WesWorld

I'm posting this as a separate thread since it's not the usual "here's another ship" post like the stuff I did earlier this week. Sorting out the details of the ship is tricky, as I've never seen a hospital ship springstyled in detail, and on-line resources don't really talk much about how much stuff weighs. I've therefore had to make some assumptions with this design and would appreciate some feedback on them if possible.

Dayaa is another late addition to the Indian Fleet Train, a ten year old passenger liner hastily requisitioned as the situation in Asir began to deteriorate, and converted into service in the first half of 1932. Her function is primarily to treat casualties and provide ongoing care to the most seriously injured and/or unstable cases. Evacuation of less seriously injured and/or more stable casualties will be left to other called-up civilian vessels that can perform the function with considerably less alteration.

As the ship is a converted passenger vessel, she retains a high freeboard, thus her stability is on the low side. However, this is one of those rare times where I really want a strong seakeeping rating which, coupled with the good steadiness rating, should help both the staff and the patients greatly. I've read about surgeries in destroyers in the Arctic, in which the ship's doctor can only work because two other guys are holding him in place. I don't want that here.

Current US hospital ships have about a 1:1 staff/patient bed ratio - there's probably some economy of scale, since they're almost as big as aircraft carriers. Still, since medical technology in 1932 is far less advanced, I'm going with a 1.75:1 staff/bed ratio. That's 350 staff, ranging from doctors down to janitors, and 200 beds. I've set aside 3.5 t per person, using springstyle's "steerage passenger" guidelines - the ad-hoc, cramped conditions that suffice for a troopship won't work as well for hospital beds, gurneys, and the wide spaces needed to move casualties around. The staff - who will be working long and exhausting shifts - also need more extensive living space or they'll quickly burn out..

As for work facilities, the 212th MASH website notes that it has 200 t of stuff, including 2 operating tables, a 36 bed ICU, an emergency room, X-ray/lab/pharmacy facilities, and maintenance, power generation, and communications, and cooking facilities - all of it mobile. The ship itself provides for these latter categories, so allowing for the increased bulk of stuff in the 30s, I'll assume that 200 t in 1932 will still get me the same medical facilities as a MASH. That figure is doubled for this ship, and I've added some undefined storage capacity - maybe additional supplies to be sent ashore for disaster relief, casualty stablization and transport.

I've also provided 200 t for two LCIs, davits, and any equipment necessary to take casualties on board.

Finally, I've simmed out the ship with a single machine gun so springstyle won't crash. The ship should be considered unarmed, though events of the Asir conflict could well change that later.

So what I present is a ship designed to provide the same care as two US Mobile Army Surgical Hospitals:

Dayaa, laid down 1922

Length, 131.8 m x Beam, 20.5 m x Depth, 4.6 m
6892 tonnes normal displacement (6134 tonnes standard)

Main battery: 1 x 0.7-cm

Weight of broadside: 0 kg

Hull unarmored

Maximum speed for 4995 shaft kw = 16.75 knots
Approximate cruising radius, 11000 nm / 12 knots

Typical complement: 378-492

Miscellaneous Weight:
-Medical Staff Quarters: 350 @ 3.5 t = 1,225 t
-Patient "Beds" (~10 recovery, 30 ICU, 50 serious care, 110 light care): 200 @ 3.5 t = 700 t
-Facilities (~4 operating tables, large emergency/trauma centre, labs, pharmacy, etc): 400 t
-Supplies: 75 t
-2 x LCI, davits, casualty receiving facilities: 200 t


Estimated cost, $2.636 million (£659,000)

Remarks:

Ship has slow, easy roll; a good, steady gun platform.

Excellent seaboat; comfortable and able to fight her guns
in the heaviest weather.

Magazines and engineering spaces are roomy, with superior
watertight subdivision.

Ship is roomy, with superior accommodation and working space.


Distribution of weights:
Percent
normal
displacement:

Machinery ........................ 227 tonnes = 3 pct
Hull and fittings; equipment ..... 3169 tonnes = 46 pct
Fuel, ammunition, stores ......... 896 tonnes = 13 pct
Miscellaneous weights ............ 2600 tonnes = 38 pct
-----
6892 tonnes = 100 pct

Estimated metacentric height, 0.9 m

Displacement summary:

Light ship: 5996 tonnes
Standard displacement: 6134 tonnes
Normal service: 6892 tonnes
Full load: 7471 tonnes

Loading submergence 1825 tonnes/metre

+++++++++++++++++++++++++


Estimated overall survivability and seakeeping ability:

Relative margin of stability: 1.04

Shellfire needed to sink: 10252 kg = 2155173.5 x 0.7-cm shells
(Approximates weight of penetrating
shell hits needed to sink ship,
not counting critical hits)

Torpedoes needed to sink: 3.5
(Approximates number of 'typical'
torpedo hits needed to sink ship)

Relative steadiness as gun platform, 70 percent
(50 percent is 'average')

Relative rocking effect from firing to beam, 0.00

Relative quality as a seaboat: 2.00

+++++++++++++++++++++++++


Hull form characteristics:

Block coefficient: 0.55
Sharpness coefficient: 0.40
Hull speed coefficient 'M' = 6.95
'Natural speed' for length = 20.8 knots
Power going to wave formation
at top speed: 36 percent


Estimated hull characteristics and strength:

Relative underwater volume absorbed by
magazines and engineering spaces: 53 percent

Relative accommodation and working space: 290 percent


Displacement factor: 226 percent
(Displacement relative to loading factors)


Relative cross-sectional hull strength: 1.07
(Structure weight per square
metre of hull surface: 483 kg)

Relative longitudinal hull strength: 4.16
(for 9.00 m average freeboard;
freeboard adjustment +4.71 m)

Relative composite hull strength: 1.22

+++++++++++++++++++++++++


[Machine-readable parameters: Spring Style v. 1.2.1]

432.30 x 67.24 x 15.09; 29.52 -- Dimensions
0.55 -- Block coefficient
1922 -- Year laid down
16.75 / 11000 / 12.00; Oil-fired turbine or equivalent -- Speed / radius / cruise
2600 tons -- Miscellaneous weights
++++++++++
1 x 0.28; 0 -- Main battery; turrets
Central positioning of guns
:
0 -- No secondary battery
0 -- No tertiary (QF/AA) battery
0 -- No fourth (light) battery
0 -- No torpedo armament
++++++++++
0.00 -- No belt armor
0.00 / 0.00 -- Deck / CT
0.00 -- No battery armor


(Note: For portability, values are stored in Anglo-American units)


+++++++++++++++++++++++++++++++++++++++++++++++++++++++

Doesn´t look too bad to me. However, I´ve nothing about hospital ships in my sources. :o/

You probably need more misc weight because of the huge stores of medication necessary...?!

Gröner has something about hospital ships in volume 5 of his books. Sadly there is nothing about how much space or weight was necessary.

One hint, however: The large WW2 hospital ships of the Germans had 400-500 beds, 2 operating rooms, x-ray room, special stations (ears, tooth etc.) etc. on 1oo+ts.

Regarding ratio staff/wounded - Gröner mentions 138/485 for the Hospital Ship (Lazarettschiff) C (Stuttgart) of 20500ts.

Hope this helps,

HoOmAn

Good to know.

I don't know if I'm lowballing the weight of the supplies or not. I'd think that even a tonne of drugs is a lot of drugs. Hard to say.

Interesting data on the German ships - a bit from the US Naval Historical Centre talks about a ~8,000 t ship carrying anywhere from 300 to 550 patients (the latter with some overflow into crew quarters), which was the basis for my own extrapolation. Your stats make me wonder if perhaps I've over-estimated the capacity of my 6,000 t ship...

According to Gröner smaller (<5kts) hospital ships carried about 120 wounded. That´s without an emergency scenario. Those ships only had 1 OR and were not equipped to deal with special diseases.

So I think 200 on a ~6.500ts units seems realistical. It depends on your navys medical standards, I guess.