Diving and the MBT Gauge

Dredd52 · 05-13-14, 09:40 AM

Hi fellas,

I've been trying to understand how the ballast tanks in an American submarine work, using the NAVPERS 16160 Fleet Type Submarine manual. The impression I've received is that in order to dive, the main ballast tanks (MBTs) and negative tank fill, giving the submarine negative buoyancy - in other words, it displaces less water than it weighs, and sinks. While underwater, the MBTs remain completely filled, and the variable tanks are used to achieve negative, neutral, or positive buoyancy. I've been struggling a little to understand exactly how buoyancy works, but I've read that it does not alter with depth, and that a "dive" setting of the submarine will mean continuous descent, no matter the depth, and a "surface" setting will mean continuous ascent.

Upon executing a dive in SH4, however, instead of immediately filling, the MBT gauges fill up steadily as the submarine sinks, and level off when the submarine does. This suggests to me that a submarine has to take on so-and-so amount of weight to descend to a specific depth, and must take on even more weight to descend further - which contracts my present understanding of buoyancy. I've added a couple images demonstrating this - one at 150 feet, the other at 200.

Am I reading the wrong gauge, and is it something to do with outside water pressure? Or am I misunderstanding how submarines work? I've added RFB and the RSRD campaign mod, if that makes a difference.

05-13-14, 09:40 AM	#1
Dredd52 Nub Join Date: May 2014 Posts: 3 Downloads: 32 Uploads: 0	Diving and the MBT Gauge Hi fellas, I've been trying to understand how the ballast tanks in an American submarine work, using the NAVPERS 16160 Fleet Type Submarine manual. The impression I've received is that in order to dive, the main ballast tanks (MBTs) and negative tank fill, giving the submarine negative buoyancy - in other words, it displaces less water than it weighs, and sinks. While underwater, the MBTs remain completely filled, and the variable tanks are used to achieve negative, neutral, or positive buoyancy. I've been struggling a little to understand exactly how buoyancy works, but I've read that it does not alter with depth, and that a "dive" setting of the submarine will mean continuous descent, no matter the depth, and a "surface" setting will mean continuous ascent. Upon executing a dive in SH4, however, instead of immediately filling, the MBT gauges fill up steadily as the submarine sinks, and level off when the submarine does. This suggests to me that a submarine has to take on so-and-so amount of weight to descend to a specific depth, and must take on even more weight to descend further - which contracts my present understanding of buoyancy. I've added a couple images demonstrating this - one at 150 feet, the other at 200. Am I reading the wrong gauge, and is it something to do with outside water pressure? Or am I misunderstanding how submarines work? I've added RFB and the RSRD campaign mod, if that makes a difference.