[TopTorp '92]

Originally Posted by Dr.Sid

I'm tuning my first simple movement model for my subsim. I'm trying to set it to some realistic behavior. There is however too many things I don't know. So I have few questions.

I found on internet some data about subs, for example good old 688. I have weight, size, engine power, maximum speed. Now this alone is almost enough for much of the simulation. But not all, and I also need as much real data as possible to see if my model indeed is realistic. I'd like to know:

1) Acceleration at different speeds, especially at 0. (Too technical for recent memory)
2) How long the subs takes to stop after engines are cut off. (No recollection)
3) Does sub have screw with variable pitch ? How is it used exactly ? (Screw isn't variable)
4) What is the turning rate at different speeds ? How much rudder is needed to achieve this ? (ruder angle combined with speed determines turn rate. Generaly, we were looking for about 3-5 degrees per second. If you turn too fast you risk rolling the ship over.)
5) Why do subs have lower max speed on the surface ? (Lower surface speed because of its shape. It looks like a pipe or a cigar.)
6) How is the depth controlled ? How much does the tanks, how much the planes ? How strong effect trim tanks has ? How are they used ? How are the common surface and dive procedures from these aspects ? (See link below. That book does a really good job at describing most of the control features of submarines. In brief, the trim system controls ship's weight with reference to achieving one of three states: Light overall (LOA), heavy overall (HOA), or OK overall (OKOA.) When I was a chief of the watch we always trimmed the ship LOA and used control surfaces to maintain depth. However, if you decide to start shooting several torpedoes, then you will trim the ship HOA expecting the ship to lighten up after you finish shooting torpedoes.

Please don't wild guess. I can do that too. I want some real info, with references, if possible.

See link below. This book does a nice job of explaining much of the complexity associated with trim systems and control surfaces.

Complete Idiots Guide to Submarines: http://www.amazon.com/Complete-Idiot...6082917&sr=8-1