Truk is already in Japan hands, correct?
Correct. It has been since 1918 IIRC and has been developed as Japanese fleet base since the 1920s.
Would it be worth it to Invade there before it can be used to cut off American/ Austrailian Shipping? It is a major base, comparable to Pearl for the IJN.
Operation Hailstone - Wikipedia
Of course, the IJN losing that forward base may prevent a few battles from taking place.
Absolutely not this early.
Right now the fleet carrier numbers in the Pacific are 5-3 IJN (Sara's damaged, Kaga's sunk, Hornet and Wasp are unavailable). CVL and BB numbers are comparable to worse with ships damaged and needing repair like Ari eating a torpedo. Any kind of USN counterattack before mid to late 1942 is begging to get the KANTAI KESSEN treatment from a equal to superior IJN as the USN fights away from their bases.
Basically for the next few months to a year of the war, the USN will be fighting primarily on the defensive with limited counterattacks to try to thwart IJN offensives and pick off weak points. The USN doesn't have the fleet oilers, ships, airpower, and basing
yet to actually start a serious offensive, although the strategic situation is better than IOTL (fewer losses at pearl, Wake held, Kaga sunk). Now once the 'ordered in 1940' construction arrives like the first Essexes, Independences, and NorCals/SoDaks in 1941-43, followed by the 'war priority construction' AKA
ALL THE SHIPS EVER 1943-45 then it's time to wrest the initiative away from the IJN and beat them over the head and shoulders with it until they submit.
This is true, but the Japanese showed that it was possible, on an albeit smaller sacle with the USS Stewart, who after being severely damaged in the battle of Badung Strait was put into a floating dry dock in Surabya, but wasn't properly secured so she toppled onto her side in the dry dock causing more damage. Decding that she couldn't be saved she was scuttled with demolition charges and then the dry dock she was in was scuttled aswell. She sat on the bottom of Surabya bay for almost a year before being raised and rebuilt by the japanese. She was eventually recaptured by the US at the end of the war.
True, it is not impossible, but highly impractical. The USN will need those drydock slots for their own cap ships like half of Battleship Row (Oklahoma, Wee Vee, and Arizona for sure), and the materials and manpower to renovate Kaga will be coming from other easier projects that yield more value.
Assuming her magazine doesn't cook off and the fire stays in her upper works, her engineering works and auxiliary controls could still be operational and if she doesn't have any long lances slammed into her side before she can be captured and the fire has gone out she could be steamed under her own power back to Pearl Harbor. There she could get stop gap repairs so that she could reach a west coast ship yard and if she doesn't have any damage below the water line she wouldn't need to take up dry dock space. Tie her up at the dock and then start taking cutting torches to everything above the main deck. This will allow the installation of an american spec hanger, elevators, and flight deck. In terms of AA armament she could get the Chicago pianos that are now being phased out for 40mm and 20mm's. This all assumes that the fire stays in the upperworks and she doesn't suffer damage below the waterline though.
That's a lot of assumptions, and also assumes that the Japanese don't simply steam or tow her back to Kure after the fire burns itself out.
The other problem is every West Coast shipyard (and East Coast shipyard, and Gulf Coast shipyard) will be incredibly busy with both emergency repairs of damaged USN ships and emergency wartime production of new USN ships. Full stop. Newport News Shipbuilding (who built Little E and her sisters) built
243 ships under naval contracts 1941-45, and
had to build an auxiliary shipyard from scratch in North Carolina just to have space so that they could build ships that were demanded. That's just one company as a representative example of the Arsenal of Democracy at work.
There was an
incredible shortage of trained, untrained, semi-trained and "fuckit when can you start work for us?" level manpower in the US shipbuilding industry (and US industry in general!) during WWII. A large part of the reason women and blacks entered the workforce then in such massive numbers was the demand for people to fill the jobs was so great. It is no exaggeration to say that most of the shipyards ran nonstop 24/7/365 from shortly after Pearl Harbor until Spring 1945 when the US Navy took the foot off the gas and started cancelling orders for ships that would not be completed before Japan would be invaded.
These are the official naval numbers for the USN 1938-1945 (keeping in mind that the Japanese and Germans were sinking ships as fast as they humanly could during the war) 1938:
380 1939:
394 1940:
478 1941 (on December 7th):
790 1942:
1782 1943:
3699 1944:
6084 1945 (V-J Day, end of the war):
6768. That doesn't count ships that were ordered and construction started before being canceled like the final two Iowas, the Montana-class BBs, the later Alaska-class CBs, the late-flight Essex-class CVs, etc etc.
EDIT-Looking at the numbers from
US Ship Force Levels always makes me shake my head. The US Navy
doubled in size 1941-42, then
doubled in size from that in 1943 and grew by an additional 50% in 1944, by which point the naval war in the Pacific was over. The numbers for individual ship classes are equally staggering. CV 7, 4, 19, 25, 28. CVE 1, 12, 35, 65, 71. And so on and so forth. An unstoppable tide of steel indeed.
Kaga is fortunate that she goes to the bottom while believing that thanks to her Japan can win the war. For Hiryuu, Zuikaku, Akagi, and the others, they won't even have that cold comfort when death comes for them.
