I am building the Banner 1/350 USS Arizona, and am looking at some reference books with photos. One caption refers to 'range clocks', which seem to have been mounted on the masts of US battleships up untill WWII. They appear to be large silver or white discs. What were they, and how did they work?

By the way, how did the gun directors these ships had prior to WWII function before the use of radar?

One method was the use of optical range finders. Once a range had been calculated, they used an arty technique called “bracketing” until they hit the target. As for the mast mounted disks? no idea.

Ubique

Have a look at the explanation given in the caption to the bottom photograph here - should help

http://www.pastfoundation.org/Arizona/UtahHistory.htm

David,

Thanks for the great reference website
It's all explained there chuckster...
Caption of forth picture

Skipper

I briefly looked at reference, and didn't easily find rangefinding so I'll explain it for those that don't feel like spending a lot of time There is a system called a coincidence range finder. We used to use them on tanks. You have a device that has a mirror on each end (it's those little round things with arms sticking out on your model kits)) and on an individual gun for up close those wings on either side. So you have a mirror on both ends. One is fixed the other moves. You look through the sight and see two of the same images. By turning a crank it changes the angle of the mirror which moves the images together, when they come together that is the range which you find by looking at the dial next to the crank. Now on a tank we were looking at ranges of 2500m or so but our width was about 6 feet apart and maybe 10 feet high. On a battleship the mirrors would be somewhere around 30 feet apart and 100 or so feet high.

On Portuguese Navy Gunnery/Artillery School they had (and as far as I know still do) an old Rangefinder (40's making?) that had the mirrors about 5 meters appart (around 17 ft) and it included three operators - one of them sitting perpendicular to the mirror "tube"!

This kind of range finders were abandoned when the first fire control radars were introduced, leading to the extintion of one class of gunners: Rangefinders - or in portuguese "Telemetristas"

Skipper

HA! I love this site! You learn something new every day......Thanks David for the URL and Thanks Chuckster for asking that question!

The biggest part of the gunnery problem has always been knowing the range to the target. Before radar and laser range finders it was trickey and you had to do some amount of guesswork and estimation. If you have two observers both looking at the same object in the distance, the two of them, plus the target form a triangle and if the two observers are far enough apart, you can use trig and solve for the range pretty easily. The trick is having the "observers far enough apart. The optical range finders Steve mentions with a "base" of about 6 feet can do a pretty good job at ranges in the 2000 to 3000 meters, which is good enough for a direct fire weapon like a tank, especially for use in a European war, which is what everybody expected to fight.

And as Rod says, once you start shooting you use the bracket method until you get a target hit.

Tom

Getting the range is only the first of your worries with naval gunfire...

More problems arise in shooting from a moving platform at a moving target. It's relatively easy to find out your own course and speed, less so for the target, which may of course change both in the time it takes to shoot. By the 30s mechanical computers were used, prior to that there was a lot of trigonometry....

Next time I go to HMS Belfast I'll spend less time playing with the Bofors and some more time in the transmitting station having a look at the gunnery control computer. Then maybe I'll be able to explain (not promising anything )

You're right of course, that naval gunfire is more complicated. I was considering the problem from the static "field artillery" perspective.

Another issue to be dealt with, though perhaps not quit the problem it was during the age of sail, is the roll of the ship. Firing on the up roll increases the elevation and (up to a point) gives a longer range on the shot.

To be as consistent as possible, given the fact that every weapon will still have a "scatter" even when fired at the same data, you'd probably have to shoot at the same point of the roll to increase your accuracy I'd guess.

Tom

If you check out the turrets on any of the US BBs that are now memorials you will find a primitive analog (as in cams and wheels) computer that would calculate the aim point based on ship speed and course and estimated target speed and course. I understand the fire control directors also added met data into their firing solutions. My first tank (an M-48A1) had a small analog ballistic computer that worked the same way.

That was my tank too. Tom were you in tanker platoon as well? Or did you only play with boom-booms?

Sorry guys some of us have some shared experiences. What Chuck is referring to is what we called the ballistic computer, you would index the type of round you were firing (Sabot, HEAT Beehive) by pulling a handle then turning it to the desired round. This would set the cams which would either lower or elevate the main gun slightly to match the type of round (they all had different trajectories) the gunners sight would remain fixed though. We called this super-elevation. This was used on the M60 series tanks as well.

Nah, I wound up in Cadet Battery.

I had wanted to be in the Tanker Platoon and go Armor, just like my dad who was VMI 49-C. But when we did our branch selection at the beginning of 2nd Class year, there were WAY too many guys who picked Armor, and nowhere nearly enough signed up for FA. The guys in the Toolshed HAD to have an approximately even distribution. They said if we didn't voluntarily switch, they'd do it for us based on math test scores (seems there was a minimum cut-off required to be in the FA section.) Since like all good VMI cadets, NOBODY volunteered, they started at the top of the math score list, and the Armor section wound up with all the English/History LA's and all the EE/CE's wound up in the FA section.

The rest is history!!!! The good news was the for 2 years I studied in ROTC class the exact same POI that I wound up having when I got to Ft. Sill (except for the live fire shoots), and so OBC was piece of cake.

Tom

I wonder if they still do that at the "I". Of course, we had the same thing in Armor. Even though the 48a1's were 90mm gas-burners, there were still a lot of similarities with the 60's. PLus we learned armor tactics, some maintenence so we too were ahead of the game , almost on a par with the West Pointers. Being an avid modele rpaid off for me because I knew my vehicle identification. That and my study of soviet tactics got me into TS Spook stuff. Shoulda stayed in, I'ld be driving around Bahgdad in a Humvee right now :-)

Sadly, the answer to you question is no, they don't have Branch Specific Army ROTC any longer.

Even during the days of "mandatory commissioning", I understand that seldom did more than about 70% of any graduating class also receive a commission, due to various physical and other disqualifying factors.

When VMI dropped mandatory commissioning in the '80s (several reasons, most lame IMHO), the ROTC department, no longer assured of a large supply of contract cadets, cut back somewhat and I believe that's when Branch specific sections went away. I don't know if any school still does that, but I can find out. Even though it is still a requirement to take 4 years of ROTC classes, Cadet Command was reluctant I guess to supply instructors for students they wouldn't "gain".

Another sad fact is that since the ratline and the entire system of class privileges and all that goes on in barracks does not conform to Army Regs and DOD policies, (WHAT?!?!?!? You STRAIN new cadets?????)
the members of the ROTC Departement, while they still function as Company Tac Officers, are no longer allowed to perform duties in barracks such as serving as OC, because of the "conflict".

I know GEN Peay is trying to bring back mandatory commissioning, and I applaud him for the effort and hope he suceeds. There has been a LOT of griping by citizens of the Commonwealth of Virginia complaining that Virginia MILITARY Institute, only commissions something like 30% of her graduates.

Hell, even TECH does better as a percentage of cadets enrolled in ROTC, and that's pathetic IMHO.

Maybe if "mandatory commissioning" returns, (and there are some really GOOD reasons VMI should bring that policy back!) they may be able to bring back Branch training with it. A good friend of mine is currently DCG of Cadet Command, so I'll let you know.

Sadly, the tanks and the howitzers (along with White's Farm) are gone, along with family style dining and marching to class.

Not all change is progress.

TC Class of '72

As usual, we've commandeered the thread into a VMI thing, but as no one has ever had a problem with it. If anyone outside the family has a question Tom, or Chuck, or I will be happy to explain.

Tom
I thought they brought back the family syle dining several years ago. Did they cut it again. All those fun days of Hup-2-3-throw. I taught my scout troop that at summer camp, except we alawys sent the "cadet" waiter back for seconds. No...we didn't "dump" :-)

30 % commisioned. This is that female thing. I still can't believe we lost that case. We were right, it did destroy what VMI was. Next to go will be the Ratline as that wil be HAZING. Then they'l wall in the stoops, Air condidtioners and carpet in the rooms
We used to always joke about "back in the old corp" stories, It has become a harsh reality now.

Last time I was in the mess hall, about 5 or so years ago, they were doing cafeteria style. I just can't get my mind around that concept for Club Crozet!!

I thought I heard that at some point after they went to cafeteria style, the briefly went back to family style but returned to cafteria style not long afterwards.

They have been conducting a VERY major renovation of the mess hall, and if it isn't already in place, I know that Gen Peay is very much interested in bring back family style and I'm ALL FOR IT!! Don't know about you and Chuck, but some of the funniest (and most tense) moments I recall took place there. I don't know if you do, but I KNOW Chuck remembers "snorkeling contests" :-) :-)

Actually the decrease in commissioning really isn't related to the admission of women. In fact I think that the female commissioning rate is WAY higher than the male rate. I commissioned a brand new female 2LT just this year who had been an enlisted soldier in my Reserve unit, wanted to get a commission, and asked me where I got mine, because she wanted to go to the same place!! She finished in 4 years despite having been away from the Institute for almost an entire semester when her Guard unit got mobilized.

TC

I never snorkled. I just flat refused Once for gravy the other jello. I remember having to scream "There's always room for jello!" Food fights I remember quite well. Dinner always seemed to be the time and It always started out with those rolls. God, they were perfect for throwing. I also remember having to get up on the cadet waiter stand and dancing for everyone. I did a soft shoe that got compliments.

Glad to hear about the young lady. I'm still "old Corp" enough to oppose what was done and I don't think anything will ever change my mind.

How do they deal with rats and computers. We were restricted from steros , radios etc (as I know you were), but the compters today have all the access to music and games or did that go by the wayside? What about the RDC?

The RDC is alive and well, although they no longer meet in the 5th stoop tower rooms of old barracks like "back in the old Corps". It may be bit more toned down than we remember, but I believe it still operates in much the same way.

As far as computers are concerned, there was a HUGE debate about them over the last several years. Many felt that bringing them in defeated the entire purpose of no "radios" for Rats, and it does. There was also a LOT of discussion about downloading things of the internet (such as napster) as it relates to the Honor Court. Suffice to say the rules are much more strict in barracks than your average 18 year old would be used to, but then what else is new.

I believe that the entire barracks has been wired including the 4th stoop. It was decided that since the real world as well as the academic world really cannot function without computers, and that they truly facilitate the education process, especially research, that it was just dumb for rats not to have them. Sort of like preventing us from having typewriters when we were rats.

If there's anyone ELSE reading this thread, :-) a "typewriter" was a "manual word processor" which linked the keyboard directly to the printer. :-) :-) :-) :-)

TC

:-) :-) Typewriter now that's funny. Carbon paper and in triplicate goes along with that

I am reminded of a joke on one of the comedy shows. A kid was being punished by being placed on room restriction and the other parent commented "Yea sure, he has a TV, DVD, computer and an X-box, how much punishment is that." I guess same thng goes now as those computers can hook into TV , play dvd's and have tons of games on them. A 5-1-5 doesn't hurt so bad now. You still probably get those 2 30 minute sign outs to go to snack bar or a run to what used to be the concourse to get your junk food fix. Well the times they are a changin" Compared to what we wet through the system is like regular college was, nowdays, I guess it is pretty tough in comparison. I get to experience it first hand in my Paralegal studies