Imperial Japanese Navy Kaibokan Type D, Class II
versus
USMC PBJ-1H Mitchell
USN 02 René Hieronymus Scale 1:72 Building time: approx. 700 hrs.
The history of the original and the story of the model:
In 1943 the Japanese influence in the Pacific region had already diminished noticeably. The first large sea - and land battles had been fought in favours of the U.S. armed forces, more and more islands in the central Pacific came into the scope of the US carrier-based aircraft carrier or land-based bombers. Especially the Japanese merchant fleet suffered under increasing losses, either by American submarines or aircraft.
The U.S. Navy continued to utilize land-based bombers which combined longer range and higher payload than carrier-based aircraft. However, this was only possible due to a "deal" with the USAAF which normally insisted on the sole use of land based bombers. But at this stage the USAAF was desperately looking for another assembly plant to produce the new B-29. The U.S. Navy on the other side had the brand new assembly plant for their new Boeing Sea Ranger in Renton. The Navy agreed to give this plant to the USAAF and the contract for this new flying boat was cancelled and in return the U.S. Navy received in the further future land-bomber like the B-25 Mitchell, as well as B-24 Liberators. Due to this deal, the U.S. Navy also benefited from such aircrafts and could use them for various purposes. In particular, the anti-submarine-warfare but also the long-range patrols were significantly improved.
Since Japan itself had no significant natural resources (this fact was one of the main reasons for the outbreak of war against the United States) with the exception of some coal deposits, due to this merchant shipping was crucial for Japan to bring these much-needed raw materials from the conquered areas to Japan. The only Means of transport in which this question was, were commercial vessels. Japan had to start war on a commercial fleet with a total of around 6.3 million tons of cargo space.
The Japanese Navy were afraid of losses of 900,000 tons annually, but this should be compensated by new buildings. Very early in the course of war this figure has been exceeded, however, already clear and from 1943, the losses among the Japanese merchant ships reached serious proportions. Between December 43 and February 44 about 650.000t tons of merchant ships were lost.
The general practice of the Japanese merchant ships to travel individually brought the great risk that these vessels in the case of a submarine or plane attacks usually were completely helpless and an easy target. The Imperial navy leadership only reluctantly accepted that the formation of convoys would have a contrary effect.
The officers of the Japanese Navy saw no "honourable" task in convoy escort service and simply refused to release valuable warships for such a mission, from their normal combat missions.
Only when the losses of merchant shipping assumed catastrophic proportions, they decided to build special Convoy-escort-ships, referred to as "Kaibokan", which freely translated "coastal defence vessel" or even "escort". These ship classes were developed so that its construction could be achieved by civilian shipyards, because the military shipyards were already fully utilized with new or repair work. These ships were built in 5 classes, the Type D Class 2, was the latest version. With a length of 69.5 m, a width of 8.6 m and a draught of 3.05 m this type had a displacement of max. 900t. Propulsion was provided by a geared turbine with 2500 hp and a range of 4500 nm at 14 kt. . Maximum speed was 17.5 kts . The crew consisted of 169 men. Armament consisted of 2 guns 12cm/45, and up to 12 x 25mm AA guns in single, double and triple mounts Type 96, an 80mm army type mortar and 120 depth charges.
From the beginning the Japanese placed great value on standardization of this ship type to achieve fast and simple construction. But even the Type D, the latest version of this class, could not prevent that American submarines and aircraft virtually brought an end to commercial shipping in Japan at the end of 1944. During the last year of the war the "Kaibokan’s” became easy prey to the ever increasing number of U.S. aircraft or submarines. Of a total of 171 units which were built until the end of the war 72 were sunk and most of the rest were damaged. The bulk of them by U-boats. Even so their main task was the protection of commercial vessels the Kaibokan were not able to fulfil this role in any way. From about 6.3 million tons of marine space, approximately 4.86 million tons were sunk, approximately 75% of the total Japanese merchant fleet! In return, the U.S. Navy lost "only" 26 U Boats in the Pacific Ocean. But the U.S. aircraft called their toll on the Japanese too. In particular, the PBJ-1 (B-25) which used the particular tactic of so-called "Skip-Bombing." This was a normal 250kg to 500kg Multi-purpose bomb which was dropped by the aircraft at high speed and a certain altitude close to the water. The bomb "jumped" from the water surface and hit a ship directly into the vulnerable side. In addition, the "Mitchell" used their own heavy machine guns to depress the enemies anti-air guns. The war in the Pacific was fought rigorously, it was even common practise to strafe survivors floating on the water surface after a ship had been sunk during an attack.
The North American PBJ-1 "Mitchell", (USAAF B-25) was an aircraft which was used in large numbers by the U.S. Navy and U.S. Marine Corps. Especially the later "H" and "J" versions gained some fame because of their heavy fire power and were frequently used as so called "Gunships". The Mitchell became famous, when several aircraft of this type were used in the famous “Doolittle Raid”. During this daring operation the aircrafts took of from the US Navy aircraft carrier USS Hornet to attack targets at the Japanese home islands. In the following years the Mitchell was repeatedly improved and particularly the number of machine guns grew steadily. In the "H" version she had no less than 14 heavy-caliber machine guns 0.50 (12.7 mm) and a 75mm cannon which was loaded manually and fired by the pilot. In addition the aircraft also carried bombs. The "H" version, however had some problems, particularly the pilot was overburdened, since he had to act as the pilot, co-pilot, which was in the “H” version omitted because of the additional weight of the big gun and as the bombardier at the same time. Additional the recoil of the big 75mm gun caused some serious problems with the planking, like cracks and other damage. In the subsequent "J" - version the gun was dropped and the cockpit had a co-pilot station again. Additional a glazed nose version was deployed again. However in the solid nose version the “J” version had no less than 18 .50 cal. Machine guns and with the new 5” HVAR the Mitchell had the firepower equivalent of a destroyers broadside.Furthermore, with the 5" HVAR missile a weapon with even more punch than the 75mm cannon was available. In addition, the "J" version had again a fuly glazed nose for a bombardier and the cockpit was reconverted for a co-pilot.
There were 7 squadrons being equipped with the PBJ: (VMB-453, VMB-463, VMB-473, VMB-483, VM-621, VMB-622, VMB-623 and VMB-624) they lost 45 aircrafts during the war, 26 of them were combat losses and 19 operational accidents. 173 crew members were killed. The PBJ-1/B-25 made itself a name due to its reliability and versatility and was even in use after World War II as trainer aircraf
General characteristics:
Engines: Wright R-2600-13, 14 cylinder radial engine air-cooled, 1700 hp.
Wingspan 20.59 m, overall length: 15.64 m (H), 16.30 m (J), Height: 4.98 m (H / J), Fuel capacity: (normal) 974 U.S. gallons (3,687 ltr.) Weight: 8,890 kg (H), 8.845kg (J).
Maximum takeoff weight: 15,876 kg (H / J). Maximum speed: 275mph at 13,000 feet (H)
277mph at 13,000 feet (J). Max. altitude: 23,800 feet (H), 24,300 feet (J). Crew: PBJ-1H: 5, PBJ-1J: 6, range with 1,361 kg bomb payload: 1,350 miles (H / J).
A major reason for the popularity of the PBJ-1 with their crews, was her enormous robustness. In particular, the two Wright-Cyclone R-2600 radial engines were in many cases a kind of insurance for a safe return. The use of air-cooled radial engines in the U.S. Navy had prevailed in the 20’s. This type of engines had the advantage of a lower weight and during the later years in the war became even more powerful than inline water cooled engines. Specially the reliability of these engines was legendary, more than once even badly shot up aircrafts brought their crews back home.
The diorama shows a PBJ-1H attacking a Kaibokan Type D, in the scale of 1:72. The construction of such dioramas requires a detailed planning, even before the start of the actual construction. Accordingly, a large number of books, magazines, videos and to a large extent, the Internet. And off course a lot of friends.
At the beginning, I had the idea of using the old Matchbox/Revell kit of the Flower Class as a basis for the Japanese submarine chaser. But as soon as I had a chance to inspect the kit closely it became obvious that this would not be possible, because the hull form of the Flower Class is totally different to everything the Japanese ever launched. So at the end I had no other choice than to build the ship scratch. Luckily a friend of mine had a book about Japanese warships of WWII and sure enough there was a set of plans in the book which turned out to be absolutely perfect for my use. The only I had to do, was to enlarge the plan to my scale, that way I was able to take any measurements directly from the plan, making the construction much easier.
The hull for my model was made as a composite construction consisting of a wooden skeleton which was covered with stiff cardboard. The frames were cut from extra-stiff cardboard and small wooden beams were used to form the inner hull. The bow as well as the stern were made from solid wood which was sanded into the appropriate shape. It took me only about 10 hrs. until the hull was finished and the main deck already in place.
The superstructure was made of cardboard and plastic sheet. The first details were added too. Some of them came from Floating Drydock one of my favourite dealers. The fittings from RH are pretty useful, some of them need additional details and have to be cleaned but overall I like them. The hawse pipes on the Forecastle were made as well other details in this area. The 12cm guns were entirely scratch build by using several self made parts as well as parts from other models, many of them definitely not ship related at all! One of them received an additional shield which was made of plastic sheet. Subsequently, the two guns were mounted onto their places at the bow and the stern of the shiip.
One of the biggest problems at this time was the deck planking. The Japanese used a diamond shaped pattern on this deck and so far I had absolutely no idea how to create something similar. The tripod mast was made of wood and plastic parts and assembled provisionally. However, during the next few weeks I made several improvements to the mast because more and better photos became available. The interior of the bridge was also detailed, steering wheel, compass, Pelorus and so on were installed, as well as the window frames and on top of it the open bridge with various parts such as the gun director and several binoculars. The smokestack was built from a solid piece of wood which was carved and sanded. Meanwhile, the work expanded on the centre and aft ship. The deck house was made entirely of plastic sheet, including the railing and the two platforms where later the two 25mm triple AA guns were mounted.
A small kit for itself was the searchlight which I made from a tiny plastic box and the help of some tiny bits and pieces from various kits. The inside of the bow which was supposed to become the actual search light was covered with bar metal foil. After that the whole thing was installed onto a small structure which in turn was mounted atop the deck house.
The wooden for the smoke stack was covered with thick aluminium foil from various tubes and brought to its final form with some other small parts. Even the tripod mast received a few more details, such as the small radar, which looks like a pair of loudspeakers.
Since most of the main parts of the ship were finished, I could start the final detailing. Numerous tiny parts were attached to the model, 2 of the 3 life boats were robbed from the Flower class kit, the third came from a company named “Krick”, some additional details and the self made davits to which they were attached. The entire depth charge roller tracks and the Japanese version of the “K-guns” on the stern were build, detailed and assembled. The ready ammunition lockers for the 25mm AA guns caused some small headaches. Mostly because I had to make several of them. The AA guns themselves proved to be no really problem. With the help of some kit bashing I was able to build those guns in single, double and finally a triple version quite easily. The barrels came from a German 20mm quad gun which turned out to have almost the same proportions and needed only a few more details to make them look more “Japanese”.
At about this time a friend of mine surprised me with something what he called “this could work” substitute for the deck planking. A few days later I saw what he had found and to make a long story short, THAT was exactly what I was looking for. The thing he had found was diamond shape pattern plastic sheet made by PLASTRUCT. All I had to do was to cut those sheets in the right sizes and shapes and attach them to the deck levels. I wished everything could be just as easy as this turned out.
Finally it was time for some colour! The entire model was primed in dark grey which was almost looking like the final colour. This way the final weathering is something easier. Dry brushing was used for this. Due to the fact that most of these ships did not enjoy a very long service life I kept the weathering very small.
Out of curiosity, I tried to calculate the number of parts which I had used for the entire model and came up with a whooping 1.800 parts.
After the whole ship was painted, it started with the figures. For this I used mostly Preiser figures, as well as the heads of Japanese soldiers from Heller / Airfix which a friend of mine casted for me.
Contrary to building of the ship there is not much to say about the construction of the aircraft model. For this I used the Italeri kit of the B-25H Mitchell. This was one of the few occasions that I used a couple of aftermarket parts namely the PE sets from Eduard. The basic kit from Italeri is sadly not the best but at this time it was besides the one from Airfix the only one available. To improve the kit I had to add a couple of additional parts. The Eduard PE parts are pretty good and pretty expensive if compared to the cost of the aircraft kit! Besides of that I have some problems with the fact that some of the PE sets are wide of the mark! In this PE set for example the instruction tells you to install a new seat for the co-pilot, which is simply completely wrong. Contrary to some publications the “H” version had NO co-pilot at any time and there was no seat installed or station for him inside the cockpit. This and some other parts from this PE set which are either completely wrong or simply not included even if they were clearly visible from the outside of the model! The place where I could use them to the best effect was the open bomb bay.
But to be honest I do not like these kind of aftermarket sets very much. To me it looks as if today’s model builder becomes more and more a model-assembler. Sure with the help of these parts and sets it has become possible for most model-builders to create outstanding detailed models but on the other side, it looks as if scratch building has become outdated. When I started to build my first model, many years ago it was absolutely necessary to learn those skills because there were no aftermarket parts available at all. So if someone wanted to build a special version of an aircraft you had to make those parts by yourself. And off course these special skills will be very helpful in any other model-building-project, no matter if you like to use after market parts or not. So today it is no wonder that I personally tend to make my own “aftermarket parts” by simply using these, what I call “basic-skills”, instead of buying some in most cases grossly overpriced bits and pieces which in some cases are not correct as well.
Finally the model was painted in the appropriate camouflage. Some stars and bars and a serial number were the only decals which this kit needed. A little bit weathering and off course the “special device “ to make the aircraft “flying”. For this I had inserted a small metallic tube inside the port wing which ended right at the wingtip. Later the entire model would be simply slipped onto a metallic rod which is in turn fixed at the base of the diorama and hidden inside the rising water column made of cotton.
The diorama base itself is a pretty simple story. I used a lightweight wooden board with a frame 1,20m x 1,60m large. The frame was stained and later polished. The “water” was made in my favourite way. Over the years I had the chance to build several dioramas and whenever possible I tried several different techniques for a certain problem. For water I have finally settled for the following way which in my opinion is the most effective and simplest way to achieve the desired result. I use ordinary toilet-paper and wall paper glue. This products are (hopefully) available everywhere and most of all cheap! All I do is, I start soaking the entire base with the exception of the place where the ship will be added later. The toilet paper is added to this surface layer after layer, each is being soaked with lots of glue. Wherever there will be a wave I simply add more paper and some more glue. That way the entire base was formed and build. Finally a wave pattern for the ship was created either by suing an old brush or your fingers. I simply shove the paper in the desired form and that’s it. As soon as the glue starts to dry these waves can further detailed by reforming them. Depending on the number of layers of paper and the amount of glue used it can take several days until the entire “water-base” is completely dry.
At this point I started to colour the whole thing, I like to use a mix of water colours, acrylics and some time even oil colours for this. As long as the colours like lifelike everything is allowed. For the water columns I used ordinary cotton, which was simply formed, thoroughly sprayed with hair spray or lots of Future. This makes them a little bit stiffer and easier to glue them to the base. The large column was additionally slightly coloured at the base to make it look more realistic. Inside this column I installed the brass rod which will hold the aircraft “up in the air”
The total building time for this entire project was almost exactly 780 hrs. or 1 year
And my final conclusion: A lot of work, but a lot of fun as well. Building your own ship like this is much simpler than most people would think. Sure it might be easier to use a kit and simply follow the instructions but anybody who wants to do something new, challenging and entertaining give it a try and have fun with it!
Sources literature:
The Pacific War Atlas - D. Smurthwaite, Warpath across the Pacific; The Imperial Japanese Navy Vol.I; Warships of the Imperial Japanese Navy 1800-1945, Jentschura, Young & Mickel;
U.S. Navy Air Combat, R. Lawson & B. Tillmann; U.S. Naval Airpower, R. Lawson; Pacific Air War, C. Campbell; Warship Vol VII, Naval Institute Press; Naval Weapons of WWII, J. Campbell; across the warpath Pacific, LJHickey; Koku fan - several spending; Internet.
Sources photos:
Unless otherwise noted from my own collection.
Off course there are quite some people to which I have to say thank you very much for their help, support and patience:
First of all, my wife, thank you for being so patient with me, thank you for your understanding that I had to do this, and most of all thank you very much for loving me!
Some other people to which I have to say thanks:
Otmar I, for the books and THE PLAN, Wolfgang for THE “could work parts”, Othmar II for the heads, Harald for a plan that started everything, Tom for his constructive criticism prompting me to do it better every time, Mr. Fial for not loosing his patience when I asked him for some of his catalogues to look at, and finally Albert for those fantastic photos!
Keep on modelling
René Hieronymus
www.usns.biz
Bürmoos, January 2002