Friends,

 

As some of you know, I do a bit of writing for Steve Jackson Games. The new version of GURPS has a wonderfully streamlined system for vehicles, very useful for GURPS itself, but some of the statistics are a little hard to track down for those of us trying to write game versions of various real world vehicles.

 

I was wondering if anyone knew of any good sources for the following information...

 

For ships and submarines:

 

1) Although it is not too hard to find the standard displacements and full load displacements for warships, for a lot of cargo ships, they only list tonnage (which is a measure of volume, not actual mass). While I am sure using tonnage and gross tonnage and so on is very useful to the people who actually use these ships to earn a living, I'm afraid the statistic is useless to me. Are there any guidelines or formulas for estimating displacement based on tonnage? (Or simply any reference works that just list the standard and full displacements for these ships? This would be easier and therefore preferable.)

 

2) How fast do big ships accelerate? Top speeds and cruising speeds are very easy to find; they're listed in most reference works, etc. But how long does it take a boat or ship to reach this speed from a dead stop? I've heard the LCS can get to 45 knots in about two minutes and a Spruance can get to 33 knots in about twelve minutes. I've also heard that a large cargo ship can usually get from a dead stop to 15 knots in about 15 to 30 minutes. For smaller boats, cabin cruisers and the like, this information is sometimes available (many boat reviews include a 0-20 knots or 0-30 knots time), but I haven't found much for larger vessels. Are there any guidelines, reference works, observations from the personal experiences of fellow forum members, etc.? What about submarines?

 

3) If there are any important differences for #2 (i.e., the acceleration issue) between conventional and nuclear systems, gas turbines compared to older kinds of steam vessels, etc., could someone explain the basics?

 

Thanks in advance.

 

Mark

Not directly relationated or not hard data, but the articles about "Speed Thrill" and "Speed" in

http://www.navweaps.com/index_tech/index_tech.htm

are worth of mention, and I think you can get some hints on it, specially in relation to nuclear propulsion.

Friends,

 

As some of you know, I do a bit of writing for Steve Jackson Games. The new version of GURPS has a wonderfully streamlined system for vehicles, very useful for GURPS itself, but some of the statistics are a little hard to track down for those of us trying to write game versions of various real world vehicles.

 

I was wondering if anyone knew of any good sources for the following information...

 

For ships and submarines:

 

1) Although it is not too hard to..............idelines or formulas for estimating displacement based on tonnage? (Or simply any reference works that just list the standard and full displacements for these ships? This would be easier and therefore preferable.)

 

2) How fast do big ships accelerate? Top speeds and cruising speeds are very easy to find; they're listed in most reference works, etc. But how long does it take a boat or ship to reach this speed from a dead stop? I've heard the LCS can get to 45 knots in about two minutes and a Spr.................ny boat reviews include a 0-20 knots or 0-30 knots time), but I haven't found much for larger vessels. Are there any guidelines, reference works, observations from the personal experiences of fellow forum members, etc.? What about submarines?

 

3) If there are any important differences for #2 (i.e., the acceleration issue) between conventional and nuclear systems, gas turbines compared to older kinds of steam vessels, etc., could someone explain the basics?

 

Thanks in advance.

 

Mark

Can't help with specific data but in regards super heated steam turbine systems (common from I think WW2 till early 80's) they are very slow if caught off guard but relatively quick if the boiler room is given notice-

The steam system must be kept superheated or the turbines will be pretty much be written off. That means the total energy in the steam system (inticated by pressure and temperature, critically at the exhaust of the last section of turbines) must be kept above a critical level. The energy in the steam system is a bit like momentum in a truck, slow to put in but if built up it can do a lot of work. .. So eg if steaming slowly up harbour towards coming alongside a warf (especially if no tugs) the engines are pretty well just ticking over and taking little energy out of the steam system BUT nearing the warf the boiler will be stocked up so as to put extra energy into the steam system and when the manourvering starts to come along side (an inexperienced officer at the con can use a lot of steam in this manourver) the energy is there for instant use. Same thing if eg you're about to do an alonside unrep where you've been ticking alone then go into full acceleration then come back to a cruise.

If caught with pants down, the energy has to get put into the system before you can even tweek the trottle, let alone go flank. I can't remember times but certainly minutes before you really get anything happenning.

Ofcourse if there is a known risk you're not going to cruise along without some buffer, ie you'll be running the steam system with a higher energy level than needed (without going over the max limits) and then if needed you can open the taps on the turbines pretty full at the same time as the boiler room punching in all your big oil nozzles to pump as much heat into the system as you can.. and the accelleration is pretty good.

Don