Monday, 12 December 2011

(pillow)Case of the week (48/11) – 33

(This is an instalment in a series of blogposts about the ISAF Case book 2009-2012 with amendments for 2010. All cases are official interpretations by the ISAF committees on how the Racing Rules of Sailing should be used or interpreted. The cases are copied from the Call book, only the comments are written by me.)

(pillow)Case picture


Rule 19.2(b), Room to Pass an Obstruction: Giving Room at an Obstruction
Rule 19.2(c), Room to Pass an Obstruction: Giving Room at an Obstruction
Rule 20.1(b), Room to Tack at an Obstruction: Hailing and Responding
Rule 20.3, Room to Tack at an Obstruction: When not to Hail
Definitions, Clear Astern and Clear Ahead; Overlap

A boat that hails for room to tack before safety requires her to tack is entitled to receive room under rule 20.1(b), but by hailing at that time she breaks rule 20.3. An inside overlapped boat is entitled to room between the outside boat and an obstruction under rule 19.2(b) even though she has tacked into the inside overlapping position.


Assumed Facts for Question 1

There are breakwaters projecting from the shore at fairly regular intervals with a reasonable amount and depth of water between them. To be competitive when beating against a contrary current, it is advantageous to tack into and out of the area between adjacent breakwaters. SL and SW, small keel boats, enter one such area overlapped, close-hauled on starboard tack. In the absence of SW, SL would tack at a point where, on port tack and close-hauled, she would just clear the end of the farther breakwater.

Question 1

If SL were to hail for room to tack at position 2, would SW be required to respond as required by rule 20.1(b)?

Answer 1

Yes. However, because at position 2 SL is not yet in danger of running aground, she would break rule 20.3 if she hailed SW for room to tack at that time. To avoid breaking rule 20.3, she must not hail until safety requires her to tack.

Additional Assumed Facts for Question 2

SL does not hail for room to tack. However, SW tacks between positions 2 and 3 at a point where, after she completes her tack, her close-hauled course passes just to leeward of the end of the farther breakwater. Seeing SW tack, SL immediately tacks as well.

Question 2

After position 2, is PL (formerly SW), required to give PW (formerly SL) room between her and the breakwater?

Answer 2

Yes. When SW tacks, SL is able to tack without breaking a rule. When SW turns past head to wind, the overlap between her and SL ceases to exist, because they are then on opposite tacks and sailing at less than 90 degrees to the true wind (see the definition Clear Astern and Clear Ahead; Overlap). A new overlap begins when SL passes head to wind, at which time the boats are once again on the same tack. After the new overlap begins PL, by bearing off, can easily give PW room between her and the breakwater. Therefore, rule 19.2(b) applies and requires PL to give PW that room.

Although the breakwater is a continuous structure from the shore to its outer end, it does not qualify as a continuing obstruction because the boats pass close to it only briefly, near its outer end. Therefore, rule 19.2(c) does not apply.

RYA 1975/8


Rule 20 is a safety rule and when used by a boat the hailed boat has only two options: Either tack as soon as possible or answer: “You tack” and subsequently give the other boat room to tack and avoid her.

If the hail is inappropriate – like it would be in question 1 in case 33 – the hailed boat still has to respond correctly. But when is it inappropriate?

Please consider you answer in the following situations: Must the hailed boat respond according to rule 20.1(b) or not, when;

  1. The hailing boat is sailing on a reach approaching an obstruction?
  2. The hailing boat is sailing above close hauled (pinching) approaching the finish vessel, while the hailed boat can fetch the finish?
  3. The hailing boat is approaching a rounding mark of the course?
  4. The hailing boat is an floating object in the water that is not an obstruction?
  5. The hailing boat is approaching the end of a pier that can be passed by luffing 15 degrees for three seconds?

Hint: The answers can be found in the wording of the rule……



Case33 answerpic


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