Being from the Mine Warfare world I can tell you that differential steering is a way of life for smaller ships to aid in maneuvering. Part of that is the fact that we had Controllable Pitch Propellers (CPP's) and could reverse thrust without reversing the rotation of the shafts. Larger ships do use differential steering, HOWEVER it is used almost exclusively in port for tight quarters maneuvering with the aid of tugs. To reverse thrust on a shaft on a large vessel without CPP's (meaning reverse rotation). You typically must: -Reduce all power to shafts, lower ships speed -Kill the ahead bell on that shaft -Allow the shaft to slow down to an "idle" speed, also known as "freewheeling" -Apply the brake to that shaft to stop all revolutions -Engage the shaft locking mechanism -Engage the reversing gear attached to the MRG (Main Reduction Gear) -Disengage the locking mechanism -Release the braking mechanism -Bring shaft RPMs back up Again, this is to the best of my knowledge. However seeing as I have been underway on minesweepers (american and british), submarines, and large surface vessels (DDG and a supply ship) I imagine it is reasonably accurate. This is virtually the same procedure on all those vessels. A much more realistic representation in the hobby is to allow power to be cut to a shaft but no reverse thrust applied. Being as ships couold cut power to any shaft then you should be able to as well, and in whatever manner benefits turning the best. Das Butts
Having been a Gas Turbine Engineer for five years on a Spruance class destroyer, I can concur with what Mike says. We had CRP props which could stop the ship in one length from full ahead. Shook the hell out of the boat when doing that though. Regarding the time it took for these old steam ships to stop and spin a prop in reverse is true, but it is as true in differential maneuvering at slow speed as stopping and reversing in a straight line from full speed ahead (a common practice in model warship combat if I recall ;-).
Absolutely a very valid point. So the reasonable choice seems to be if a combat reverse is allowed then differential steering should be allowed as well. But the power in either direction of rotation will not exceed the amount needed to "make speed". All as Mr Tyng suggested 3 posts before: ) This is where the Big Gun fellas balk and I wish they would reconsider. Setup like they are those ships turn like pigs. Albeit, it is more "scale". The fast gun guys do say yes to the reverse and no to differential steering. However with their setups their is much optimization of prop and rudder placement and size that is not allowed in Big Gun/ Battlestations. Does this make differential steering more permissable/ favorable in this fomat? Das Butts
As i recall, the reason we left the original rules that way (Joe's ruleset) was to allow differential steering. We thought it would be very important for subs and other small boats to have the differential steering. If someone were to get subs working in this game, they would need all the manuevering they could get to line up their bows (or sterns) for torpedo shoots... Carl
Somewhat OT but could not the American BB's with turbo-electric drive also switch from forward to reverse rather quickly? I seem to remember reading that some where.
Nope, all that momentum in the driveline being quickly reversed would produce a current spike likely to fry things. Honestly, at battle speeds, I don't see the WW2 and older battlewagons reversing one side and speeding up the other. Unlinking the throttles and operating one set of engines locally (the main control stations don't typically have the means to control each side of the steam plant individually) was a non-trivial thing and one that would not likely be done in combat. If it came to a vote, I would vote no on combat reverse and differential steering because neither would have been realistically used in our time period. SMS Seydlitz steaming home from Jutland in reverse wasn't a combat reverse Another issue with differential steering is that if you hook up an ESC to each drive motor, you could freely have one side all ahead flank and the other all back full, which as Herr Butts pointed out is unlikely to happen in a big steam plant.
I think we should atleast have reverse in our boats. Not everything can or should be totally realistic. I mean, can you imagine if we had to keep atleast 50 meters between our boats while taking shots? I've run boats that have had one direction fail on the throttle, and it really sucks. As for differential steering, I'm not sure it would really be necessary, but maybe depending on pond size, and the length of the hull.
Although we strive for scale, we also have to account for playability. There are situations and battling limitations with models that real ships would never see. Sometimes, the sake of scale has to bow to practicability and playability. I would be in favor of a limited reverse and turning differential. The really big ships may need the better turning in much smaller than scale battling areas.
I'm not sure, but I was told that if full reverse power was applied whils the ship was still travelling forwards, it would cause severe damage to the shaft thrust blocks.
I don't mean that we shouldn't have reverse! I said 'no battle reverse', i.e. I don't think we should have Bismarck backing towards an Iowa that's backing towards him to enter combat. [I am not suggesting such a change to established rulesets, I like Fast Gun as-is] Not having any reverse would be impractical and make bringing the ships in at the end of a battle difficult to say the least. I don't even advocate limiting reverse power, as I'd like to have full power available astern if I wind up about to cross some cruiser's T with Bismarck. I'm sure the cruiser's captain would like me to have full reverse at that time, too. I just don't think that we need to use full reverse to start moving backwards into combat I can flex on the 'no turning motors' thing. I'm not generally in favor of it, but it sounds like a majority are. So if that's the case, my ships will be built to use differential thrust. No biggie.
I think with rotating cannons there will be less of a need to reverse into peoples ships to unload on them. I still think we should be able to. However one thing I do not like to see is propwashing which I think is highly unsportsmanlike to begin with (which is why my local fastgun club doesn't allow it).
My personal experience is that Indiana/ big gun cannons are not terribly effective at longer shots. The "go to" shot is the close broadside. Sometimes off angle in approach up to 45deg or so. Shots over 4' are usually just for fun Das Bütts
One thing I have always asked about "combat reverse" is what is combat reverse, and what isn't? Who is the judge of that, and how is it determined? The answers I have received are all subjective and variable, if defined at all. Without an objective definition, any rule about combat reverse cannot be fairly enforced. Furthermore, the Big Gun clubs that allow it have no problems with ships backing up into combat. Our ships don't handle well in reverse, so there is very rarely a tactical incentive to back up towards an opponent, except when approaching a shore battery.
As I mentioned earlier, the diff steering was envisioned mainly for subs. The diesel-electric subs in WWII used diff steering when needed, and though it caused major cavitation it did not cause damage. This is because the diesel motors ran the generators and electric motors ran the props. Electric motors can be plowed into full reverse very quickly whereas steam and diesel engines can not. Carl
The AusBG dosen't allow combat reverse. It's pretty simple as to what combat reverse is: it's when a ship travels astern in order to gain an advantage. For instance, if you overshoot that transport, you can't back up to get a shot on him.
Not that I have experience with submarine electric propulsion motors but rapid reversals are NOT done routinely. The current surge is enormous and you have to be careful with it. Not arguing against diff steering with this, but had to open my mouth
I dont think any WWII ship stopped on a Dime, would ships have halted a shaft during maneuvers? to help in turning? not necessarily reverse it. I think that I agree with Tug when we should have full power in reverse to avoid crashing into things, but I dont like the idea of any ship fighting while in reverse. The New Jersey or the H at flank speed, and no 100% reverse= tin can being turned into tin-cans..
Just a thought on scoring: my local club is going to try sink points at standard displacement for the lead ship in class as listed in Conway's for our September battle. We are also only going to count the below waterline holes for point as well. We will keep everyone informed on how that method works out.
