I reviewed some original source documents at the HMS Hood Website (After Action Reports by Capt. Leach - PoW, Capt. Ellis- Suffolk, Adm. Wake Walker - Cruiser Squadron 1 Norfolk and Suffolk, and a report on the test of the Hoods Type 279 when it was installed in early 1941). I don't think that my alternate scenario that started this thread has merit. Here's my reasoning:
1. A plan under which instead of engaging Bismarck at Denmark Straits, Holland shadows her with Hood, PoW, Norfolk, Suffolk and the 6 destroyers, and leads Tovey's force to an engagement where both Tovey's and Holland's forces combine to sink Bismarck within 24 hours, would be a radical departure from the traditions and doctrines of the Royal Navy that dictated immediate and aggressive action.
2. Holland and Tovey's new plan would come under intense scrutiny by politicians and the public as well as their peers. If it failed and Bismarck got away, the charges would range from incompetence to cowardice, and the consequence might be Court Martial.
3. As a result, Holland and Tovey better have damn good reasons to justify their plan. I started the thread to list what I thought were justifying reasons for this different plan.
4. Such reasons can only be based on things Holland and Tovey knew or had high confidence in before the time of the Denmark Straits battle.
5. Radar is the lynchpin of my alternate plan. I suggested that three shadowing radars on Hood, PoW and Suffolk would make Tovey and Holland (as I variously expressed it) certain, almost certain, or reasonably certain that Bismarck would be tracked constantly on radar during the 24 hours would take for Holland and Tovey to trap Bismarck between them. Without this it fails.
6. The Denmark Straits was the first time that radar was used in at sea for warfare. While Tovey and Holland knew certain things about it, they did not have know enough about its capabilities, limitations and effective use to enable them to form any opinion on whether it could do item 5 above, let alone quantify the degree of certainty.
7. In early 1941, The Hood's Type 279 detected Nelson at 9 miles in a test under poor conditions. That's about 17,500 yards. That is not long enough for my plan to work. Hood would have to shadow within mutual gunfire range and if, as was likely, Bismarck was faster than Hood, she could outrun its coverage. That takes one of the additional three radars out of the picture.
8. The 25,000 yard range for Type 284 on PoW and Suffolk was a surprise discovered by Suffolk in the Denmark Straits. That was too late for 25,000 yards to form the basis of any alternate plan.
9. 25,000 yards wasn't good enough anyway. Afterward Captain Ellis recommended staying within 3/4 of that distance to provide a cushion against unexpected maneuvers, and then noted that this placed him within gunfire range. This was learned after the battle.
10. 25,000 yards for PoW would present the same problem as Hood in item 7 above. In fact, I guesstimate that the effective range would have to be 50,000 to 100,000 yards to prevent outrunning at say a 2-3 knot differential speed over 24 hours. Scratch additional radar No. 2 as a basis for a plan.
11. Tovey and Holland would know ahead of time that radar was new, so the practices and procedures in place to assure its effective use in combat were incomplete and there was a lot to be learned. Hardly a thing to rely upon. What still needed to be learned is illustrated by Captain Ellis' Report. He notes that returns from several ships in a sweep can be easily confused in future sweeps. So he recommends for the future something basic and obvious - plot all returns from each sweep on a chart so you have them all in the same place at once and can tell one from another with one look.
When my kids did their science projects I always told them that it didn't matter whether their hypothesis was proven or not. What matters is whether the process was sound enough so that you can be sure that you can learn something from either result.