Proper Course

A LTW-guest post by Brass

Proper Course in the Rules

There are only three rules where proper course is mentioned. These are:

• Rule 17: overtaking to leeward …
• Rule 18: Mark-Room
• Rule 23: Interfering with another boat.

Additionally, rule 14(b) relies on the definition of mark-room, which in turn relies on proper course.

If there is no alleged or apparent breach of one of these rules, then 'proper course' has no meaning. If a Protest Committee's conclusion and rules that apply in a protest does not refer to one of these rules then the term 'proper course' should not be used.

What is Proper Course - Proper Course and Best Course

Proper course is defined as 'A course a boat would sail to finish as soon as possible in the absence of the other boats referred to in the rule using the term.'

Note that a boat can have more than one 'proper course', for example, either gybe may be equally favored for a boat on a downwind leg, but usually, in the context of a proper course rule there will be only one relevant proper course.

Let's see how the definition of proper course is made up.

Let's define Best Course as 'the course a boat would sail to finish as soon as possible'. A boat's best course is the course the boat would sail to avoid obstructions, and not break any rules.

A boat's proper course then, is the boat's 'Best Course', but not allowing for rules-tactical or wind/water-strategical effects of other boats referred to in an applicable proper course rule.

Let's look at a few diagrams.

Figure 1. Boat reaching to a mark alone

This boat's best course will be on, above or below the direct course to the mark depending on wind, tide, characteristics of the boat and so on.

If the boat was alone, beating to windward, its best course would be close hauled: it could be a little pinched, or a little free, again depending on wind, tide, characteristics of the boat and so on.

Figure 2. Boat reaching past an obstruction

This boat's best course will be to sail round the obstruction, on one side or the other, depending on the wind, tide, characteristics of the boat, and wind shadow of the obstruction and extra distance to be sailed

Figure 3. Overtaking a slower boat

Racing boat Blue with poorly trimmed sails is sailing slower than Yellow. Yellow, clear astern must keep clear of Blue. Yellow's best course will be to sail to windward of blue, avoiding Blue's wind shadow.

No proper course rule applies here so the notion of proper course is of no use.

Figure 4. Overtaking at an obstruction where Rule 17 applies

Yellow, reaching faster clear astern becomes overlapped to leeward within two of her hull lengths to leeward of Green, so rule 17 applies to oblige Yellow not to sail above her proper course.

Rule 17 which is a referring to proper course applies, so Yellow has a proper course.

Approaching Blue which is sailing slower, Yellow, clear astern must keep clear of Blue. Yellow's best course will be to sail to windward of Blue. This would be Yellow's best course whether or not Green was there; therefore Yellow's best course is also her proper course.

Although this will disadvantage Green, by forcing her to sail high, and make it easier for Yellow to break through Blue, as long as Yellow sails no higher than will get her past Blue fastest to the next mark, Yellow does not break rule 17.

Figure 5. Where Rule 17 applies without an obstruction

Yellow, reaching faster clear astern becomes overlapped to leeward within two of her hull lengths to leeward of Green, so rule 17 applies to oblige Yellow not to sail above her proper course.

Rule 17, which is a referring to proper course, applies, so Yellow has a proper course.

Yellow wants to take advantage of her better boat speed to get further ahead of Green and gain good position for her mark-rounding. To do this Yellow's best course is to sail high, pushing Green further up to windward.

But sailing high to windward would not be Yellow's best course in the absence of Green. Thus Yellow's best course is not her proper course. If Yellow sails any higher than she would have to get to the mark as soon as possible, she breaks rule 17.

Of course, if a strong lift arrived, which Yellow wanted to follow up, or a right of way boat arrived that Yellow had to keep clear of, responding to these things by sailing high, would be Yellow's proper course.

Figure 6. Where rule 17 does not apply

Suppose Green has sailed high of the mark and found a wind gust and is sailing down on the gust.

At position 3 Green, the windward boat must keep clear of Yellow. Yellow's best course is to sail high to avoid being blanketed by Green.

No proper course rule applies here so the notion of proper course is of no use.

Right to Sail Proper Course or Obligation?

The only rule which gives a boat a right to room to sail its proper course is rule 18.2 Giving Mark-Room.

Other rules restrict a boat in respect of its proper course. When they apply:

• Rule 17 restricts the leeward boat from sailing above its proper course.
• Rule 18.4 restricts they right of way boat from sailing beyond her proper course without gybing.
• Rule 23 restricts a boat that may interfere with a boat taking a penalty or sailing another leg, to her proper course.

Except when rule 18.2 applies, no rule gives a boat an entitlement to sail her proper course. Any entitlement a boat has to sail her best course, comes from her having an entitlement to right of way or room under one of the other rules.

Protest Committee deciding what a boat's proper course is

It may be difficult for a Protest Committee to decide what a boat's proper course is. A boat's proper course will be affected by the factors discussed above.

There is no onus on any boat to prove facts in a protest, but a boat protesting another boat for breaking a proper course rule (rules 17, 18.4, or 23) or a boat protesting that she has not been given room to sail her proper course at a mark (rule 18.2), may be expected to provide relevant evidence and advance necessary arguments to support her contentions about proper course.

Whether or not a boat protesting another boat for breaking a proper course rule (rules 17, 18.4, or 23) observes that the course of the protestee is different from her own best course, or prevents her from sailing her best course does not decide the proper course of the protestee. If the boats are of the same or similar design, it may be indicative, but possibly different boat characteristics and the judgement of the skipper of the protestee must be taken into account.

Customarily Protest Committees give substantial latitude to a boat justifying her proper course. A possible standard for deciding proper course may be:

Given that there may be legitimate differences of opinion about what a boat’s proper course may be (Case 14), the standard to prove proper course requires a reasonable hypothesis explaining why the course sailed was the course the boat would have sailed to finish as soon as possible in the absence of the other boats referred to in the rule using the term, that is consistent with the facts and not effectively undermined by counter argument.

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