WET THRUST CONVERSION - pounds vs inches

2 posts ยท Nov 30 1997 to Dec 1 1997

From: Bruce S. R. Lee <bsrlee@w...>

Date: Sun, 30 Nov 1997 21:10:56 +1100

Subject: Re: WET THRUST CONVERSION - pounds vs inches

(hack)
> Yes it is the actual conversion rules I want and what makes things
(chop)

The most common sizes that I know for WW2 (all services): 1 lb = 37mm
2lb = 37/40mm
3lb = 47 - 50mm/ 2 inch
6lb = 57mm
12lb = 75mm/3 inch
18lb = 75mm/ 3 inch
17 lb = 76.2mm / true 3 inch
20 lb = 84 mm
25lb = 88mm / 3.45 inch

As you will see there is some overlap which reflects the two systems of
measuring calibre in pounds - the smaller size is usually the weight of
a sherical solid cast iron shot, the heavier numbers are for the actual
explosive filled 'conical' projectile - hence may variations around 75
mm -
there was a 13lb.er in WW 1 which was also 3 in.

hope this may help a bit, I do have some conversions for larger solid shot if
I dig around, but these don't really apply after 1900.

From: B Lin <lin@r...>

Date: Mon, 1 Dec 1997 15:13:17 -0700 (MST)

Subject: Re: WET THRUST CONVERSION - pounds vs inches

> On Sun, 30 Nov 1997, Bruce S. R. Lee wrote:

> (hack)

The conversion numbers are then

15-20mm         every 20 or fraction greater than 10 makes 1 PDAF
21-40mm         Every 20 or fraction greater than 10 makes 1 ADAF
41mm - 6 inch   every 3 or 2 = 1 C batt (surface, AA or Dual)
7 inch 1 = 1 Cbatt 8 inch 2 = 1 B batt 9 inch 3 = 2 B batt 10 inch 1 = 1 B
batt 11 inch 2 = 3 B batt 12 1 = 2 B batt
13/14           3 = 2 A batt
15 4 = 3 A batt 16 1 = 1 A batt 17 2 = 3 A batt 18 1 = 2 A batt

Torpedoes are rated by number of tubes in the launcher i.e. 4 tubes = quad
launcher, with a number of reloads if known.

The above are slightly modified to try to get some designs to make more
statistical sense. For instance if a ship has a middle turret with only 2 9
inch guns I will give it the beneift of rounding up and give it 2 B
batts P/S.  German 15's are actually more powerful than the equivalent
British and so the 15's on the German ships are rated at 4/3.  British
ships may be closer to 3/2.  Fiddle with the values until you get
something that sounds reasonable. One deal is with the fire arcs. In actuality
only centerline turrets have true F or A arcs, the others really only have
half a F or A arc. i compensate by limiting most
non-centerline
guns to 2 arcs.

--Binhan