Civil War Torpedo Incident Trivia Question

CSS Saint Patrick attacks the USS Octorara



The former was a Confederate torpedo boat and the latter a blockading Union Steamer patrolling Mobile Bay. See http://diversitytomorrow.com/member/odiousgambit/blog/#post23 for more background if interested.

I was utterly unable to even begin to solve the math problem in the thread https://wizardofvegas.com/forum/questions-and-answers/math/15727-surface-to-air-missile-problem/

However I hold some interest in the topic and a trivia question came to mind. It's not mathematically oriented except possibly in concept; I consider it hard.

Trivia Question: The Octorara was underway, thus the CS attack involved the complicated circumstance of a moving attacker attempting to intersect with a moving target [as we saw in the other thread].

Assumptions:

Assume the Saint Patrick did not merely follow the Octorara in order to intersect with it, but instead ...

Assume, additionally, the Reb boat needed to plot the most efficient course from a different bearing than directly or generally to the target's rear.

The Question: What sailor's technique for efficient interception was most likely used?

I think the heat seeking missile problem parameters where the missile is only 10% faster than the plane, is actually more appropriate for two ships where one is slightly faster. Instead of altitude the two ships are 5 km apart east and west.

1) 65.465 seconds - faster possible intercept time match horizontal speed and use 10% advantage to edge closer
2) 157.14 seconds - always pointing at the target
3) 300.00 seconds - close horizontal separation of 5 km in (5 km / 11 km/s) seconds and then conduct tail chase.

All of these scenarios are wasteful or dangerous in reality.
1) The fastest possible time would be easily confused by a target varying speed. You may find yourself in front of your target, and go from hunter to hunted.
2) Always pointing at the target would involve too many course corrections, and waste too much time
3) Closing the horizontal distance first in 27.3 seconds would be the safest thing, but you would give up too much time as your target pulls away

Consider the compromise
86.039 seconds - tactical compromise where the pursuer aims 8 km ahead in the direction of the targets direction, and then engages in tail chase
51.458 seconds + to close horizontal separation and advance 8 km
34.581 seconds for tail chase

You can see that the final scenario is much closer to a real tactic. The real tactic involves two fundamentals
(1) You are anticipating his direction,
(2) but you are careful to leave some tail chase where you have the advantage.

Of course, there are rare cases where the pursuer does not have a speed advantage. These tactics are much harder and clearly much more dangerous. You have to avoid wide angles of tail chase, and make much bolder moves anticipating his direction and course changes.

Quote: pacomartin

the heat seeking missile problem parameters where the missile is only 10% faster than the plane

This has to be the very definition of a "SAM" missile that is fairly ineffective, i.e. only slightly faster than its target. No?

The tactic of "leading", not following, the target has to be employed, I think, anytime speeds are remotely comparable and I don't doubt the Confederate torpedo boat had to do this. Which means that to "lead it", though correct, is not the answer to the trivia question I am looking for. [g]

Quote: pacomartin

there are rare cases where the pursuer does not have a speed advantage. These tactics are much harder and clearly much more dangerous. You have to avoid wide angles of tail chase, and make much bolder moves anticipating his direction and course changes.

This may have been the case with the Rebs at question, who knows? If I understand that problem correctly, then there is no choice but to approach the target at some angle less than 90 degrees if the 2 courses, target and pursuer, are equidistant. Or get closer so that the course of the pursuer is shorter than that of the target to their attempted intersection.

Quote:

The fastest possible time would be easily confused by a target varying speed

Correct me if I am wrong, but I believe early torpedo warfare had to assume the target would maintain constant speed and heading.

Quote:

The Question: What sailor's technique for efficient interception was most likely used?

I'll have to start dropping hints.

No boating enthusiasts out there?

The situation differs from later torpedo warfare in that submarines etc. basically needed to calculate what they called "the solution" for a course for their launched device traveling a certain heading and speed to intersect with the target which had to be assumed to be maintaining a constant heading and speed. This is why zig-zagging was effective against submarines. This calculation was difficult, but necessary. The early torpedo was designed to be given a certain heading and speed which it would maintain in order to intersect with the target.

But the Civil War torpedo boat with an explosive device attached to a boom at the bow thus did not launch any independently traveling device; a good sailor would then know how to best intersect with the target without calculating a heading.

It is helpful to know the difference between "heading" and "bearing". A heading is the compass direction an object is traveling. A bearing is the compass direction other objects on the horizon are observed as maintaining. Per wikipedia: "It typically refers to the direction of, some object, as seen by us, compared to our current heading."

Quote:

The Question: What sailor's technique for efficient interception was most likely used?

well, here's the next hint:


Boaters make an effort to avoid collisions with other boats.

If, however, a collision, or let's say an interception, was desirable, they would then just reverse procedure.

Using the correct technique would take the torpedo boat to the target in the most efficient course. In this case, the torpedo boat was also the torpedo! If they had to make course corrections, losing efficiency, the target may have started to get away from them. After all, something went wrong.

For the trivia question, the assumption is that the technique for the most efficient course *should* have been in their knowledge base if they were true sailors or had consulted such.

So far this has not been google-able except to someone who would know already. I've been checking that.

Quote:

The Question: What sailor's technique for efficient interception was most likely used?

Next hint, "Rule 7"

Google will have it if the right combination of words is used. You may have to know what you are looking at, though.

I read rule 7 and don't see how it applies. Rule 8 might, though.

I would guess that the attacker would first sail parallel to the defender, then turn toward, maintaining speed/accelerating so as to not fall behind.

Quote: Mosca

I read rule 7 and don't see how it applies. Rule 8 might, though.

Assuming we are looking at the same thing, this previous hint applies:

Quote: odiousgambit

Boaters make an effort to avoid collisions with other boats.

If, however, a collision, or let's say an interception, was desirable, they would then just reverse procedure.

Many boaters never give much thought to collision, they are on constant lookout. The problem really arises when vessels want to keep the same heading and "get somewhere" but at the same time observing other vessels may get sloppy.

Quote: Mosca

I would guess that the attacker would first sail parallel to the defender, then turn toward, maintaining speed/accelerating so as to not fall behind.

This would not be the shortest course, something that could be critical. So the answer assumes it was critical to get right.

Maintain the exact same relative bearing. Target should get bigger.

Quote: odiousgambit

Next hint, "Rule 7"

Google will have it if the right combination of words is used. You may have to know what you are looking at, though.

I had to cheat to find out. Thank you.

Quote: thecesspit

I had to cheat to find out. Thank you.

About time it was revealed anyway.

http://navruleshandbook.com/Rule7.html

Quote: link

The classic test of risk of collision is given special attention in the final paragraph of Rule 7: if your vessel is holding course and speed, and you take several compass bearings on another vessel and those bearings are all about the same, then you will collide with the other vessel if it is also holding course and speed and if one does not take evasive action...

In other words, if something on the horizon is staying at the same bearing, constantly getting closer, then you are on a collision course.

So, you are correct, the corollary if *seeking* collision is to purposefully maintain the target at a constant bearing where it will naturally "settle", so to speak, as you tweak your own heading.

It's a remarkable thing to me, really, to realize that launching a torpedo during the world wars meant mind-stumping mathematical calculation ... and that it was top secret in WW2 that the US had a machine to calculate such ... yet, if the torpedo itself had an operator that could see the target and adjust, a silly thought, all that calculation was unnecessary.