Slitherine

quote:

ORIGINAL: JWE

quote:

ORIGINAL: Gary Childress
I was operating on the assumption that the ships could be reconstructed using other facilities than the construction slips.

Ok, don’t want to get too deep into this, but here’s a quickie on ship construction/conversion.

Ships can be built in a dry slipway or a wet slip or a wet dock. In a dry slip, can be oriented two ways, lateral launch or longitudinal launch, depends on shipyard terrain. If a dry slip (pics 1, 2, and 5), it is built, primarily to main deck level (see Missouri, pic 5), with darn little superstructure, no guns, no fittings, i.e., as little weight as possible to avoid damage during launch (or to avoid it being so heavy it doesn’t move at all).

Pic 3 is Mount Vernon in what I call a graving dock (shallow with little in the way of heavy equipment – good for hull work). Ships can be constructed in wet slips like this. One may complete more of a ship constructed in this manner, prior to launch, but as one can see, they might be draft limited so, again, launch weight becomes a factor, depending on the depth of the slip.

Pic 4 is Texas in a full-boogie drydock (deep, wide, stuff for heavy lifting). A modern one, yes, but one gets the idea. Ships can be constructed in wet slips like this (a construction drydock) in which case they can complete through topsides prior to launch. The Yamato-type construction ways looked like a cross between pics 3 and 4, with construction girders like pic 5 (good also for hanging tarps to hide the things).

If built in a dry slip, a ship “may” be moved to a graving-type fitting dock, and/or a fitting drydock (maybe one, maybe the other, maybe both, maybe neither – depends). Then ship goes to a fitting pier like in pic 6. Fitting pier (or fitting dock) has heavy lifting gear alongside, and might be one sided (port side to, in pic 6) or two sided. So one must have a sufficient sized (and facilitated) construction slip, and a sufficient sized (and facilitated) graving and/or drydock, and a sufficient sized (and facilitated) fitting dock/pier/slip/whatever.

Conversions don’t require construction dry slips, but do require some time in a graving/dry dock. If the drydock is also a construction dock one is borked. If the drydock is also a fitting drydock (almost always the case), one is equally borked. Conversions next require substantial time at the fitting dock/pier/slip. Depending on how many (or few) of these there are, and of what size and facility scale, one may well be equally borked.

As one may imagine, full-boogie capital-ship construction drydocks were a horridly inefficient use of resources in the ‘30s and ‘40s. They were populated for years by each ship, during which time they were unavailable for fitting or hull upgrades (bulges, armor/girder mod, reboilering/reproping) and wartime damage repair, to other ships of consequent size. One must have yet another large drydock with yet more duplicate facilities, and yet another fitting pier with yet more duplicate facilities.

It’s not rocket science, but ship construction planning is a professional endeavor because of things like this. Every ship class is different, every yard is different, every constructor (the one who makes it happen) is different. But that’s construction/conversion in a nutshell; the actuality (in the 30s and 40s) was much more complex, particularly for Japan.

quote:

ORIGINAL: Shark7
Given the types of docks here, and given that you need a suitable site for such a dock (it seems a natural harbor would be a natural location for a ship-building endeavour)....Did Japan have any expansion room to help boost their ship-building programme (barring any logistical considerations)?

What I'm asking is did Japan have any additional suitable locations to allow for construction of large ship-building slips and docks? And if so, how involved would the building of a new slip/dock be?

quote:

ORIGINAL: JWE

quote:

ORIGINAL: Shark7
Given the types of docks here, and given that you need a suitable site for such a dock (it seems a natural harbor would be a natural location for a ship-building endeavour)....Did Japan have any expansion room to help boost their ship-building programme (barring any logistical considerations)?

What I'm asking is did Japan have any additional suitable locations to allow for construction of large ship-building slips and docks? And if so, how involved would the building of a new slip/dock be?

That’s a good question and a really hard one. The best answer is no, not in any practical sense. To have a capital yard, you need three things: a suitable terrain footprint, a population (and desirably an industrial) center right next door, and a transportation infrastructure to move materials (steel, and systems, and bears, oh my) to the yard.

Look at the Yamato pic. That’s the majority of Japan’s coastline; mountains down to the beach. Good in one sense because there’s deep water up to the beach (one requirement), but bad in that there’s very little flat land in contact with the shore (another requirement, and one reason why some places built and launched laterally). Where there was some flat land (Tokyo, Osaka, etc …) it was already built up and one would have to purchase and demo city parts to expand. Many of the city parts were already industrialized so one might have to demo a factory to expand a yard. Big bucks.

It was done during the war, and in more than one location, but total floorplan increases, for the few that did, were on the order of 20% - not much. One could expand outward by dredging, but then an advantage (deep water) becomes a liability and bites you in the tush. Also big bucks. So not a lot of room for expansion, for lots of different reasons.

New yards were even harder. There may well have been places with suitable terrain footprints, but nothing in the vicinity of a population center, and no place to put a population center (otherwise there would already be one). Yokosuka NSY employed 40,000 people. Transportation infrastructure was nonexistent to out-of-the-way places; recall the stories of moving prototype airplanes from the factory to the test field by ox-cart over dirt roads. Japan built several small new yards in places like that, but they were real dinky and set up on an emergency basis; barracks for a few hundred (maybe up to 1,000) workers, and supplied by sea. They did trawler type auxiliaries, woodies, and some std-D & E merchies – 30 to 50m stuff.

Not just my opinion, Mark Parillo describes all these things, as do Evans & Peattie. They might be even more categorical.

quote:

ORIGINAL: Shark7
So the answer is no...other than expanding the existing facilities to the strained limit...which in itself caused additional problems.

The only thing I see as feasibly possible by your description is a very small new yard or two, complete with rail/industrial expansion required, to build Kaibokan type vessels...and even that would be an expensive endeavor or a pure logistical nightmare. Not worth the expense pre-war unless you were certain you would need the capacity, which the powers that be did not plan for.

quote:

ORIGINAL: JWE

quote:

ORIGINAL: Gary Childress
I was operating on the assumption that the ships could be reconstructed using other facilities than the construction slips.

Ok, don’t want to get too deep into this, but here’s a quickie on ship construction/conversion.

Ships can be built in a dry slipway or a wet slip or a wet dock. In a dry slip, can be oriented two ways, lateral launch or longitudinal launch, depends on shipyard terrain. If a dry slip (pics 1, 2, and 5), it is built, primarily to main deck level (see Missouri, pic 5), with darn little superstructure, no guns, no fittings, i.e., as little weight as possible to avoid damage during launch (or to avoid it being so heavy it doesn’t move at all).

Pic 3 is Mount Vernon in what I call a graving dock (shallow with little in the way of heavy equipment – good for hull work). Ships can be constructed in wet slips like this. One may complete more of a ship constructed in this manner, prior to launch, but as one can see, they might be draft limited so, again, launch weight becomes a factor, depending on the depth of the slip.

Pic 4 is Texas in a full-boogie drydock (deep, wide, stuff for heavy lifting). A modern one, yes, but one gets the idea. Ships can be constructed in wet slips like this (a construction drydock) in which case they can complete through topsides prior to launch. The Yamato-type construction ways looked like a cross between pics 3 and 4, with construction girders like pic 5 (good also for hanging tarps to hide the things).

If built in a dry slip, a ship “may” be moved to a graving-type fitting dock, and/or a fitting drydock (maybe one, maybe the other, maybe both, maybe neither – depends). Then ship goes to a fitting pier like in pic 6. Fitting pier (or fitting dock) has heavy lifting gear alongside, and might be one sided (port side to, in pic 6) or two sided. So one must have a sufficient sized (and facilitated) construction slip, and a sufficient sized (and facilitated) graving and/or drydock, and a sufficient sized (and facilitated) fitting dock/pier/slip/whatever.

Conversions don’t require construction dry slips, but do require some time in a graving/dry dock. If the drydock is also a construction dock one is borked. If the drydock is also a fitting drydock (almost always the case), one is equally borked. Conversions next require substantial time at the fitting dock/pier/slip. Depending on how many (or few) of these there are, and of what size and facility scale, one may well be equally borked.

As one may imagine, full-boogie capital-ship construction drydocks were a horridly inefficient use of resources in the ‘30s and ‘40s. They were populated for years by each ship, during which time they were unavailable for fitting or hull upgrades (bulges, armor/girder mod, reboilering/reproping) and wartime damage repair, to other ships of consequent size. One must have yet another large drydock with yet more duplicate facilities, and yet another fitting pier with yet more duplicate facilities.

It’s not rocket science, but ship construction planning is a professional endeavor because of things like this. Every ship class is different, every yard is different, every constructor (the one who makes it happen) is different. But that’s construction/conversion in a nutshell; the actuality (in the 30s and 40s) was much more complex, particularly for Japan.

quote:

ORIGINAL: JWE

Thought you might like a list of construction yards that provided ships to the IJN during the war period. No warranty about the pre-war period. Only the NSYs and civilian yards in bold built warships from DDs on up (assumes Matsu was a DD). The rest built the little things (Es, SCs, auxPBs, etc ..). Civilian yards also had to build large numbers of replacement cargo and tanker vessels.

Naval Shipyards
Kure Naval Yard: Kure: Ways - 1 @ 300m, 1 @ 225m, [1 @ 175m, 2 @ 150m]; alt 5 @ 125m, longitudinal construction.
Yokosuka Naval Yard: Yokosuka : Ways – 1 @ 300m, 1 @ 200m, 2 @ 175m, 2 @ 150m.
Sasebo Naval Yard: Sasebo: Ways – 1 @ 200m, 1 @ 175m, 3 @ 150m.
Maizuru Naval Yard: Maizuru: Ways – 1 @ 150m, 4 @ 125m.

Civilian Shipyards
Mitsubishi Heavy Industries: Nagasaki: Ways - 1 @ 275*m, 1 @ 225m, 2 @ 150m, 4 @ 125m.
Mitsubishi Heavy Industries: Kobe: Ways - 1 @ 150m, 2 @ 125m, 3 @ 100m.
Mitsubishi Heavy Industries: Yokohama: Ways - 1 @ 200m, 1 @ 150m, 2 @ 100m.
Mitsubishi Heavy Industries: Shimonoseki: Ways - 1 @ 150m, 2 @ 100m

Kawasaki Shipbuilding: Kobe: Ways - 1 @ 250m, 2 @ 150m, 3 @ 100m.
Kawasaki Shipbuilding: Tanagawa: Ways - 3 @ 100m
Kawasaki Shipbuilding: Senshu: Ways - 3 @ 125m

Hitachi Shipbuilding: Sakurajima: Ways – 2 @ 125m
Hitachi Shipbuilding: Mukojima: Ways – 2 @ 100m.
Hitachi Shipbuilding: Innoshima: Ways – 1 @ 100m, 2 @ 75m.
Hitachi Shipbuilding: Hikoshima: Ways – 1 @ 100m, 2 @ 75m.

Kawaminami HI: Koyagi: Ways – 1 @ 125m. 1 @ 100m, 2 @ 75m
Kawaminami HI: Urasaki: Ways – 1 @ 125m. 1 @ 100m.

Uraga Dockyards: Uraga/Tokyo: Ways - 1 @ 150m, 2 @ 125m, 2 @ 100m.
Fujinagata Shipbuilding: Sakai/Osaka: Ways – 3 @ 125m.

Tokyo Shipbuilding: Ishikawa: Ways - 3 @ 125m.
Mitsui Shipbuilding: Tamano: Ways – 3 @ 125m.
Harima Shipbuilding: Harima: Ways – 1 @ 125m, 1 @ 100m, 1 @ 75m.
Nippon Koukan: Tsurumi: Ways – 1 @ 125m. 2 @ 75m
Osaka Shipbuilding: Osaka: Ways – 1 @ 125m, 1 @ 75m
Niigata Iron Factory: Niigata: Ways – 1 @ 125m, 2 @ 75m
Naniwa Dock: Osaka: Ways – 1 @ 100m, 1 @ 75m
Hakodate Dock: Hakodate: Ways – 1 @ 100m, 1 @ 75m