IJA Landing Operation Ships with slopes at the stern

Discussions on all aspects of the Japanese Empire, from the capture of Taiwan until the end of the Second World War.
User avatar
fontessa
Member
Posts: 4511
Joined: 25 Mar 2011 16:29
Location: Yokohama, Japan

IJA Landing Operation Ships with slopes at the stern

Post by fontessa » 30 Jan 2022 02:14

特種輸送船 Special Transport Ship 神洲丸 Shishu Maru
fontessa wrote:
13 Jan 2022 18:21
Yes, "the slope of the stern" was a specialty of Japan.
Do you know 神州丸 Shinshu Maru? She could launch many Dihatsu rapidly using the slope of the stern. IJA built her in 1934 when the United States and Britain never thought about it.

fontessa


IJA conducted a landing operation in front of the enemy during the 1st Shanghai Incident in 1932 and experienced great difficulty in transporting landing craft and landing soldiers’ boarding on landing crafts. Therefore, IJA came up with the idea of a "Landing Craft Mother Ship" that could store landing craft in a hold and launch them with landing soldiers onboard. By doing this, it was possible to avoid the dangerous embarkation of landing soldiers on the landing crafts and shorten the operation time. It was an idea unlike any other in Europe and the United States.
In 1933, IJA outsourced the design of "特種輸送船 Special Transport Ship" to IJN. 艦政本部 Naval Shipping Administration Headquarter was in charge of the design. It's unprecedented, so several changes were made until the design was finalized. That is why FIGs. 1 and 2 are slightly different. The core part is shown in FIG2, trolly wire pulled by the winch pulled Daihatsu on wooden stands from the storage position to the launching position. There were two slopes, and two Daihatsu could be launched at the same time, as shown in FIG3. The two slopes were not parallel and faced outwards, so 2 Daihatsu that launched at the same time, did not collide. A 泛水作業隊 Launching Unit was formed from one platoon of 6th Independent Shipping Engineer Regiment to carry out these launch operations. The cecomposition of the Jinshu Maru Launching Unit was as follows;
隊長 Commanding Officer: 1
伝令 Messenger: 1
衛生 Medic: 1
前部甲板分隊 Forward Deck Squad: 15 men
後部甲板分隊 Rear Deck Squad: 14 men
端艇甲板左舷分隊 Port Boat Deck Squad: 9 men
端艇甲板右舷分隊 Starboard Boat Deck Squad: 9 men
中甲板左舷 Port Middle Deck Squad: 9 men
中甲板右舷 Starboard Middle Deck Squad: 9 men
艉門左舷 Port Rear Door: 9 men
艉門右舷 Starboard Rear Door: 9 men
合計 Total: 86 men

This “Special Transport Ship" was constructed in 播磨造船所 Harima Shipyard and commissioned in 1935. She was named 神洲丸 Shinshu Maru, but she was completely concealed - even attached the battleship Hyuga's No2 funnel which was no longer needed due to the refurbishment, to hide the existence of the hangar. Because what IJA wanted to hide most was that she had the ability to operate airplanes. Therefore, the IJA disguised her hangar as "a place to keep horses" and called the hangar deck "馬欄甲板 Stable Deck". But, like the Hrikeens of MAC ships, they could not land on Shinshu Maru. Her unique appearance caught the attention of the US Navy, and close-up photos like her FIG4 were also taken.

Her brief performances were as follows;
Standard Displacement: 7,100t
Full Load Displacement: 8,108t
Size: 144m (Length) x 22m (Width) x 4,2m (Draft)
Maximum Speed: 20.4kt
Cruising Range: 7,000 nautical miles
Standard Capacity: Approximately 1,200 men (Maximum 2,000 men)
Standard Load: Daihatsu x 30, Shohatsu x 20
Maximum Airplanes Carried: 12

Shinshu Maru participated in many landing operations in China. The first battlefield entry of her was the transportation of part of the 10th Division, which was temporarily mobilized during the outbreak of the Sino-Japanese War. FIG5 shows her with a large number of landing crafts during the Bias Bay landing operation in 1938. She was seen by Americans and the pictures were taken by them. FIG4 was one of the photos.
Landing operations participated before the start of the war;
太沽 Dagu: August 14, 1937
川沙 Chuansha: August 23, 1937
松江 Songjian: September 1, 1937
杭州湾 Hangzhou Bay: November 5, 1937
バイアス湾 Bias Bay: October 12, 1938
広東湾 Guangdong Bay: October 22, 1938
東京湾 Gulf of Tonkin: November 15, 1939
北部仏印 Northern French Indochina: September 1940
南部仏印 Southern French Indochina: July 1941

She was used in the Dutch East Indies Campaign even in the early days of WWII. Here, torpedoes fired by Mogami targeting USS CA Houston hit Shinshu Maru and other Japanese ships on the extension of the line of sight, and the 16th Army Commanding Officer and other HQ personnel on board have fallen into the sea on 1 March 1943. Because of the shallow waters, she was pulled up and returned to service in November 1943 with emergency repairs at the 101st Naval Construction and Repair Department in Singapore and complete repairs at the Harima Shipyard. However, due to the deterioration of the war situation, she could not be put into the landing operation, and she was engaged in transportation missions with Hi-57, HI-65, HI-81, HI-85, TAMA-33, TAMA-38, and MATA-40, etc. On her last voyage with MATA-40, she was sunk by USS Aspro, S / AG SS-309 torpedo attack on 3 January 1945.


上陸 神洲丸 外観 1.jpg

上陸 神洲丸 図面.jpg

上陸 神洲丸 外観 3.jpg

上陸 神洲丸 外観 4.jpg

上陸 神洲丸 外観 2.jpg

fontessa
You do not have the required permissions to view the files attached to this post.
Last edited by fontessa on 30 Jan 2022 03:55, edited 2 times in total.

User avatar
fontessa
Member
Posts: 4511
Joined: 25 Mar 2011 16:29
Location: Yokohama, Japan

Re: IJA Landing Operation Ships with slopes at the stern

Post by fontessa » 30 Jan 2022 02:18

HMS Stern Chute Landing Ships (LSS)

Royal Navy had two landing craft transport ships - Princess Iris and Daffodil. They were originally built as train ferries for the Strait of Dover and charged to Royal Navy twice, in 1917 and 1940. In WWI, they engaged the train transportations in the Strait of Dover as HMS Train Ferries No1 and No3. After WWI, they were dismissed from Royal Navy and continued to train transportations in the Strait of Dover at the railroad company. In the 2nd charge to Royal Navy, they were refurbished to landing craft transport ships, Stern Chute Landing Ships (LSS). FIG1 shows Stern Chute Landing Ships (LSS). It looks like she has the same concept as Shinshu Maru. Royal Navy may have devised it. Or it may be that Royal Navy referred to Shinshu Maru, which had been conducting several landing operations in China before 1940. FIG2 shows the photos of HMS Train Ferry No1 and HMS Princess Iris. It is clear that she was too small to use in "continental counterattack". Some redesigns were needed. I don't think Royal Navy which had to deal with the expected German army on a daily basis, afforded redesigns. And it was LSD - tank landing craft transport ship that Britain proposed to the United States for the "continental counterattack", not LSS - personnel landing craft transport ship.

The brief performances of HMS Princess Iris were as follows;
Full Load Displacement: 2,683t
Size: 106.9m (Length) x 17.85m (Width) x 3.4m (Draft)
Flight Deck Length: 120m
Flight Deck Width: 21m
Maximum Speed: 15.5kt


上陸 作戦艦艇 HMS Princess Iris 1.jpg

上陸 作戦艦艇 HMS Princess Iris 2.jpg

fontessa
You do not have the required permissions to view the files attached to this post.

User avatar
fontessa
Member
Posts: 4511
Joined: 25 Mar 2011 16:29
Location: Yokohama, Japan

Re: IJA Landing Operation Ships with slopes at the stern

Post by fontessa » 30 Jan 2022 02:23

USS Attak Transport Ships (APA)

USS Transport Ships (AP)
U.S. Navy started the building of personnel transport ships categorized as AP around WWI. FIG1 shows USS Henderson (PA-1). This photo was taken at Coco Solo, Panama Canal on 6 January 1933. Note she didn’t carry landing crafts. I think U.S. Navy put landing crafts into practical use after the mid-1930s.

USS Attack Transport Ships (APA)
U.S. Navy renamed AP to landing operations ships were categorized as APA (Attack transport Ship) in January 1943, perhaps after carrying of landing crafts became normal.
They were from USS Doyen (APA-1) to USS Glynn (APA-239). Not all 239 ships were built because of the vacant numbers, but it's a terrifying American industrial power. I feel Japan has quarreled with a country that was too powerful.
FIG.2 shows USS Heywood (AP-12) taken in 1941. She carried landing crafts and had derricks for moving landing crafts to the sea surface. FIG.2 also shows USS Heywood (PAP-6) taken in 1944. As shown in the same picture, the landing soldiers must have boarded landing crafts along with the net. As shown in FIG3, the transfer method of these landing soldiers was the same through WWII, even in Korean War. It was dangerous and time-consuming. IJA who experienced the landing operation in the same way for the 1st Shanghai Incident in 1932 thought so and felt the need for improvement. Shishu Maru was the conclusion of the improvement.

USS Tank Transport Ship (LSD)
U.S. Navy built 25 dock-type landing ships (LSD-1 〜 LSD-25) based on British ideas in WWII. They transported and launched LST tank landing crafts housed in the dock. LSD-9 〜 LSD-12 were transferred to Royal Navy. FIG4 shows USS Gunston Hall (LSD-5). After the war, LSD transported and launched hovercraft. The dock-type landing ships have undergone various improvements after the war and now reached to San Antonio class LPD shown in FIG5.


上陸 USS Henderson (AP-1).jpg

上陸 USS Heywood (AP-12 APA-6).jpg

上陸作戦 米軍.jpg

上陸作戦艦艇 USS Gunstor Hall (LSD-5).jpg

上陸作戦艦艇 USS San Antonio (LPD-17).jpg

fontessa
You do not have the required permissions to view the files attached to this post.

User avatar
tom!
Member
Posts: 888
Joined: 15 Dec 2003 11:42
Location: Dorsten Germany

Re: IJA Landing Operation Ships with slopes at the stern

Post by tom! » 30 Jan 2022 12:27

Hi.

Didn´t the other IJA landing craft carriers (Ko-, Otsu-, Hei-Type) also had this stern ramp mechanism?

Yours

tom! ;)

EwenS
Member
Posts: 457
Joined: 04 May 2020 11:37
Location: Scotland

Re: IJA Landing Operation Ships with slopes at the stern

Post by EwenS » 30 Jan 2022 14:04

Throughout the inter-war period Britain experimented with a number of small landing craft types. This culminated in 1938 with setting up of the Inter Services Training and Development Centre to investigate what would be required for Combined Operations. From this emerged the requirements for landing craft up to the size of the LCI/LCT. After June 1940 the RN realised that the smaller craft would require carried to the landing areas if an invasion of Europe was required.

The first step was the Landing Ship Infantry - Large (the equivalent of the US APA). The first 3 were converted in the second half of 1940, being Glenearn, Glengyle and Glenroy with 12 LCA and 2 LCM(1) to land the infantry these ships carried. They were improved as the war went on, eventually carrying 24 LCA and 3 LCM. Other LSI followed in Large, Medium and Small sizes, the latter being converted from cross Channel ferries of the time. Other LSI were converted as required for specific operations from large cargo liners used as troopships or ferries, with lifeboats replaced by small landing craft.

The 2 LSS referred to above were also converted from mid-1940 to carry 13 LCM(1) of a design created by the ISTDC. The LCM(1) was capable of carrying a 20 ton tank initially and landing more kit than the LSI could hope to achieve quickly. They were not used operationally due to their short range but were useful ferrying landing craft between ports or recovering damaged craft from Normandy. By Aug 1944, they were converted again with massive stern gantries to allow the shipment of rolling stock to Europe.

These vessels were followed by 3 Landing Ship Gantry conversions from RFA tankers - Dewdale, Derwentdale and Ennerdale - in 1941, able to carry 14/15 LCM(1) which were carried on deck and put into the water over the ships's side via the gantries.
http://www.rfanostalgia.org/gallery3/RF ... ST/Dewdale

Britain also used 2 heavy lift cargo ships as Landing Ship Carrier from 1942, able to carry 21 LCM(1). Then came the LSD able to carry up to 36 loaded LCM(3) or 2 or 3 loaded LCT (depending on type).

The LSS, LSG & LSC were simply a means of transporting landing craft to an invasion area to be loaded from other ships. The LSD could carry pre-loaded landing craft ready to take part in the assault.

Post-war the lines between the APA/LSI on the one hand and the LSD on the other begin to blur around 1960 as the US created the LPD (Amphibious Transport Dock), a ship combining the troop carrying features with the dry dock as in today's San Antonio class above. Britain's Fearless and Intrepid followed a similar route. That concept was then merged in the 1970s into the helicopter carrier to produce the LHA/LHD of the Tarawa and Wasp classes able to carry troops and land them either by air or by sea.

And then of course we have the LST able to carry tanks and vehicles on oceanic journeys and land them directly on the beach. That starts for the RN with the 3 Maracaibo tanker conversions in 1941 followed by 3 purpose designed LST(1) Boxer class, which ultimately proved too large for the task. The USN LST(2) was mass produced for the purpose and was hugely successful. As supplies of the LST(2) to the RN were expected to be limited after late-1943, the RN undertook its own design using steam power with which the building yards were familiar. This became the LST(3) and entered service in 1945. The LST(2) & (3) were also able to carry smaller landing carft like LCA, LCM or LCT.

daveshoup2MD
Member
Posts: 1541
Joined: 01 Feb 2020 18:10
Location: Coral and brass

Re: IJA Landing Operation Ships with slopes at the stern

Post by daveshoup2MD » 30 Jan 2022 17:24

EwenS wrote:
30 Jan 2022 14:04
Throughout the inter-war period Britain experimented with a number of small landing craft types. This culminated in 1938 with setting up of the Inter Services Training and Development Centre to investigate what would be required for Combined Operations. From this emerged the requirements for landing craft up to the size of the LCI/LCT. After June 1940 the RN realised that the smaller craft would require carried to the landing areas if an invasion of Europe was required.

The first step was the Landing Ship Infantry - Large (the equivalent of the US APA). The first 3 were converted in the second half of 1940, being Glenearn, Glengyle and Glenroy with 12 LCA and 2 LCM(1) to land the infantry these ships carried. They were improved as the war went on, eventually carrying 24 LCA and 3 LCM. Other LSI followed in Large, Medium and Small sizes, the latter being converted from cross Channel ferries of the time. Other LSI were converted as required for specific operations from large cargo liners used as troopships or ferries, with lifeboats replaced by small landing craft.

The 2 LSS referred to above were also converted from mid-1940 to carry 13 LCM(1) of a design created by the ISTDC. The LCM(1) was capable of carrying a 20 ton tank initially and landing more kit than the LSI could hope to achieve quickly. They were not used operationally due to their short range but were useful ferrying landing craft between ports or recovering damaged craft from Normandy. By Aug 1944, they were converted again with massive stern gantries to allow the shipment of rolling stock to Europe.

These vessels were followed by 3 Landing Ship Gantry conversions from RFA tankers - Dewdale, Derwentdale and Ennerdale - in 1941, able to carry 14/15 LCM(1) which were carried on deck and put into the water over the ships's side via the gantries.
http://www.rfanostalgia.org/gallery3/RF ... ST/Dewdale

Britain also used 2 heavy lift cargo ships as Landing Ship Carrier from 1942, able to carry 21 LCM(1). Then came the LSD able to carry up to 36 loaded LCM(3) or 2 or 3 loaded LCT (depending on type).

The LSS, LSG & LSC were simply a means of transporting landing craft to an invasion area to be loaded from other ships. The LSD could carry pre-loaded landing craft ready to take part in the assault.

Post-war the lines between the APA/LSI on the one hand and the LSD on the other begin to blur around 1960 as the US created the LPD (Amphibious Transport Dock), a ship combining the troop carrying features with the dry dock as in today's San Antonio class above. Britain's Fearless and Intrepid followed a similar route. That concept was then merged in the 1970s into the helicopter carrier to produce the LHA/LHD of the Tarawa and Wasp classes able to carry troops and land them either by air or by sea.

And then of course we have the LST able to carry tanks and vehicles on oceanic journeys and land them directly on the beach. That starts for the RN with the 3 Maracaibo tanker conversions in 1941 followed by 3 purpose designed LST(1) Boxer class, which ultimately proved too large for the task. The USN LST(2) was mass produced for the purpose and was hugely successful. As supplies of the LST(2) to the RN were expected to be limited after late-1943, the RN undertook its own design using steam power with which the building yards were familiar. This became the LST(3) and entered service in 1945. The LST(2) & (3) were also able to carry smaller landing carft like LCA, LCM or LCT.
Nice summary. A couple of minor points: USS Henderson, nicely illustrated by Fontessa above, was designed before WW I as what amounted to an attack transport (APA/LSI-ype) very consciously, as an element of the expected US strategy in the event of a Pacific War with Japan - as such, she was designed to carry landing craft, along with what amounted to a reinforced battalion landing team. As such, she may be the first such ship designed and built as such for any navy.

However, because of WW I, she was used as a point to point trooper during the war and for much of the interwar period; she did serve as a dedicated "self unloader" for some of the interwar fleet exercises, but that was not her full-time role, and is why she was (generally) equipped with ships boats, etc. in the 1930s. In WW II, she was used as a pint to point trooper before being converted to a hospital ship. Also, and this is a minor point, although some USN APA/AKA types did use the "climb down the cargo net" technique, others were built with heavy duty davits/gantries that allowed the troops to board landing craft before they were loaded.

One other minor point on train ferries - the USN converted three fairly large, ocean-going ships during WW II to serve as mother ships for landing craft along the lines of the RN "heavy lift" ships mentioned above; because of the flood of specialized designs, they spent most of their service as aircraft ferries and the like, rather than assault ships. One other minor variation on the "mother ship" concept were the USN CM and AN designs converted to carry LVTS, and used as assault ships in the Pacific.

The other points are that the flooded well deck that has become the standard for such shipping today has a couple of antecedents, including British designs in the 'teens for what we'd call a "flo-flo" ship today, and the various designs for heavy lift ships in the interwar era - the Norwegians were well known for barge carriers, for example. Finally, in terms of self-propelled shallow draft landing craft, complete with ramps, the British X-lighters and the like designed because of the Dardanelles probably were the first, although specialized "surf boats" (unpowered, but built for the purpose with shallow draft, not simply standard ships boats) date to (at least) the Nineteenth Century.

Shinshu Maru is an impressive design, but it seems there was a fair amount similar thinking by the three navies in the interwar period.

User avatar
fontessa
Member
Posts: 4511
Joined: 25 Mar 2011 16:29
Location: Yokohama, Japan

Re: IJA Landing Operation Ships with slopes at the stern

Post by fontessa » 30 Jan 2022 20:39

Hello tom,
tom! wrote:
30 Jan 2022 12:27
Didn´t the other IJA landing craft carriers (Ko-, Otsu-, Hei-Type) also had this stern ramp mechanism?

tom! ;)
Since 神洲丸 Shishu Maru was highly evaluated, it was decided in 1939 to build the below "Special Transport Ships" similar to her.
FIG1 shows the Concept. Shinshu Maru had a peculiar appearance and caught the attention of the United States, so they made the basic form look like an unobtrusive merchant ship. And it also had slopes so that she could be a landing operation ship. FIG2 shows M-Hei Type basic figure. We can see the large Daihatsu storage area and the stern doors. The large Daihatsu storage area will be a hangar when completed as an aircraft carrier. 熊野丸 Kumano Maru was completed as an aircraft carrier. As shown in FIG3, she was equipped with an elevator, arresting wires, and a landing leading lights system. And she had the left alopes and rear doors.

丙型 “Hei” Type C
あきつ丸 Akitsu Maru (10,000t class) / Completed on January 1942
にぎつ丸 Nigitsu Maru (10,000t class) / Completed on March 1943
M甲型 “M-Ko” M-Type A
日向丸 Hyuga Maru (10,000t class) / Completed on November 1944
吉備津丸 Kibitsu Maru (10,000t class) / Completed on December 1943
摂津丸 Setsu Maru (10,000t class)/ Completed on January1945
甲型 “Ko” Type A
摩耶山丸 Mayayama Maru (10,000t class) / Completed onDecember1942
玉津丸 Tamatsu Maru (5,000t class) / Completed on January 1944
高津丸 Takatsu Maru (5,000t class) / Completed on January 1944
M丙型 “M-Hei” M-TyepC
熊野丸 Kumano Maru (10,000t class) / Completed on March 1945
ときつ丸 Tokitsu Maru (10,000t class) / Not Completed


上陸作戦艦艇 概念.jpg

上陸 M丙型配置図.jpg

上陸 熊野丸.jpg


fontessa
You do not have the required permissions to view the files attached to this post.

Fatboy Coxy
Member
Posts: 898
Joined: 26 Jul 2009 16:14
Location: Essex, UK

Re: IJA Landing Operation Ships with slopes at the stern

Post by Fatboy Coxy » 30 Jan 2022 20:57

This is excellent fontessa, so pleased to read about it
Regards
Fatboy Coxy

Currently writing https://www.alternatehistory.com/forum/ ... if.521982/

User avatar
fontessa
Member
Posts: 4511
Joined: 25 Mar 2011 16:29
Location: Yokohama, Japan

Re: IJA Landing Operation Ships with slopes at the stern

Post by fontessa » 30 Jan 2022 21:10

Hello daveshoup2MD,
daveshoup2MD wrote:
30 Jan 2022 17:24
others were built with heavy duty davits/gantries that allowed the troops to board landing craft before they were loaded.
You mean the below? Some gantries too?
Very interesting.

上陸 APA-55 APA-56.jpg

fontessa
You do not have the required permissions to view the files attached to this post.

daveshoup2MD
Member
Posts: 1541
Joined: 01 Feb 2020 18:10
Location: Coral and brass

Re: IJA Landing Operation Ships with slopes at the stern

Post by daveshoup2MD » 30 Jan 2022 23:55

USN APAs and AKAs varied in troop capacity and unloading capabilities (a few were built for the purposes, others were converted merchantmen, others were standardized merchant hulls, etc.) so there was a wide variety, but US doctrine was - when a given ship's davits/cranes, assigned landing craft, and ship design allowed to do so - to load landing craft with troops (or cargo, or vehicles, if possible, which was rare) before they were hoisted out (or left the well deck of an LSD, of course) and went into the water. The heavy duty davits, generally known as Welin or triple-banked davits, could carry three landing craft, two stowed atop one another under the davit trackway and the third swung outboard from the davit arms. There was a quadruple bank that came along later in the war, as well.

Because no ship could carry enough boats to land all her embarked troops, after the first echelon (of troops) headed for the shore, the second echelon had to be loaded into troops already in the water, which is where the nets (generally) came in (obviously, it would have cost even more time to have a boat come alongside, hitch up, and be lifted up by the davits to a point where troops could board, then be lowered again.) Some of the initial conversions, where the heavy duty davits were not installed before operations commenced, had to rely on their boat davits, and so while small landing craft could be stowed and hoisted out, doing so with them fully loaded would have been dicey, at best, if not impossible.

It's also worth keeping in mind that the USN amphibious doctrine began with ship-to-shore operations at oceanic distances; it began with planning for war in the Pacific, after all, so the ships had to be large, with naval crews, habitability had to been reasonable, landing craft could not be regarded as expendable, etc. That came in handy for TORCH, of course, but the shore-to-shore operations that began with HUSKY allowed for much simpler techniques, and types of ships.
Last edited by daveshoup2MD on 31 Jan 2022 22:47, edited 1 time in total.

User avatar
tom!
Member
Posts: 888
Joined: 15 Dec 2003 11:42
Location: Dorsten Germany

Re: IJA Landing Operation Ships with slopes at the stern

Post by tom! » 31 Jan 2022 15:33

Hi.

Maybe a little bit off-topic but the smaller IJN No.1 Class Landing Ships had a similar mechanism for various loads on the stern as well.

jap T1 class landungsschiff T9 1944.jpg
Yours

tom! ;)
You do not have the required permissions to view the files attached to this post.

User avatar
fontessa
Member
Posts: 4511
Joined: 25 Mar 2011 16:29
Location: Yokohama, Japan

Re: IJA Landing Operation Ships with slopes at the stern

Post by fontessa » 31 Jan 2022 18:37

Thanks tpm.

She could carry Daihatsu x 4 or Kaiten X 6.

There were other slopes - patrol boats had. "Slopes" were the specialty of Japan.
They were reminiscent of the old-fashioned Momi-class destroyers. At the end of the war, the slopes were removed and replaced with depth charge projectors to escort the convoy, so there are no photos with the slopes left - I think.
PB-32 and PB-33 were used in Wake Island landing operations in 1942.

第1号 第31号型 哨戒艇.jpg

fontessa
You do not have the required permissions to view the files attached to this post.

User avatar
fontessa
Member
Posts: 4511
Joined: 25 Mar 2011 16:29
Location: Yokohama, Japan

Re: IJA Landing Operation Ships with slopes at the stern

Post by fontessa » 02 Feb 2022 09:29

EwenS wrote:
30 Jan 2022 14:04
Throughout the inter-war period Britain experimented with a number of small landing craft types. This culminated in 1938 with setting up of the Inter Services Training and Development Centre to investigate what would be required for Combined Operations. From this emerged the requirements for landing craft up to the size of the LCI/LCT. After June 1940 the RN realised that the smaller craft would require carried to the landing areas if an invasion of Europe was required.

The first step was the Landing Ship Infantry - Large (the equivalent of the US APA). The first 3 were converted in the second half of 1940, being Glenearn, Glengyle and Glenroy with 12 LCA and 2 LCM(1) to land the infantry these ships carried. They were improved as the war went on, eventually carrying 24 LCA and 3 LCM. Other LSI followed in Large, Medium and Small sizes, the latter being converted from cross Channel ferries of the time. Other LSI were converted as required for specific operations from large cargo liners used as troopships or ferries, with lifeboats replaced by small landing craft.

The 2 LSS referred to above were also converted from mid-1940 to carry 13 LCM(1) of a design created by the ISTDC. The LCM(1) was capable of carrying a 20 ton tank initially and landing more kit than the LSI could hope to achieve quickly. They were not used operationally due to their short range but were useful ferrying landing craft between ports or recovering damaged craft from Normandy. By Aug 1944, they were converted again with massive stern gantries to allow the shipment of rolling stock to Europe.

These vessels were followed by 3 Landing Ship Gantry conversions from RFA tankers - Dewdale, Derwentdale and Ennerdale - in 1941, able to carry 14/15 LCM(1) which were carried on deck and put into the water over the ships's side via the gantries.
http://www.rfanostalgia.org/gallery3/RF ... ST/Dewdale

Britain also used 2 heavy lift cargo ships as Landing Ship Carrier from 1942, able to carry 21 LCM(1). Then came the LSD able to carry up to 36 loaded LCM(3) or 2 or 3 loaded LCT (depending on type).

The LSS, LSG & LSC were simply a means of transporting landing craft to an invasion area to be loaded from other ships. The LSD could carry pre-loaded landing craft ready to take part in the assault.

Post-war the lines between the APA/LSI on the one hand and the LSD on the other begin to blur around 1960 as the US created the LPD (Amphibious Transport Dock), a ship combining the troop carrying features with the dry dock as in today's San Antonio class above. Britain's Fearless and Intrepid followed a similar route. That concept was then merged in the 1970s into the helicopter carrier to produce the LHA/LHD of the Tarawa and Wasp classes able to carry troops and land them either by air or by sea.

And then of course we have the LST able to carry tanks and vehicles on oceanic journeys and land them directly on the beach. That starts for the RN with the 3 Maracaibo tanker conversions in 1941 followed by 3 purpose designed LST(1) Boxer class, which ultimately proved too large for the task. The USN LST(2) was mass produced for the purpose and was hugely successful. As supplies of the LST(2) to the RN were expected to be limited after late-1943, the RN undertook its own design using steam power with which the building yards were familiar. This became the LST(3) and entered service in 1945. The LST(2) & (3) were also able to carry smaller landing carft like LCA, LCM or LCT.
daveshoup2MD wrote:
30 Jan 2022 17:24
EwenS wrote:
30 Jan 2022 14:04
Throughout the inter-war period Britain experimented with a number of small landing craft types. This culminated in 1938 with setting up of the Inter Services Training and Development Centre to investigate what would be required for Combined Operations. From this emerged the requirements for landing craft up to the size of the LCI/LCT. After June 1940 the RN realised that the smaller craft would require carried to the landing areas if an invasion of Europe was required.

The first step was the Landing Ship Infantry - Large (the equivalent of the US APA). The first 3 were converted in the second half of 1940, being Glenearn, Glengyle and Glenroy with 12 LCA and 2 LCM(1) to land the infantry these ships carried. They were improved as the war went on, eventually carrying 24 LCA and 3 LCM. Other LSI followed in Large, Medium and Small sizes, the latter being converted from cross Channel ferries of the time. Other LSI were converted as required for specific operations from large cargo liners used as troopships or ferries, with lifeboats replaced by small landing craft.

The 2 LSS referred to above were also converted from mid-1940 to carry 13 LCM(1) of a design created by the ISTDC. The LCM(1) was capable of carrying a 20 ton tank initially and landing more kit than the LSI could hope to achieve quickly. They were not used operationally due to their short range but were useful ferrying landing craft between ports or recovering damaged craft from Normandy. By Aug 1944, they were converted again with massive stern gantries to allow the shipment of rolling stock to Europe.

These vessels were followed by 3 Landing Ship Gantry conversions from RFA tankers - Dewdale, Derwentdale and Ennerdale - in 1941, able to carry 14/15 LCM(1) which were carried on deck and put into the water over the ships's side via the gantries.
http://www.rfanostalgia.org/gallery3/RF ... ST/Dewdale

Britain also used 2 heavy lift cargo ships as Landing Ship Carrier from 1942, able to carry 21 LCM(1). Then came the LSD able to carry up to 36 loaded LCM(3) or 2 or 3 loaded LCT (depending on type).

The LSS, LSG & LSC were simply a means of transporting landing craft to an invasion area to be loaded from other ships. The LSD could carry pre-loaded landing craft ready to take part in the assault.

Post-war the lines between the APA/LSI on the one hand and the LSD on the other begin to blur around 1960 as the US created the LPD (Amphibious Transport Dock), a ship combining the troop carrying features with the dry dock as in today's San Antonio class above. Britain's Fearless and Intrepid followed a similar route. That concept was then merged in the 1970s into the helicopter carrier to produce the LHA/LHD of the Tarawa and Wasp classes able to carry troops and land them either by air or by sea.

And then of course we have the LST able to carry tanks and vehicles on oceanic journeys and land them directly on the beach. That starts for the RN with the 3 Maracaibo tanker conversions in 1941 followed by 3 purpose designed LST(1) Boxer class, which ultimately proved too large for the task. The USN LST(2) was mass produced for the purpose and was hugely successful. As supplies of the LST(2) to the RN were expected to be limited after late-1943, the RN undertook its own design using steam power with which the building yards were familiar. This became the LST(3) and entered service in 1945. The LST(2) & (3) were also able to carry smaller landing carft like LCA, LCM or LCT.
Nice summary. A couple of minor points: USS Henderson, nicely illustrated by Fontessa above, was designed before WW I as what amounted to an attack transport (APA/LSI-ype) very consciously, as an element of the expected US strategy in the event of a Pacific War with Japan - as such, she was designed to carry landing craft, along with what amounted to a reinforced battalion landing team. As such, she may be the first such ship designed and built as such for any navy.

However, because of WW I, she was used as a point to point trooper during the war and for much of the interwar period; she did serve as a dedicated "self unloader" for some of the interwar fleet exercises, but that was not her full-time role, and is why she was (generally) equipped with ships boats, etc. in the 1930s. In WW II, she was used as a pint to point trooper before being converted to a hospital ship. Also, and this is a minor point, although some USN APA/AKA types did use the "climb down the cargo net" technique, others were built with heavy duty davits/gantries that allowed the troops to board landing craft before they were loaded.

One other minor point on train ferries - the USN converted three fairly large, ocean-going ships during WW II to serve as mother ships for landing craft along the lines of the RN "heavy lift" ships mentioned above; because of the flood of specialized designs, they spent most of their service as aircraft ferries and the like, rather than assault ships. One other minor variation on the "mother ship" concept were the USN CM and AN designs converted to carry LVTS, and used as assault ships in the Pacific.

The other points are that the flooded well deck that has become the standard for such shipping today has a couple of antecedents, including British designs in the 'teens for what we'd call a "flo-flo" ship today, and the various designs for heavy lift ships in the interwar era - the Norwegians were well known for barge carriers, for example. Finally, in terms of self-propelled shallow draft landing craft, complete with ramps, the British X-lighters and the like designed because of the Dardanelles probably were the first, although specialized "surf boats" (unpowered, but built for the purpose with shallow draft, not simply standard ships boats) date to (at least) the Nineteenth Century.

Shinshu Maru is an impressive design, but it seems there was a fair amount similar thinking by the three navies in the interwar period.
Thanks for the comments. Your comments are helpful as my knowledge of the Royal Navy is limited. I would be grateful if you could answer the following questions.
(1) What was the background of the Royal Navy's remodeling of train ferries to landing craft transport ships - Princess Iris and Daffodil?
(2) Why weren't the stern slopes finally adopted?
(3) About the picture below. This is a post-war photo, but it can be read as if the landing craft was being lowered with the soldiers on board in the caption. Is this interpretation correct? If so, was it done even during WWII?


上陸 HRS Rocksand (F184).jpg

fontessa
You do not have the required permissions to view the files attached to this post.

EwenS
Member
Posts: 457
Joined: 04 May 2020 11:37
Location: Scotland

Re: IJA Landing Operation Ships with slopes at the stern

Post by EwenS » 02 Feb 2022 17:03

Fontessa,
I’m not sure I can fully answer your queries but I do have some more background information that might help.

In 1939 there were only 2 train ferry routes between Britain and Europe each with 3 ships.

The Dover to Dunkirk route used Hampton Ferry, Shepperton Ferry and Twickenham Ferry built 1934/35. The first pair were requisitioned as minelayers, then used as transports for equipment to France for the BEF before being sent to the Stranraer, Scotland to Northern Ireland service as roll on roll off general transports. In 1944/45 they were again used to move rolling stock to France.

The other route was Harwich to Zeebrugge using Train Ferry No.1 (later HMS Iris, later HMS Princess Iris), No.2 (lost 1940) and No.3 (later HMS Daffodil) which had all been built in 1917. After moving the BEF to France and helping rescue it in 1939/40 the two survivors were converted to LSS.

Why only 2 of the remaining 5 as LSS? I don’t know. But the first group had an enclosed train deck rather than the largely open platform of the ships converted to LSS, which may have made then less suitable.

According to DK Brown the RN was looking for a means of transporting landing craft (principally LCM) to the scene of a landing to augment the landing craft, if any, able to be carried in other troop transport ships. In 1940 those transports might not all have been envisaged as being the LSI that came to pass. More like the cargo liners used as troopships. The landing craft were to be carried on trolleys, so no doubt the rails already installed were useful. There were 3 rows of landing craft and a powered trolley at the forward end moved LC from the outside rows to the centre row to be launched through a chute that had to be cut into the stern. So once converted a lot of deck area was lost limiting their use for other purposes. And as I noted earlier their range was limited due to their cross channel origins, so they would have been incompatible with the large Glens converted at the same time, but would have been more useful alongside the smaller cross-Channel ferry conversion LSI(S) had events not moved on.

Incidentally if you want a book with brief histories of the various Ferry ships requisitioned in WW2 for a multitude of uses then “Short Sea:Long War” by John de S. Winser published by the World Ship Society is recommended.

Putting a stern chute into the LSG tanker conversions and the LSC heavy lift conversions was impossible due to their aft machinery layout. And by then the RN was looking forward to the LSD coming from the USA, which arrived in time for D-Day.

Information about the background to the LSD probably lies in Friedman’s book on US amphibious shipping, but I don’t have a copy of that.

As for the final question and the photo about loading the LCA on the ship or in the water, I think the answer is both and depends on the ships. Unlike the US, Britain didn’t build classes of large landing ships. With the exception of the Lend Lease ships, virtually everything in the RN was a conversion of an existing vessel.

For the RN we have the 3 Glens, 13 Lend Lease C1-S-AY1 (see photo of Rocksand) plus Persimmon, Lamont plus Keren & Karanja and the 3 Australian vessels which were all fully fledged LSI(L). Most of them had power operated davits to lower the landing craft so I can see their first load of troops being loaded on the ship with follow up loaded over the side. This was certainly true of the US built Empire Arquebus on D-Day. However as I noted many other LSI were simply cargo liners taken up for specific operations with LC in place of lifeboats. In those cases the LC would be hand lowered so probably loaded on the water.

Britain did have a group of LSI(H), the H being for “hand hoisting” referring to the means of raising/lowering the landing craft. These were again conversions from, or temporary take ups from, former cross Channel / Irish Sea ferries. Given the difference in weight of a loaded and unloaded LCA with up to 36 troops aboard, and the high freeboard of many of these ships I think it likely they loaded the troops over the side.

The LSI(H) Princess Maud on D-Day discharged US troops into LCM alongside but discharged loaded LCA from her davits, with one being damaged in the process.
https://www.combinedops.com/Combined-Op ... in-WW2.htm


The Combined Operations website is worth a look for more information.
https://www.combinedops.com/Combined-Op ... -pages.htm

Although the photo of Rocksand is postwar, it is only just post war. The last RN planned amphibious Operation was Operation Zipper for which the troops were loading as the war ended on 15 Aug. It went ahead unopposed on 9 Sept 1945 as the quickest means of getting boots on the ground in Malaya. Rocksand was involved in that operation.

Incidentally, in 1982 troops were transferred from SS Uganda and QE2 to landing craft via the side doors in these ships normally used for loading passengers.

daveshoup2MD
Member
Posts: 1541
Joined: 01 Feb 2020 18:10
Location: Coral and brass

Re: IJA Landing Operation Ships with slopes at the stern

Post by daveshoup2MD » 02 Feb 2022 22:21

fontessa wrote:
02 Feb 2022 09:29
questions
Sure. Ewen covered a lot of it, but as far as the LSD design and its antecedents goes, Friedman's "US Amphibious Ships and Craft" spends about 20 pages going into the various ideas and cross-pollination between the UK and US designers that led to both the LST and LSD; these include the British types that Ewen mentions above, as well as the flo-flo well-decks concept, and the British concepts that led to the LST, and US concepts that mirrored them - as an example, the US did look at designs with "stern slipways" (not well decks) for launching landing craft over the stern as early as February, 1941.

The USN also looked at "landing force tenders" based on the Seatrain designs also mentioned above, that basically would have off-loaded landing craft over the side, via cut-down segment of the hull, and kicked around a program of 50 such new-build vessels in 1941. The USMC asked for a "tank carrier" that could carry 36 medium tanks, 18 of them loaded aboard smaller landing that itself could be launched by the mother ship, about the same time, which would have been a Seatrain/LST hybrid, sort of...

Tthe final concept of what became the LSD gelled under Capt. T.A. Hussey, RN, who pushed for it and got a basic design together in late 1941; that was passed to the US, and after additional discussion and refinements by BuShips and contract naval architects (basically the same process as the USN LST design), was accepted - the first orders for US LSTs came in December, 1941, with the first keel laid in June, 1942, and completion in October. The LSD orders followed in January, 1942, with first keels laid in June and completions in June, 1943.

One minor sidelight on the US-built LSI/APAs for the RN, like HMS Rocksand; these were based on US standard "C1" freighter/passenger cargo hulls, largely because of a need for attack transports for OVERLORD/NEPTUNE; because they were - essentially - "cross channel" ships, the troop accommodations could be very austere, and the 13 Empire Weapon class ships were so - they were built in the US and converted, for the most part, in the UK. They were useful enough in "short sea" type operations, but when the RN deployed some of them to the Pacific, the shortcomings of the design, in comparison to the bigger USN APAs (based on the standard C2 and C3 hulls, or prewar passenger/cargo ships), became apparent.

Return to “Japan at War 1895-1945”