I am a bit embarrassed to admit, I have been behind on this subject. My post from Saturday, linked the 19 September version of the report, but there was already a more recent version, dated 4 October. You can see it here.
The significant change in this edition is the addition of the new section at the top of page 15. (This new section reflects the questions Tups has raised here earlier.)
“Parent Design and PSC Design
“One potential aspect of the issue of technical, schedule, and cost risk in the PSC program relates to the parent design for the PSC design. As mentioned earlier, a key aim in using the parent design approach is to reduce cost, schedule, and technical risk in the PSC program. As also mentioned earlier, VT Halter states that its winning design for the PSC “is an evolution from the mature ‘Polar Stern II’ [German icebreaker] currently in design and construction; the team has worked rigorously to demonstrate its maturity and reliability.” As also mentioned earlier, VT Halter and ship designer Technology Associates, Inc. reportedly made “a lot of modifications” and went through six design spirals to refine the PSC’s design. Potential oversight questions for Congress include the following:
- “To what degree was Polarstern II’s design a completed and proven design at the time it was used as the parent design for developing the PSC design? How much of Polarstern II’s detail design and construction plan was completed at that time? When did Polarstern II begin construction, and when is the ship scheduled to complete construction and undergo sea trials to confirm the ship’s design and operational characteristics?
- “How closely related is the PSC’s design to Polarstern II’s design? How many changes were made to Polarstern II’s design to develop the PSC design? What were these changes, and what technical, schedule, and cost risks, if any, might arise from them?”
Chuck Hill's CG Blog 
Chuck, I don’t know if you saw this, but they released a Environmental Impact
Statement for the Polar Security Cutter recently that was from March.
Click to access POLAR%20SECURITY%20CUTTER%20FINAL%20PROGRAMMATIC%20ENVIRONMENTAL%20IMPACT%20STATEMENT.PDF
It doesn’t appear to have much of anything special in it, but one thing I noticed, it mentions 25 mm, and more specifically Mk-38 under the gunnery training section, this supports the idea that the PSC will be equipped with Mk-38s.
Justin, thanks, this confirms what we saw on a conceptual design from one of the shipbuilders that did not win the contract. In that concept there were two Mk38 Mod2/3 style mounts, one forward, one aft.
For others who might be interested, here is the section from the document beginning on page 64. It mentions that the PSC is expected to have four mounts, I presume this means they will have two Mk38 Mod? and two .50 caliber machine guns. As is common, there will probably be six locations where the .50s could be mounted.
Sorry, I was unable to reformat this so that it looks right.
2.1.3.11 Gunnery Training
Gunnery training would occur at least 12 nm from shore and potentially in an established U.S. Navy range. The preferred location is in the open ocean, likely in the Pacific Northwest proposed action area. Gunnery training in the Bering Sea would be considered rare and unlikely to occur due to prevailing weather conditions. Gunnery training is expected to occur two times per year. During gunnery training, a PSC would fire inert (i.e., nonexplosive) small caliber, 0.50
caliber or 25 millimeter [mm], gun rounds. A PSC is expected to have four gun mounts. Each mount would fire between 50 and 250 rounds during training exercises. Because gunnery training is expected to occur two times per year,
therewould be a maximum of 500 small caliber rounds expended annually as a result ofthis training. Rounds may be fired at a “killer tomato” target, a 10 foot (f3 meter) diameter red balloon, which would not be retrieved. The entire training would take over an hour, but the actual firing of gun rounds would take approximately 30 minutes. During training,the PSC would be transiting between 6 and 10 knots.
A PSC would also carry MK38 standard system rounds, which are high explosive rounds. MK38 standard system rounds are for use only during emergencies and not during training and thus, are not part of the Proposed Action and are not discussed further in this PEIS.
This CRS report was updated 17 Dec. You can still see it using the same link in the original post.
The report was updated again on 5 February. If you’re only interested in changes, “tracked changes” version can be found here:
https://www.everycrsreport.com/reports/RL34391.html
Some obsolete parts, such as “Aiviq being offered for lease”, have been trimmed from the article.
It’s interesting how hull form is still not considered “mature technology”.
The Germans have officially cancelled Polarstern II:
https://www.awi.de/en/about-us/service/press/press-release/call-for-tender-procedure-for-the-construction-of-a-successor-to-the-icebreaker-polarstern-has-been.html
So much for the PSC reference design being “in design and construction”.