Technology and Operations
This forum is for discussing technological & operational matters pertaining to U-boats.
Re: Hydrophone operation.
Posted by:
JTMcDaniel
()
Date: March 19, 2009 10:09PM
Actual visibility at sea on a clear day (in miles) is 1.2246 x the square root of the observer's eye height above the sea (in feet). U-boats being fairly low in the water, say the lookout's eye level is about 10' above the surface gives a horizon of just under 4 miles. Of course, the target sticks up above the horizon, so if the highest visible part of the target in 40' above the surface, it can been seen (by that lookout) at a distance of about 11.6 miles (3.87 mi lookout's horizon + 7.74 mi, target's horizon).
Of course, what was most commonly the first thing spotted was smoke, which might be visible at 20 miles or more, presuming a skilled lookout (who could tell the difference between distant smoke and a dark cloud), and a few ships in the convoy with old coal-fired boilers to insure lots of black smoke).
Radar horizon is the same as the visual horizon from the same height, again plus the target's horizon distance, though radar is a bit more likely to notice something than a lookout. In the U-boat war, radar was mostly an enemy advantage in any case, most U-boats not having it, and the few that did probably (rightly) suspecting that the enemy could detect their signal a lot farther out than their radar could detect the enemy.
J.T. McDaniel
Of course, what was most commonly the first thing spotted was smoke, which might be visible at 20 miles or more, presuming a skilled lookout (who could tell the difference between distant smoke and a dark cloud), and a few ships in the convoy with old coal-fired boilers to insure lots of black smoke).
Radar horizon is the same as the visual horizon from the same height, again plus the target's horizon distance, though radar is a bit more likely to notice something than a lookout. In the U-boat war, radar was mostly an enemy advantage in any case, most U-boats not having it, and the few that did probably (rightly) suspecting that the enemy could detect their signal a lot farther out than their radar could detect the enemy.
J.T. McDaniel
Subject | Written By | Posted |
---|---|---|
Hydrophone operation. | Oxullop | 01/25/2009 06:29AM |
Re: Hydrophone operation. | ROBERT M. | 01/25/2009 09:06AM |
Re: Hydrophone operation. | Oxullop | 01/25/2009 09:12PM |
Re: Hydrophone operation. | Oxullop | 01/25/2009 09:27PM |
Re: Hydrophone operation. | ROBERT M. | 01/25/2009 09:58PM |
Re: Hydrophone operation. | Oxullop | 01/26/2009 02:39AM |
Re: Hydrophone operation. | behblc | 02/04/2009 03:00PM |
Re: Hydrophone operation. | Don Prince | 03/15/2009 03:22AM |
Re: Hydrophone operation. | JTMcDaniel | 03/19/2009 10:09PM |