Saipan Invasion Question

[Dereck]

I know (from landing a recon force) that the following units are located on Saipan:

- Maizuru 2nd SNLF
- Saipan Base Force
- Saipan Coastal Gun Regiment
- Sasebo 7th SNLF
- Yokosuka 1st SNLF
- 3rd South Seas Detachment
- 5th Base Force
- 5th Coastal Gun Regiment
- 5th NLF
- 9th Ind Brigade
- 25th Aviation Unit
- 31st Army HQ
- 43rd Division
- 47th Ind Mixed Brigade
- 51st Construction Battalion
- 55th Naval Guard
- 65th Naval Guard
- 128th IJN Base Force
- 145th IJN Base Force

I'm going to be sending in my V Amphib Corps and some extra artillery:
- V Amphib Corps
- 1st USMC Division
- 2nd USMC Division
- 18th USA Engineer Regiment
- 1st USMC Armored Amphibious Battalion
- V USMC Corps Artillery
- 56th USA Coastal Artillery Regiment
- 14th USMC Defense Battalion

Following units in floating reserve:
- 3rd USMC Division
- 193rd USA Tank Battalion

My question is:

Should I sent in the 3rd USMC Division and 193rd USA Tank Battalion with the initial wave and have the III Corps as my reserve? The III Corps consists of the 25th, 27th and 40th USA Divisions, 144th USA FA Regiment, 251st USA Coast AA Regiment, 2nd USMC Armored Amphibious Battalion and 763rd USA Tank Battalion.

I'm sure I don't have enough landing craft to put all the III Corps in LSTs but between remaining LSTs and APs I should have the tonnage to load them and have them offshore ready to land in case I'd need them.

Thanks.

[DuckofTindalos]

I'd send in all the Marines if I were you, Dereck. Looks like you have a tough nut to crack there.

[JeffroK]

Whats on Tinian & Guam?

If its light, land your force there, build up a base then step from there to Saipan. In the mean time keep smashing Saipan with everything you have.

I would also land every Grunt you can get into a first wave, calculating roughly, you are outnumbered with the above force.

[Dereck]

Yeah I've already started to lean that way. I have enough LSTs for my V Amphib Corps but I'm going to have to put some of my III Corps (Floating Reserve) on APs because Saipan is just too far away to take the LSTs back to reload.

I've already sent 10 battleships and 6 heavy cruisers (plus escorts) along with 12 fleet and 9 light carriers to start pounding the crap out of Saipan. I'm not worried about taking the island because I know I can (thinks positive for cyber-troops' benefit) but I would really like to be able to target the coastal guns specifically. I don't want to attack the infantry units with my ships and air strikes -- I'm going to land infantry to take care of them -- but I would like to be able to take out as many surface targets as I can so they can't shoot back at me.

[DuckofTindalos]

You've just touched on one of the grievances many people have; that you can't decide precisely which ground units to attack. It would be excellent to just be able to drop iron on the CD's.

[Dereck]

ORIGINAL: Terminus

You've just touched on one of the grievances many people have; that you can't decide precisely which ground units to attack. It would be excellent to just be able to drop iron on the CD's.

I know this may not confirm to some peoples theories, but in real life the US Navy was damn good at taking out just about every target above ground they wanted and the Japanese didn't have much to fire back at them unless it was below ground.

[DuckofTindalos]

We don't disagree...

[Alikchi2]

If I was you I would be tempted to not land on Saipan at all. What a huge force!

Still, if you're going to go for it, I'd try Guam or Tinian first, as well. Pound Saipan for weeks if necessary. Especially port attacks.

[saj42]

If you use APs in first wave then only part load them so they unload in one turn ( IIRC 1000 load points max).
I'd also drop the 14th USMC Defense Battalion and replace with 2nd USMC Armored Amphibious Battalion or 763rd USA Tank Battalion.
In the last day or two of bombardments have some forces target ground units - hopefully you can disrupt a major combat unit so its artillery is not as effective firing against your landing.

You never have enough amphibious shipping[:@]

All sounds good in theory - I've yet to get to launch a major invasion - good luck to you

[pompack]

ORIGINAL: Tallyho!

If you use APs in first wave then only part load them so they unload in one turn ( IIRC 1000 load points max).
I'd also drop the 14th USMC Defense Battalion and replace with 2nd USMC Armored Amphibious Battalion or 763rd USA Tank Battalion.
In the last day or two of bombardments have some forces target ground units - hopefully you can disrupt a major combat unit so its artillery is not as effective firing against your landing.

You never have enough amphibious shipping[:@]

All sounds good in theory - I've yet to get to launch a major invasion - good luck to you

I use the Frag Method since it really isn't possible to account for all the variables precisely
1. Assume about 1500 loadl points/ship
2. Creat a TF with the number of AP OR LST required to load one unit of your force assuming the 1500 limit
3. If the TF status after loading indicate "loading troops" create a new one ship TF and load again
4. Repeat step #3 until the last TF status is "loading supplies"
5. Repeat steps 2-4 for as many additional units as you require for your force
6. Create a TF with one AK for each unit and load supply
7. Combine all of the Task Forces and add fire support ships and escorts
8. If you want a LOT of supply, just let the TF continue loading until it is full; if you only want enought for one day's fighting you can sail away after loading for one full day (but allow that one day or you will not have ANY supply landed with the troops)

Now this will PROBABLY allow you to unload the entire embarked force on one turn.

[Dereck]

To Alikchi: I WANT Saipan. I need Saipan, Tinian and Guam both as mid-Pacific naval bases and air bases for my B-29s.

To Tallyho: I have 3 carrier task groups out there getting ready to pound Saipan. Two are targetting the port and the third ground units.

To answer some of Pompack's points. I'm loading my task forces by unit and after the unit loads will finish loading supplies. I'm also going to add 1 or 2 extra LSTs and a number of LCI's to the assault task forces so they should have plenty of supply going in. In the support/engineer task force which I intend to land once I gain control of Saipan I'm going to have 5 7000 ton AKs ready to land more supplies. If more supplies are needed I've turned Kwajalein into a major supply base (and also my forward naval base after moving from Pearl Harbor) and have 999,999 supplies there with 2 30AK convoyes bringing 216k of supplies each trip. I have spare AKs at Kwajalein so I can easily bring up more supplies when/if needed.

My primary assault force(s) I'm thinking of breaking them down into multiple two-unit task forces instead of one or two big task forces so there will be smaller targets for the coastal guns to fire at. Though I hope to destroy as many as I can with the bombardment and carrier forces I have there now.

The assault force I've been able to completely load on LST-type ships but the floating reserves and support task forces I've used AP and AK (about twice what the load requirements are to speed up loading/unloading).

==== Assault Force(s) ====

TF#1
-- V Amphib Corps
-- 1st USMC Division

TF#2
-- 2nd USMC Division
-- 18th USA Engineer Regiment

TF#3
-- 3rd USMC Division
-- 193rd USA Tank Battalion

TF#4
-- 1st USMC Armored Amphibious Battalion
-- V USMC Corps Artillery

TF#5
-- 56th USA Coastal Artillery Regiment
-- 14th USMC Defense Battalion

==== Floating Reserve ====

** debating whether to have floating reserve in separate unit task forces so they could be fed in piecemeal if necessary **

TF#6
-- 25th USA Division
-- 27th USA Division
-- 40th USA Division
-- 2nd USMC Armored Amphibious Battalion
-- 763rd USA Tank Battalion

==== Support/Engineering ====

TF#7
-- 78th USA Coast AA Regiment
-- 72nd Aviation Regiment
-- 804th Engineer Aviation Battalion
-- 56th SeaBees
-- 67th SeaBees
-- 74th SeaBees

[51st Highland Div]

I would go for Tinian and Guam first and use these to launch air strikes using B29s and all those SBD and TBM USMC Squadrons.Also you can base your bombardment TF's close at hand and run them in several times a week to soften up the place before attempting a landing.I would grab all those SeeBee units and pack these into Tinian and Guam to build up those bases ASAP.....

[patrickl]

Hi,

Personally, I would bypass Saipan.. it is just too strongly held. I don't think it is worth it.. If Tinian and Guam are lightly defended, they present better targets.[;)]

[saj42]

Looking at typical assault values for the types of units defending Saipan, I estimate 1500 AV. Assuming they are unsupplied then 25%, defending in Cm hex x3 = 1100AV or thereabouts. You are going to want to get 2000 AV on the beach ASAP.

Someone please correct me if i'm wrong [&:](which is highly probable)

[51st Highland Div]

Ha just bypass Saipan and launch an assault on Iwo Jima instead [;)]

[tsimmonds]

ORIGINAL: Tallyho!

Looking at typical assault values for the types of units defending Saipan, I estimate 1500 AV. Assuming they are unsupplied then 25%, defending in Cm hex x3 = 1100AV or thereabouts. You are going to want to get 2000 AV on the beach ASAP.

Someone please correct me if i'm wrong [&:](which is highly probable)

My SWAG was also 1500. As for the rest of your calcs, your guess is as good as anyone's. It all depends on the supply state. Course on very hard the AI doesn't seem to need supply. IJ has lots of support squads present. They will recover disablements, disruption and fatigue rapidly on turns there is no assault combat. The US units will need lots of supply and support, otherwise it is possible that IJ could manage to out-recover them in between assaults. I'd include some big aviation support units and some more HQs as early as possible, just to have more support squads available. A few big naval bombardments will disable support squads very nicely. This would be another reason to take Tinian or Pagan first; it gives you a handy nearby spot to replenish ammunition for the bombardment forces, which otherwise will have to return to Eniwetok (or wherever).

[Dereck]

ORIGINAL: irrelevant

ORIGINAL: Tallyho!

Looking at typical assault values for the types of units defending Saipan, I estimate 1500 AV. Assuming they are unsupplied then 25%, defending in Cm hex x3 = 1100AV or thereabouts. You are going to want to get 2000 AV on the beach ASAP.

Someone please correct me if i'm wrong [&:](which is highly probable)

My SWAG was also 1500. As for the rest of your calcs, your guess is as good as anyone's. It all depends on the supply state. Course on very hard the AI doesn't seem to need supply. IJ has lots of support squads present. They will recover disablements, disruption and fatigue rapidly on turns there is no assault combat. The US units will need lots of supply and support, otherwise it is possible that IJ could manage to out-recover them in between assaults. I'd include some big aviation support units and some more HQs as early as possible, just to have more support squads available. A few big naval bombardments will disable support squads very nicely. This would be another reason to take Tinian or Pagan first; it gives you a handy nearby spot to replenish ammunition for the bombardment forces, which otherwise will have to return to Eniwetok (or wherever).

When it comes time to replenish my ammunition I have 10 more battleships at Kwajalein I can send to keep the pressure up. If I have to bombard Saipan for a month or more before I invade I'll do it.

[racndoc]

Im getting ready to invade the Marianas in the next month or two in a PBEM. Assume that that the Japanese are at level 9 entrenchment.....that really reduces the effects of your bombardments. I have found that aerial bombardments of CD units are relatively ineffective unless you can bombard the island for a minimum of 3-6 months and get the units completely out of supply. I have found that it is more effective to have your land and naval based bombers set to hit ground units. Take 12-16 BBs and make 3-4 bombardment TFs, hit the island every turn with 1 TF...that will always hit the base units. On the turn of your invasion you can send more than 1 bombardment TF and then after the 1st TF hits the base units the other TFs will hit ground units. It looks like there are substational defensive forces on Saipan...I would send enough troops to achieve at least a 4:1 advantage.

[tsimmonds]

What has your bombing target been? To get results vs CD from the air, you have to bomb the port. Ground attack goes after the boys on the front line.

[Tom Hunter]

I agree with Spruance, bombard it for weeks and weeks. Then bombard it some more, and hit it with airpower too.