. Come on now. When we do that 120 food loadout the trim of the ship hardly changes. We have no room aft, the crews quarters are #10 cans deep, the command passageway is stuffed to the gills, food is EVERYWHERE. A lot of things yes. TONS and TONS?? No. As you eat the consumables and shoot the TDU's you just add more water to the trim tanks to maintain your trim. Compared to the bulk of the sub and the heavy non-movable items, it is really not much to matter. TDU wieghts are not that heavy and we carried OVERKILL amounts of them. Did we ever run out?? Not that I remembered. Also, in my multiple times at cranking I had the pleasure of asking the mess chief (may his red hair never fade) about how we loaded things aft because it made getting to the outboard chiller plants a PAIN and he said they actually loaded food and consumables in the boat in such as way as to eat thier way to the equipment and fairly equally eat fore and aft. Guess there was more to being a cook than making those HORRID rehydrated eggs eatible.

Also, suppose the ship fired its torpedos and cruise missiles. Wouldn't that too change CB & CG?

Refering to the VLS here as well? The water fills the VLS tubes after they are fired and help, but does not eleminate, the difference in mass. Any addition trim is handled by the trim tanks. When I first got to the boat we were not weapon nor VLS certified. Went out with 4 warshots (cause a us sub does NOT go out without the ability to defend herself) and VLS was empty (they had weighted dummy cylinders in them if I remember correctly). Did not make that much difference to anyone as I remember. Granted, I was a nub then and did not pay attention to much in the forward end of the boat. I remember AFTER we got VLS certified they had to come back and do a trim adjustment on the boat. They came down and took some hard mounted weight OUT of the engineroom. Weapons must not have been as heavy as they thought huh? I am not sure how much they took off but it was enough to worry the dive and OOD that first time out. Only other time I ever saw them adjust the trim of the boat was when we did a battery changeout. That was were I learned some of this. Us nukes, we were always asking stupid questions.

Finally, what if the ship travels from one ocean to another? For example, the ship travels from the Med to the Red Sea. Does the change in salinity affect the CB & CG and therefore the trn radius?

Salinity will affect bouyancy. Yes, it will, but the MASS of the boat and the distribution of said mass will not change. You just have to adjust your trim via the trim tanks to get back to nuetral bouyancy and keep right on steaming.

mmm.. come to think of it. It might change the metacentric height of the boat. The bouyancy will increase(I think the Red Sea is saltier than the Med) but the mass will stay the same. Let me think on this one.

Thanks for the submarine enlightenment. I almost forgot what its like to be a "Coner."

[Bubblehead Nuke]

Thanks for the submarine enlightenment. I almost forgot what its like to be a "Coner."

Once a nuke, always a nuke. You know how it is.

I still respect the coner's. After all, someone has to protect that reactor plant and feed the nukes.