Sunday, October 27, 2013

Submarine Questions of the Week - 28 OCT 2013


"why red light is used inside the submarines?"? 

Best Answer (from Yahoo Answers):

I served on Subs during the 70's. On a sub, there is no "night and day" The "day" (at sea)was actually only 18 hrs vs 24 as there were three watches consisting of 6 hours each. You work 12 with 6 off to sleep,study etc. then back to work. Your body clock got very confused, you might get up from sleep only to be served dinner or lunch rather than b'fast. Red lighting in the control room (the only place other than in berthing that the red lights were used.) was only used in preparation of coming to Periscope depth (or the rare surface) or during battle stations when it was dark topside Rig for red served two purposes.First was to acclimate the eyes to darkness of those that were in preparation of going topside during the darkness, and to prevent light from being emitted from the raised periscope. Even though there was a "blackout blind" in the scopes, the crew could not take the risk of light being emitted as it would be able to be seen for miles.  source

More (excerpt):
Red light has minimal effect on night vision because its energy level is so low that the eye doesn't register it strongly enough to produce a compensatory reaction. In near-absolute darkness, both cone and rod cells compensate by pumping out more light-sensitive chemicals. The more time spent in darkness, the more chemicals are produced. In about ten minutes, cone cells max out, producing as much as they are capable of holding.- Hawk

Submarine Questions of the Week

1. Like those giving the above answers, U.S. Submariners probably learned about rods and cones, "the two kinds of receptors in retinas of your eyeballs" during Sub School. But there are several more light receptors in your retina. One of them is essential to maintaining the body's clock. Disruption of the circadian rhythm not only affects body temperature, alertness, appetite, and hormone secretion, etc., research now suggests it may contribute to depression, immunity, and disease.

Unlike rods and cones, which send their signals to the brain's visual cortex, the retinal light receptor governing your body clock sends information to another part of the brain.  What is that special are of the brain called and where is it located?

2.  The "DoD's First Choice for Undersea Biomedical Research" recently announced a collaborative study to phase-shift and/or phase-lock circadian rhythms to optimize operational readiness. Its overall mission to protect the health and enhance the performance of warfighters through submarine, diving and surface biomedical research solutions (see Question 4. below for a simpler statement of goal). What is the official name of "DoD's First Choice for Undersea Biomedical Research"?

3.  Who are the principle collaborators with the military on this new study, and from what institution do they come?

4.  In straightforward terms one of the civilian collaborators was described by an authoritative publication as "working with the U.S. Navy to investigate how light can increase performance and alertness in submariners." Identify the authoritaive, civilian publication.

ANSWERS:  Wednesday, 30 OCT 2013

Submarines are always silent and strange.
working with the U.S. Navy to investigate how light can increase performance and alertness in submariners. - See more at:
working with the U.S. Navy to investigate how light can increase performance and alertness in submariners. - See more at:

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