I would like to bring this analysis to this discussion. Rule 45 is not really a list of unrelated prohibitions. Its provisions are connected by a common concept: a boat must remain a racing boat, using the racing environment only within the limits expressly permitted by the rule.

We should analyse the clauses separately for application, but interpret Rule 45 as one coherent rule for its purpose and structure.

If we step back from the individual clauses, I think the central idea of Rule 45 is control of the boat’s physical relationship with the outside environment while racing.

The rule establishes a basic racing condition:

That explains why the paragraph contains several seemingly different ideas.

The structure makes more sense this way

1. Establish the normal condition
The boat starts racing afloat and off her moorings.

2. Prevent external support
After the preparatory signal, she cannot be hauled out or made fast, except for the specified necessities such as bailing, reefing or repairs. 

3. Allow two specific physical interactions
The rule then says:

Those permissions are important. They show that Rule 45 is not simply a prohibition against stopping, touching the bottom, or interacting with something outside the boat.

4. Control the consequence of anchoring
If she anchors, she must recover the anchor before continuing, unless unable to do so. 

So the underlying concern is not “never stop the boat.” It is closer to:
Don't use being attached to, supported by, or in contact with the environment as an uncontrolled means of racing; where the rules expressly allow such contact, stay within the limits of that permission.

This also explains “standing on the bottom”

This is why I would resist interpreting “the crew may stand on the bottom” as merely an accidental-grounding provision.

The rule deliberately grants that permission.

So if a sailor is in shallow water and stands on the bottom while holding the boat, the starting point should be:

Only after that do we ask:

That second question could engage Rule 42 or another rule like any of the Part 2.

This is similar to the logic in World Sailing Case 5: the fact that Rule 45 permits anchoring does not mean every movement associated with an anchor is automatically permitted. The Case distinguishes the permitted recovery of an anchor from using that recovery to propel the boat beyond the permitted effect. 

So I would formulate the “main idea” of Rule 45 as:
Rule 45 regulates the boat's use of external physical support while racing: it prohibits being hauled out or made fast, but deliberately permits anchoring and standing on the bottom within the limits established by the rule.

 "So, it's the WS 2029 Draft for me! "

Ditto. I'm using the WS 2029 Draft going forward in NOR/SIs, especially for international events.

It is only a shame that WS cannot see their way to using their own draft. :)

Kim,

In the original post, there are exactly two boats displayed. If we stick to that situation, Blue has heaps of room to avoid, as does Yellow after she tacks. But only for a specific class of boat with known maneuverability characteristics.

As to a "seamanlike manner", one has to specify the boats to even start to discuss this. For many years I raced small and nimble boats that could turn 90° in a boat-length and easily sail dead downwind in a very seamanlike manner. In the original, sailing dead downwind would easily allow Blue to keep clear.  I also spent a decade aggressively racing a 60' schooner that required 120' and many seconds (even minutes in light air) to turn 90°.  In the Original post, if we're discussing my 60' schooner, as Yellow and a similar boat as Blue, then a prudent skipper aboard Yellow would tack far later than is shown in the original post or would be forced by Rule 15 to slow their tack so that Blue could pass.

In the fleet racing situation you've added to the thread, it could be unwise for Yellow to tack into the wall of approaching Port tack boats along with Blue, but Yellow would NOT be breaking a rule in doing that. Indeed, this is a regular maneuver in team-racing for the leader to get onto starboard after the leeward mark rounding and force the competition away from the mark. Thus, it could be a tactical error but once Yellow has established herself on starboard, the responsibility shifts to all the port tack boats. (Again, this would all depend on the maneuverability of the type of boat in question.)

Do note that the question of a "seaman like" doesn't come into play when there is clearly time for Port tack boats to avoid, even if that requires that they head up aggressively, gybe, or even stop. Claims of poor tactics and strategy do not alter the racing rules.

A final comments, NOT related to the original question. You've stated that "In fleet racing , hard luff and crash jibe are not considered seamanlike way maneuvers." First, I'd like to point out that there is no place in the rules that I can find that appears to support this sentence. Both "hard luff" and "crash jibe" could be "seamanlike" or not depending up the boat, the crew, and the conditions. Going back to the dinghy vs the 60' schooner example, it's obvious that knowledge of the boats involved is crucial. You did describe your thoughts were for ILCA and Opti classes. In your diagram, what is a much more likely scenario is that Red and Blue could end up in a pin-wheel around the mark, Green can easily head up and pass to windward of Yellow. Turquoise and Gray have plenty of time to realize that there is a starboard tack boat coming and to take seaman like action to avoid fouling Yellow. I agree that it might be stupid for Yellow to tack into the face of a herd of port tack boats, but Yellow doesn't seem to be breaking any rule.

Thanks Paul ... that sounds like a lot of headache. Makes filtering out the daily spam-posts look like a walk in the park. 

Phil, How do you conclude that W was not required to act to avoid contact until it became clear that L was not keeping clear?

L was the right of way boat.  She was not  required to keep clear.

W was not entitled to room.