SUBSIM Radio Room Forums - View Single Post - Speed number--figuring out ships speed

BigWalleye · 05-14-17, 10:14 PM

Some observations:

1. We are at an advantage over our RL counterparts. We know that AI ships only move at speeds in integer knots. Check in the campaign.xxx files. Or turn on the God's eye view so you can get exact data. You'll see what I mean.

2. Knowing the target's speed to better than the nearest integer is not necessary for a successful firing solution. The target is BIG. At 1000 meters, optimum firing range as recommended by KM doctrine, a 140 meter long ship will subtend 8 degrees. The lead angle for a 90 degree shot is 14.5 degrees for a target moving at 10 knots. So if you aim for the center of the target, you can have a speed error of 27% at 1000 meters and still hit. At 2000 meters, quite a long shot, the allowable error drops to 14%. That's 8.5 kts, instead of 10kts. It is not difficult to distinguish between 8.5 and 10 kts.

3. Submarine commanders were warriors, not engineers and certainly not accountants. If you read the first-person accounts, they didn't attempt to determine target parameters with great accuracy, just enough to get the torpedo on the target with a good probability of success. Better to fire two fish, hit, and retire than to try for the perfect shot, get detected, and have to abort the attack. I don't recall ever having read of an RL sub skipper who regarded the attack as a math problem. That's for staff officers.

Remember that the torpedo is a big, powerful weapon. Any hit will do a lot of damage. A heart shot is not needed.

05-14-17, 10:14 PM	#8
BigWalleye Sea Lord Join Date: Jul 2012 Location: On the Eye-lond, mon! Posts: 1,987 Downloads: 465 Uploads: 0	Some observations: 1. We are at an advantage over our RL counterparts. We know that AI ships only move at speeds in integer knots. Check in the campaign.xxx files. Or turn on the God's eye view so you can get exact data. You'll see what I mean. 2. Knowing the target's speed to better than the nearest integer is not necessary for a successful firing solution. The target is BIG. At 1000 meters, optimum firing range as recommended by KM doctrine, a 140 meter long ship will subtend 8 degrees. The lead angle for a 90 degree shot is 14.5 degrees for a target moving at 10 knots. So if you aim for the center of the target, you can have a speed error of 27% at 1000 meters and still hit. At 2000 meters, quite a long shot, the allowable error drops to 14%. That's 8.5 kts, instead of 10kts. It is not difficult to distinguish between 8.5 and 10 kts. 3. Submarine commanders were warriors, not engineers and certainly not accountants. If you read the first-person accounts, they didn't attempt to determine target parameters with great accuracy, just enough to get the torpedo on the target with a good probability of success. Better to fire two fish, hit, and retire than to try for the perfect shot, get detected, and have to abort the attack. I don't recall ever having read of an RL sub skipper who regarded the attack as a math problem. That's for staff officers. Remember that the torpedo is a big, powerful weapon. Any hit will do a lot of damage. A heart shot is not needed.