Kazec wrote:
Stepping forward, I would like to seek clarifications on the radar configuration in 1942 since most photos I found had the radar censored. From what I read, the Helena carried a SC radar and a SG radar on her foremast. When was the radar changed to CXAM type?
Besides, What are the differences between the 1943 and 1942 configurations? I learned that she was overhauled in Sydney in Feb 1943 and some modifications might be made during that occasion, perhaps the radar was changed? The Niko kit claims to be 1942 fit but I cannot find much differences (errors aside) from my Profile Morskie’s 1943 plan.
To the best of my knowledge Helena carried her SC set to the end. The "X" in CXAM was for "experimental". Only 6 CXAM sets were produced. They were carried by Yorktown, California, Pensacola, Chicago, Chester, and Northampton. California's set was relocated to the Hornet after Midway. At some point Northamption's set was replaced by a CXAM-1, but I haven't been able to find out exactly when and why, and this specific substitution (CXAM-1 for CXAM) appears to have been unique. I am not sure how many CXAM-1 sets were produced, but while there were more of them than the 6 original CXAM's, their numbers were still very limited. SC was supposed to be the "production" set, but in actual service was found to be inadequate for the task. But until the SK became available, variants of the SC were all that could be installed in numbers. Radar installations on US ships were almost never done in non-US yards, no matter how friendly the nation. Also few, if any, mods were done outside of US shipyards. The period Helena spent in Sydney was probably more to correct issues, such as fixing the field repairs from the Nov 13 '42 battle and other "wear-and-tear" items. Sydney was very busy during this period just keeping up with the emergency temporary (or in some cases permanent but incomplete) repairs to battle damaged ships from all of the allied powers fighting at Guadalcanal. US ships requiring limited mods usually went to Pearl Harbor. The more extensive mods were done on the US west coast.
One thing that has always bothered me about plans drawn up for the Helena is the width of the open bridge added in early '42 at Mare Island. If you look at the bow shot on the inside back cover of the Profile Morskie book, note that the rangefinder for the MK-34 director is noticeably wider than the face of the open bridge. NOBODY ever draws the plans that way, and if you look at the Profile Morskie plan view, the bridge is wider than the rangefinder. The open bridge is drawn too wide, and that carries down through all of the lower bridge decks. The bridge was redesigned from the original Brooklyn plan specifically to allow the forward 5" twin mounts to fire at aircraft directly ahead of the ship. The plans show the bridge wings at the pilothouse level overhanging the inboard barrels of the 5" mounts. That is wrong. The 5" guns elevated together, and that would have prevented even the outboard guns from elevating to fire on high targets forward. This width mistake throws off a few other bridge block proportions as well.