Fred,
your analysis of "or over" is correct. Seaplanes are expected to keep clear of other traffic while on the water or when going to land or taking off. However, others boaters are governed by rule 2b, which notes that attention must be paid to "any special circumstances, including the limitations of the vessels involved, which may make a departure from these Rules necessary to avoid immediate danger." In other words, at no time should a mariner make a navigational move that is technically correct, but may result in a collision if another vessel is unable to a follow the rules due to special circumstances or the limitations of the vessel. In this case, crossing the bow of an airplane that has just become airborne, but not yet achieved sufficient altitude to avoid a collision would be in violation of rule 2b. The pilot should have planned their take-off to avoid this situation, but once the pilot is committed, other boaters must go by rule 2b and give way to the aircraft until the special circumstances or limitations are no longer a factor.
Rule 2b is a very important rule that not all boaters are sufficiently aware of. The rules allow a sailboat to insist on right-of-way over a heavily laden tanker, but rule 2b would make the sailboat actions culpable in a collision. In reading numerous court findings, never have I found a decision to be all and none, there is always a degree of blame assigned to the vessel that was technically in the right.
your analysis of "or over" is correct. Seaplanes are expected to keep clear of other traffic while on the water or when going to land or taking off. However, others boaters are governed by rule 2b, which notes that attention must be paid to "any special circumstances, including the limitations of the vessels involved, which may make a departure from these Rules necessary to avoid immediate danger." In other words, at no time should a mariner make a navigational move that is technically correct, but may result in a collision if another vessel is unable to a follow the rules due to special circumstances or the limitations of the vessel. In this case, crossing the bow of an airplane that has just become airborne, but not yet achieved sufficient altitude to avoid a collision would be in violation of rule 2b. The pilot should have planned their take-off to avoid this situation, but once the pilot is committed, other boaters must go by rule 2b and give way to the aircraft until the special circumstances or limitations are no longer a factor.
Rule 2b is a very important rule that not all boaters are sufficiently aware of. The rules allow a sailboat to insist on right-of-way over a heavily laden tanker, but rule 2b would make the sailboat actions culpable in a collision. In reading numerous court findings, never have I found a decision to be all and none, there is always a degree of blame assigned to the vessel that was technically in the right.