Rule 18.1, Rounding and Passing Marks and
Obstructions: When this Rule Applies
Rule 18.2(a), Rounding and Passing Marks and Obstructions:
Giving Room; Keeping Clear: Overlapped – Basic Rule
Rule 18.2(c), Rounding and Passing Marks and Obstructions:
Giving Room; Keeping Clear: Not Overlapped at the Zone
Rule 18 begins to apply when boats are about to pass a mark or obstruction;
the distance from the mark or obstruction may vary depending on sea and wind
conditions. However, the obligations between boats may still change before one
of them reaches the two-length zone. It is only at the two-length zone that
it can be determined whether rule 18.2(a) or rule 18.2(c) will govern the rounding.
Summary of the Facts The diagram shows the positions of three dinghies that fly spinnakers at four moments in time as they approach a leeward mark. At position 1, B is about four hull lengths from the mark, C is overlapped with B and clear ahead of A. C hails that she is about to round the mark and that A has no overlap. She acknowledges B’s overlap. C then proceeds to lower her spinnaker. At position 2, B reaches the two-length zone clear ahead of C and A. A now has an overlap on C. At position 3, C reaches the two-length zone overlapped with A and clear astern of B. C is still lowering her spinnaker and slowing down to allow B to round ahead. At position 4, C is not allowing A room to pass the mark. |
Questions
When did rule 18 begin to apply? For each of the four positions shown in the diagram, what rights do the boats have and which parts of rule 18.2 apply?
Answers
Rule 18 begins to apply between a pair of boats when they become‘about to pass’ a mark or obstruction. The meaning of this phrase is discussed in Case 84.
In position 1, whether these boats are ‘about to pass’ the mark or not depends on the circumstances. If the boats are moving fast due to either strong wind or favorable current, or if the boats are involved in lowering their spinnakers in preparation for passing the mark, then they are ‘about to pass’ the mark at this point.
In such circumstances, rule 18.2(a) requires C to give room to B to pass the mark, and rule 12 requires A to keep clear of both B and C. Rule 11 also applies between C and B.
However, if the wind is moderate, and there is no current or adverse current
and if there is no necessity at that time to begin to lower spinnakers in preparation
for passing the mark, then at position 1 the boats are not ‘about to pass’ the
mark. Under such conditions, rule 18 does not apply. C holds right of way over
B under rule 11 and both C and B hold right of way over A under rule 12.
If all three boats are ‘about to pass’ the mark at position 1, then
the applicable part of rule 18 can change before any of the boats reaches the
two-length zone. An example of such a change occurs between positions 1 and
2 in the diagram. When B pulls clear ahead of C between positions 1 and 2, rules
18.2(a) and 11 cease to apply between C and B and rule 12 begins to apply between
them. At position 2, when B reaches the zone, rule 18.2(c) begins to apply between
B and C and between B and A. After B enters the zone, both C and A remain obligated
to keep clear of B, even if one or both of them obtains an overlap on B later.
Finally, when A obtains an overlap on C, C becomes obligated by rule 18.2(a)
to give room to A.
If a pair of the boats is not ‘about to pass’ the mark at position
1, then rule 18 does not begin to apply between them until both are ‘about
to pass’ the mark. Until that time, right of way between the pair is governed
by rule 11 if they are overlapped and rule 12 if they are not. At position 3,
B and C are ‘about to pass’ the mark and, therefore, both rule 12
and rule 18.2(c) apply between them. If A is not yet ‘about to pass’
the mark, she is required by rule 11 to keep clear of C and by rule 12 to keep
clear of B. As soon as A does become ‘about to pass’ the mark, then
she becomes obligated by rule 18.2(c) to keep clear of B, and C becomes obligated
by rule 18.2(a) to give A room to round the mark.
At position 4, all the boats are subject to rule 18. Both C and A are fulfilling
their obligations under rules 18.2(c) and 12 to keep clear of B. However, the
diagram indicates that C is not fulfilling her obligation to give A room to
round the mark, and so at that point C is breaking rule 18.2(a).
RYA 1998/4