Do you have links to those handy? I’m curious what the specific unique failures happened here beyond “building it before designing it” and “changing it while building it” and “modifying a design so much that it would have been easier to start from scratch after all.” I’m not being snarky, I’m just working 16 hour days right now and will lack the time and energy to go digging for myself until January or so.
I’m not entirely familiar with the Legend Class cutter. I am assuming that by having two diesels and a single gas turbine it has inward turning screws and while using the gas turbine the shafts act as a single unit.
Inward turning screws are more efficient but manoeuvrability suffers.
History is replete with frigates being designed to serve as destroyers or even cruisers
and not functioning in any capacity satisfactorily apart from an ability to drain the accounts of the exchequer.
As noted in my previous post, there isn’t really a single comprehensive source that brings everything together.
TWZ article from 2021, about 17 months after DD&C contract award, gives a good overview of the differences between the FFG-62 and the FREMM parent at the time of the contract award. New Diagram Details How The Navy's Frigate Will Differ From Its Italian Parent's Design
May 2024 GAO report: https://www.gao.gov/assets/gao-24-106546.pdf
Keep in mind, the GAO are smart folks, but are effectively semi-knowledgable laymen when it comes to industry specifics–they can’t have expertise in every area they investigate. Think of them like you would someone who has worked in another field and you have to explain your industry to them–they’ll get the big picture, but key elements often go unnoticed or are misinterpreted. The GAO also tends to focus on the government side of the equation for a couple of reasons–(1) it’s easier to get cooperation and data from agencies than it is from industry and (2) that’s the arena Congress and the Executive branch have direct control over. Kind of like the joke about the guy looking for his keys under the streetlight, because that’s where the light is.
The GAO pretty much ignores the industry responsiblity for selecting the parent, executing the actual concept/functional design, and developing the detailed design. You’ll find very little in the report about the contractor’s performance.
Seapower Committee testimony from 25 March 2025: https://www.armed-services.senate.gov/imo/media/doc/32525seapowertranscript.pdf
Pay particular attention to pages 26-27, but the entire transcript is worth reading.
Hopefully this helps,
Doug
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Propeller rotation is typically tested in both configurations and selected based on which one has the marginal advantage in propulsive efficiency. The type of prime mover is irrelevant in this context.
As for the other part of your question, there is a cross-connect gear to allow the GT to power both shafts. That configuration is used in a variety of ships and typically looks something like this
Doug
So no VLS on these new frigates or any kind of fixed missile load. Makes them pretty damned near useless to fleet than they should be and rather just like the miserable LCSs they are to take the place of right down to the modular mission packages nonsense.
Navy’s New Frigate Will Not Have A Vertical Launch System For Missiles