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Old 02-13-2016, 04:25 PM   #1
Engurrand
 
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Default PBY Catalina and Combat Examples

I've got a group of characters tooling around the Mediterranean in a PBY Catalina (stats link, more stats, photo, photo) In preparation for the inevitable, I've been working out the airplane's stat block. In a further effort to frontload the math, I decided to run some sample combat scenarios to familiarize myself with the kinds of penalties I'll be seeing. I'll post those as soon as I've finished them.

Disclaimer: I am a neophyte in the nerdome of WWII hardware. It is an epic nerdom. I'm taking my first steps into a larger world. Corrections, suggestions etc are always welcome.

Disclaimer the second:
Many of the relevant GURPS rules were a little difficult for me to parse. I may have been particularly creative in working out the hit location table. Corrections suggestions yadda yadda.

Consolidated BPY-5A Catalina, USA, Canada, USSR, 1940-1945
The first production model PBY Catalina rolled off the assembly line in September of 1936, one of fifty ordered by the US Navy to serve as long range patrol planes. By the end of the war the total number grew to around 3,300 and the Catalina had seen service under dozens of flags and in every theater of the war.

In 1937 one model, dubbed NCC 7777 "Guba" was sold to the stupendously named Dr. Richard Archbold who used it for explorations in New Guinea and the first seaplane transcontinental flight before selling it to the USSR. The similarly excellently named Sir Hubert Wilkins used one to try to find a lost arctic expedition (photo).

The listed model is a PBY-5A which has three wheels which retract and two float pylons which fold up to serve as wing-tips. Earlier models lacked the blister turrets and wheels (they could land only on water). This model and later ones may replace the wheels with removable gas tanks: This reduces Load by 1.3, but increases Range by 500.

Military models have six fold-out bunks, a galley, a chemical toilet and a radio. Crew includes Pilot, Co-pilot, Navigator, Radio operator, Nose gunner/bombardier, 2 blister gunners, 1 ventral gunner, and a flight engineer. Cost is $1,500,000. Armament was typically two MG34 [Ht134] machine guns in the nose and one in the ventral turret, plus one Browning M2HB machine gun [Ht133] in each "blister" turret. Variations from this armament were common. Hardpoints under the wings carried up to 2 tons of bombs a/o torpedoes, or four 325 pound depth charges. Late war models add radar and a radar operator crewman.

Civilian models were employed as airliners. These were crewed by three: Pilot, Co-pilot and steward(es). 14 passengers in the cabin, replace blister turrets with small windows, no nose turret.

In 1950 a handful were modified to serve as flying yachts under the brand Landseaire (extensive photo blog). These are Styling x2 and include a radio phone, hot shower, full bar, plus the galley has a stove and refrigerator and one hardpoint stows a rowboat. Crew is 2+6(?)A Cost is $2,300,000.

Models continue to be used for firefighting and sea patrol to this day.

The Catalina's versatile landing capabilities, long range, living space and (potential) armament make it a good candidate to serve as your pulp adventuring group's Millennium Falcon (though it won’t be outrunning anything, let alone an imperial cruiser unless that’s a blimp).

Code:
TL	Vehicle		ST/HP	Hnd/SR	  HT	Move	LWt.	Load	SM	Occ.	DR	Range		Cost		Locations	Stall
6	Catalina	110	-2/3	  12	3/98*	17.7**	2***	8	9A	3	2,520†		$1,500,000	g,rR2,rW,Wi,t4	33
*If you prefer realism over GURPS approximations, the Catalina's rated optimal cruising speed at 70% power is 137 KIAS = 157 mph = roughly 67yards per second. It's top speed is 137 KIAS = 197mph = 98 yards per second.
**This is the Max takeoff weight from wheels. The LWt is 17.25 when taking off from water, and 13.65 from rough water.
***This is Load when taking off from wheels. Water liftoff Load is 1.5. Rough water liftoff Load is -2. The negative (-) is not a typo. To lift off from rough seas the pilot is obliged to dump a weight of fuel (and/or gear, people etc) equal to 2 tons + the weight of remaining occupants and cargo. The Catalina’s max fuel load is 5 tons so this will severely adversely affect range.
† The longest recorded flight was from Perth Australia to Colombo Sri-Lanka, 4133 miles!

Hit Location Table:
Note: I’ve factored the airplane’s SM into the To Hit bonuses.
Code:
 

Roll	Location 		To Hit	Notes									HP
3-4	Cockpit			+1	Check if occupant hit, on hit, damage is to occupant not vehicle	
5	Nose Gun		+3	HP wounds causes destruction, excess lost.				37	
6-7	L Wing			+6	HP wounds causes destruction, excess lost. Fragile (Combustible)	55	
8	L Blister		+5	Check if occupant hit, on hit, full damage is to occupant not vehicle.		
9-11	Body			+8	Check if occupant hit. Occupants take 1d per full 5 wounding to vehicle		
12	R Blister		+5	Check if occupant hit, on hit, full damage is to occupant not vehicle.		
13-14	R Wing			+6	HP wounds causes destruction, excess lost. Fragile (Combustible)	55	
15	Runner			+4	HP wounds causes destruction, excess lost.				34	
16	Wheel			+4	If retracted count as body hit.						18	
17	Engine, Left		+5	Tight beam wounding x2, piercing x3, fragile (combustible).
					HP wounding causes destruction and fire, excess lost.			50	
18	Engine, Right		+5	Tight beam wounding x2, piercing x3, fragile (combustible).
 					HP wounding causes destruction and fire, excess lost.			50
To check if occupant is hit, roll 3d against the below number. Notation is: “Number of current occupants (occupant is hit on roll of).” GM may determine which occupant is hit either by fiat or randomly.
Code:
1 (3), 2 (4), 3-5 (5), 6-10 (6), 11-20 (7)
Additional Notes:
Cockpit Window – I’ve decided to treat this as a small window.
Blister Guns – After reading through the game mechanical definition of a turret, I decided these were more like big windows with a gun on. Damage to them which doesn’t hit the gunner should be treated as body damage, not destroy some of the turret’s functionality as the entry for Main Turret, nor destroy the turret but not damage the body, as the entry for Small Turret.
Engines – Because the engines are both vital, and separate from the body by a support structure, I’ve decided to give them their own HP pool like a limb, but apply the wounding of a vitals shot. Note that the fire of a burning engine (1d+1 per second) may spread to a wing once it’s done enough damage. If this starts to happen it is advisable to land immediately.

Combat examples I'm working up:
Strafing of stationary ground target.
Bombing run of stationary ground target.
Air to Air Engagement vs FW-190.

Edited to correct the handling bonus from +1 to -2, fix errors with model number and production period, and improve some text.
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Last edited by Engurrand; 02-14-2016 at 04:30 PM.
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Old 02-14-2016, 04:31 AM   #2
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Default Re: PBY Catalina and Combat Examples

Quote:
Originally Posted by Engurrand View Post
Combat examples I'm working up:
Strafing of stationary ground target.
Bombing run of stationary ground target.
Air to Air Engagement vs FW-190.
I am not expert in using the vehicles mechanics, but a historical Catalina has no business doing any of these things. It's a large and very slow aircraft, acutely vulnerable to ground fire and land-based fighters. Its place is over the ocean, where the AA is mostly confined to the light weapons of hostile submarines, staying out of range of land-based fighters and away from carrier-based ones.

If you want your PCs doing bombing and strafing over land in the MTO, they'll do better if you switch them to a North American B-25, Martin B-26 or Douglas A-26. A way to finesse the transition might be the use of the B-25 as a maritime patrol aircraft, as the PBJ-1.
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Old 02-14-2016, 05:58 AM   #3
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Default Re: PBY Catalina and Combat Examples

One trick I think you're missing: Top Speed is listed in terms of Move, i.e. yards per second. p. B466 calculates Cruising Speed in miles per hour so that you can work out how many hours it takes to go a set distance. 1 yard/second is roughly 2 mph. So what that rule is actually saying is that aircraft cruising speed is about 78% of top speed, and if you want to use that last 22% you pay the fuel penalty.
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Old 02-14-2016, 08:30 AM   #4
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Default Re: PBY Catalina and Combat Examples

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Originally Posted by RogerBW View Post
One trick I think you're missing: Top Speed is listed in terms of Move, i.e. yards per second. p. B466 calculates Cruising Speed in miles per hour so that you can work out how many hours it takes to go a set distance. 1 yard/second is roughly 2 mph. So what that rule is actually saying is that aircraft cruising speed is about 78% of top speed, and if you want to use that last 22% you pay the fuel penalty.
Ah. Thank you for that clarification. Then the Catalina's top speed should be listed as 93 and is not quite so poorly named as I had thought. Though it's cruising speed is not, in this case, 78% of it's max speed, it's a close enough approximation. I'll edit the above to reflect that. Cheers.
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Old 02-14-2016, 09:10 AM   #5
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Default Re: PBY Catalina and Combat Examples

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Originally Posted by Engurrand View Post
Consolidated BPY Catalina, USA, Canada, USSR, 1936-1945

Military models have six fold-out bunks, a galley, a chemical toilet and a radio. Crew includes Pilot, Co-pilot, Navigator, Radio operator, Nose gunner/bombardier, 2 blister gunners, 1 ventral gunner, and a flight engineer. Cost is $1,500,000. Armament was typically four Browning M2HB machine guns (Ht133), one in the nose, one in each "blister" turret, and one in the rear ventral position. Hardpoints under the wings carried up to 2 tons of bombs a/o torpedoes, or four 325 pound depth charges. Late war models replace the nose gun with two 7.62 machine guns, and add a radar operator to the crew.

Code:
TL	Vehicle		ST/HP	Hnd/SR	  HT	Move	LWt.	Load	SM	Occ.	DR	Range		Cost		Locations	Stall
6	Catalina	110	-2/3	  12	3/43*	17.7**	2***	8	9A	3	2,520†		$1,500,000	g,rR2,rW,Wi,t4	33
*This number is arbitrary. By raw [B466] an air vehicle’s cruising speed is 1.6xTop Speed, and its max speed is 2xTop Speed. The Catalina’s cruising speed should be 62 and top speed 93 so that would make its particularly ill-termed game “Top Speed” either 39 or 47 (rounded). I picked the mid-point but I prefer to use the actual cruse speed and top speed, as those are known.
**This is the Max takeoff weight from wheels. The LWt is 17.25 when taking off from water, and 13.65 from rough water.
***This is Load when taking off from wheels. Water liftoff Load is 1.5. Rough water liftoff Load is -2. The negative (-) is not a typo. To lift off from rough seas the pilot is obliged to dump a weight of fuel (and/or gear, people etc) equal to 2 tons + the weight of remaining occupants and cargo. The Catalina’s max fuel load is 5 tons so this will severely adversely affect range.
† The longest recorded flight was from Perth Australia to Colombo Sri-Lanka, 4133 miles!
What version of the catalina are you trying to do?

The PBY-5 and 5A (1940-43) had top speeds of 196 mph that is move 98.

The typical ranges given for it are the 2500 miles at about 125mph. The top speed burns a lot more fuel, not the +50% given in campaigns.

The very long range flights like the Perth Australia to Colombo Sri-Lanka are achieved by traveling at only slightly over stall speed further reducing fuel use.

A more typical armament for such is 2-3 .30 MGs(1-2 frontal+ventral) and 2 .50 MGs(sides). But there was a big variation.

Quote:
Combat examples I'm working up:
Strafing of stationary ground target.
Realistic:
You approach a ground target in your slow, large and not very agile target.
Anti-air defenses shoot you down.

Semi-Cinematic: There are no anti-air defenses except something like ground troops with light machine guns and rifles:
You circle at long range and fire one of your side .50 cal staying out of the effective range of the ground fire. It will be all suppressive fire.

Quote:
Bombing run of stationary ground target.
Realistic:
As above against most types of targets.

Really out of the way places with limited air defenses might allow high altitude bombing attacks with only a fairly high probability of being shot down. Going down where light AA can hit is suicide in such a slow clumsy target.

Semi-Cinematic: On targets other than cities and other well defended areas that would have radar:
You approach in the clouds using cinematically good navigation skill to be near target and quickly drop out of clouds, drop your bombs and go back to the clouds before the defenders can react.


Quote:
Air to Air Engagement vs FW-190.
Realistic:
The FW-190 pilot is good: The FW-190 comes from below or other dead angle and shoots the catalina down.
The FW-190 pilot is not so good: FW-190 approaches from front and you can use your frontal single or dual .30 cal to try to hit the agile target before he uses his canons to rip you apart.

Semi-Cinematic: the FW-190 comes from behind, giving you longer time to try to hit it and allowing the pilot to twist the catalina to allow the defense to be from a .50 cal, giving a small chance of success. Basically the catalina would likely open fire at (much) longer range than the FW-190 and hope for the near impossible hit before the FW-190 is close enough to want to fire(it has low number of cannon shells so wants to hit with most). Then using the cinematically good gunner skill to shoot down the FW-190 as it approaches.
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Old 02-14-2016, 09:48 AM   #6
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Default Re: PBY Catalina and Combat Examples

Quote:
Originally Posted by weby View Post
Realistic:
You approach a ground target in your slow, large and not very agile target.
Anti-air defenses shoot you down.
Or:
http://pwencycl.kgbudge.com/P/b/PBY_Catalina.htm

Black Cats. A handful of PBY-5A Catalinas equipped with early ASV radar had reached the Pacific by August 1942 and participated in the Battle of the Eastern Solomons. In December 1942, the Americans deployed a full squadron of PBY-5As to operate at night in the Solomon Islands. This "Black Cat" squadron (VP-11) painted its aircraft black, except for a squadron insignia that started out as a basic cat outline. Eyes were added after the second mission, teeth and whiskers after the third, and, allegedly, "anatomical insignia of a more personal nature" after the fourth mission (Morison 1949). The Black Cats participated in search, strike, and gunfire spotting missions, taking off at about 2230 each night and returning after daybreak. Over time, other squadrons began flying Black Cat missions, and Creed (1985) claims most of the squadrons in the South and Southwest Pacific had rotated through Black Cat tours by the end of the war.

The Catalinas proved well suited for these missions. The black paint and the flame dampers that were later installed over their exhaust ports made them all but invisible in the darkness. If a Japanese night fighter did locate a Black Cat, the Catalina would drop to very low altitude, where it was almost impossible for a night fighter to engage without crashing into the sea. This tactic was aided by radar altimeters installed on most of the Black Cats. The radar altimeters also allowed the Cats to fly the last 100 miles (160 km) to their targets at 50' (15 m) altitude to evade radar. The slow speed of the Cats was actually advantageous for night attacks at mast height.
Initially, the Cats dropped illuminating flares before attacking, but this proved counterproductive. Torpedoes also proved ineffective because of their unreliability. Eventually the tactic that was settled on was to locate targets by radar, then visually, before attacking from the quarter with a salvo of four 500 lb (227 kg) bombs with 5-second-delay fusees dropped from 50 to 150 feet (15 to 45 meters) altitude. A flare was sometimes dropped with the bombs to blind enemy gunners, and some Cat crewmen tossed parafrag bombs from the blisters or ventral hatch to further suppress antiaircraft fire. The gunners held their fire until the bombs were released to further increase the element of surprise. Black Cat search missions in the Solomons included "Mike Search", a three-hour course up "The Slot" and through Indispensable Strait between Santa Isabel and Malaita. Three circuits could be flown in a single night. By August 1943 the Cats were flying "ferret" missions with electronic warfare technicians to locate Japanese radar installations for later air strikes. A number of Cats in the Southwest Pacific were field modified with four 0.50 machine guns in the nose, turning them into potent strafers and making them highly effective at night barge hunting.
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Old 02-14-2016, 10:02 AM   #7
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Default Re: PBY Catalina and Combat Examples

The thing is, against the Japanese the tactic worked because of the lack of radar. Around the Mediterranean where the OP is placing things the probability of eventually being too close to some place with air defense radar is high and then night will not help that much.

It should also be noted that the Germans had on average more anti-air capability included in their ground forces than the Japanese.
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Old 02-14-2016, 12:04 PM   #8
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Default Re: PBY Catalina and Combat Examples

Quote:
Originally Posted by weby View Post
What version of the catalina are you trying to do?
This one. Which is the 5-A.

Quote:
Originally Posted by weby View Post
The PBY-5 and 5A (1940-43) had top speeds of 196 mph that is move 98.
I detect a rounding error on my part. Fixed. Thank you!

Quote:
Originally Posted by weby View Post
The typical ranges given for it are the 2500 miles at about 125mph. The top speed burns a lot more fuel, not the +50% given in campaigns.

Yes. 2,520 miles at move 63, to be precise. How much fuel is burned at top speed is not clear to me. For simplicity's sake, halving range at top speed makes game sense.

Quote:
Originally Posted by weby View Post
The very long range flights like the Perth Australia to Colombo Sri-Lanka are achieved by traveling at only slightly over stall speed further reducing fuel use.
Interesting! and potentially important to know for those emergency long distance flights.

Quote:
Originally Posted by weby View Post
A more typical armament for such is 2-3 .30 MGs(1-2 frontal+ventral) and 2 .50 MGs(sides). But there was a big variation.
I noted that in my research, but considering the variance I decided to go for the simpler set. In my actual game I've got it loaded with one Browning in the nose and one MG37 in each blister.

Quote:
Originally Posted by weby View Post
Snip snip...

Realistic: ...snip snip

Semi-Cinematic: ..snip snip
Yours are the results I've discovered in running the game math. I've just got my excel sheet sorted out, so standby for actual numbers. In brief: Heroes can shoot stationary ground targets, but their attack ranges must be close enough such that they would stand no chance against AA guns. Minions have a low chance of success even at close ranges. It should be possible to improve these odds to a degree by adding MOAR GUNS, but since the AA can do the same and they will almost always be bigger, you should not play chicken with AA guns in a Catalina. Not on purpose, anyway. Actually, do not play chicken with AA guns is a good flight rule no mater what you're flying. Right up there with do not argue with the ground.

Incidentally, how is suppression fire game mechanically better than targeted shooting? By my reading of the rules, it still suffers range/speed penalties. Am I wrong?

I have not started on the bombing rules yet.

Against an attacking aircraft, the Catalina Pilot's job is to present her defensive gun(s) to the enemy when that enemy turns nose on target to fire (dropping relative speed to 0). From my watching of documentaries, this may happen at surprisingly short ranges, such that hits from the defensive guns are possible, though the Catalina is unlikely to survive the exchange with a much more heavily armed FW190. Especially where the Catalina's vehicular dodge gives its gunner -4, and the pilot of the FW190 can dodge at no penalty to their attack!
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Old 02-14-2016, 12:09 PM   #9
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Default Re: PBY Catalina and Combat Examples

Quote:
Originally Posted by weby View Post
The thing is, against the Japanese the tactic worked because of the lack of radar. Around the Mediterranean where the OP is placing things the probability of eventually being too close to some place with air defense radar is high and then night will not help that much.

It should also be noted that the Germans had on average more anti-air capability included in their ground forces than the Japanese.
Hmm... we're in 1937 so no radar yet. But could WWII era radar detect you at mast height? I was given to understand it would have some trouble, but maybe over the ocean? Not sure. Will research.
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Old 02-14-2016, 12:11 PM   #10
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Default Re: PBY Catalina and Combat Examples

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This is very cool and exactly the sort of thing a group of PCs would get up to. Thank you!
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