Check out team race call G1.

Steve

Yea, I'd seen that one Steve. One can imply an answer to my Question by that Call, but it doesn't actually come out and say that to be B-T-L it has to be filled one side or the other.

So, take their Question #3 and imagine a boat with their traveler full to one side and sheet tight such that the boom's end is over the port transom corner and the wind is coming over that same corner. With a flick the main is filled on one side of the material or the other, but the boom does not change position significantly .. so she's flipping from port to starboard based on that call even though she is sailing deep downwind and her boom stays on the port side of the boat.

I find that interesting .. Ang

Team Race Call G1

Hi Guys

Look at definitions 'Leeward and windward' and 'Tack'..
If her boom was over the port quarter even tho'sailing by the lee the port side is her leeward side.
Her windward side is starboard so she is on Starboard tack.
Don't think the side which the sail is being fluttered by minor changes in the apparent wind direction is material.
OK?
Simon RJ

Simon, did you review the Team Call that Steve referred to? (link supplied in my last comment). - Ang

How about this as a general understanding of the term as further refined by the Team Call G1. It was an interesting challenge to find a concise way of describing how the mainsail needs to be filled. Anyone else have a clever or better way of describing how the main needs to be filled? I was tempted to use the term/concept of "backwinded" but interestingly that word depends upon the notion of the sail being in a normal position and then filling it on the "wrong side".

Sailing By The Lee: Sailing such that the wind is on the same side of the boat as the mainsail is carried and the wind is filling the mainsail into its aft-facing surface.

Angelo, do not fall into the trap of making it too complicated. :-)

The definition Leeward and Windward talks about 'the side on which her mainsail lies.' It you have to hold it there, or the sail is inverted, is it 'lying' there? There is some real world wooliness when you have a crew member restraining the boom against an accidental gybe, but it is better to be comfortable with some ambiguity than struggle to find an unachievable perfect solution.

Hey Warren ..interesting. So just to be clear, I wasn't suggesting adding a BTL definition to the RRS ... just trying to understand what BTL is understood to mean as implied by Q2 in Team Call G1.

In Question/Answer #2 in the Call G1 they state:

"Port tack. She is now neither running directly downwind nor sailing by the lee."

Why isn't she sailing BTL? Seems to me the only thing that changed about the main is the side it is filled. (I think we can take the crew-holding the main out of the question as we can think of a traveler/mainsheet rig that can hold the boom above centerline .. or maybe a preventer being rigged). Can't we deduce then that the general understood meaning of the BTL term requires the main to be filled from astern? (consistent with Call G1?). - Ang

Maybe better to boil it down to 4 simpler questions. Looking at the boat pictured below and assuming the main's position is being held by her running-rigging and that she is in a steady-state of sail (this isn't an instant in a transitional state) ..

1. Is the boat sailing "by the lee"? (why or why not)
2. Is the boat on port or starboard?
3. Does it matter at all which side her headsails (jib/spin/etc) is/are on?
4. Does Team Call G1 apply to Q's 1/2/3 (why or why not)?

By the Lee

Angelo Guarino

said Created: 18-Sep-21 16:38

Question: Does "Sailing-by-the-lee" require the mainsail to be "filled" a certain way, a certain side of the material, or filled all?

No, the definition of Leeward and Windward, which is the only place in the RRS which refers to ‘by the lee’ refers to which side the mainsail ‘lies’: it makes no reference to whether or not the sail is filled.

Main sail filled is introduced in the MR changes to rule 13 (rule C2.6), in defining the ‘while gybing’ condition, when a boat must keep clear

But I’m wondering what is the point of the question? In what realistic scenario is a more precise textual definition needed?

See the discussion at the foot of this post.

Angelo Guarino

said Created: 18-Sep-21 17:57

Yea, I'd seen that one [Team Race Call G1] Steve. One can imply an answer to my Question by that Call, but it doesn't actually come out and say that to be B-T-L it has to be filled one side or the other.

The TR Call G1, illustration 3 shows the boom to starboard of the centreline, and the description of Question 3 says that the wind is hitting the port side of the sail: by inference, then, the sail must necessarily ‘lie’ on the starboard side. I don’t see anything problematic with that

So, take their Question #3 and imagine a boat with their traveller full to one side and sheet tight such that the boom's end is over the port transom corner and the wind is coming over that same corner. With a flick the main is filled on one side of the material or the other, but the boom does not change position significantly .. so she's flipping from port to starboard based on that call even though she is sailing deep downwind and her boom stays on the port side of the boat.

Well, starting point is the boat was on starboard tack, directly downwind or by the lee, and the traveller and sheet are put in the position as described:

• If it’s a very flat main and a very wide traveller:
  • when the main fills with the wind on its starboard side, less than half of the sail will ‘lie’ on port side of the centreline, so the sail is ‘lies’ on the starboard side and the boat will be on port tack;
  • when the wind angle changes so that the main fills with the wind on its port side, then the boat will very definitely be on port tack
• If the main is somewhat fuller:
  • when it fills with the wind on its starboard side, the head and more than half of the sail will lie on the port side of the centreline and the boat will be on starboard tack;
  • when the sail fills with the wind on its starboard side, the boat will be on starboard tack.

Simon Winn

said Created: 18-Sep-21 21:35

Hi Guys

Look at definitions 'Leeward and windward' and 'Tack'..
If her boom was over the port quarter even tho'sailing by the lee the port side is her leeward side.

The word ‘boom’ does not appear anywhere in those definitions.

Angelo Guarino

said Created: 18-Sep-22 12:43

How about this as a general understanding of the term as further refined by the Team Call G1. It was an interesting challenge to find a concise way of describing how the mainsail needs to be filled. Anyone else have a clever or better way of describing how the main needs to be filled? I was tempted to use the term/concept of "backwinded" but interestingly that word depends upon the notion of the sail being in a normal position and then filling it on the "wrong side".

Sailing By The Lee: Sailing such that the wind is on the same side of the boat as the mainsail is carried and the wind is filling the mainsail into its aft-facing surface.lies or would lie if not artificially constrained

Warren Nethercote

said Created: 18-Sep-24 19:08

Angelo, do not fall into the trap of making it too complicated. :-)

The definition Leeward and Windward talks about 'the side on which her mainsail lies.' It you have to hold it there, or the sail is inverted, is it 'lying' there?inverted is not a good test: see MR UM E4 There is some real world wooliness when you have a crew member restraining the boom against an accidental gybe, but it is better to be comfortable with some ambiguity than struggle to find an unachievable perfect solution.

Strongly agree

Angelo Guarino

said Created: 18-Sep-25 03:12

Hey Warren ..interesting. So just to be clear, I wasn't suggesting adding a BTL definition to the RRS ... just trying to understand what BTL is understood to mean as implied by Q2 in Team Call G1.

In Question/Answer #2 in the Call G1 they state:

"Port tack. She is now neither running directly downwind nor sailing by the lee."

Why isn't she sailing BTL?

Because” the crew is is holding it there while the wind is backing her mainsail”

That is, the mainsail would lie on the other side if it was not ‘artificially constrained’

Now, if this was, say, a Laser and the mainsail was forward, not hand-held and filling, the boat would equally clearly be sailing by the lee on starboard.

Seems to me the only thing that changed about the main is the side it is filled. (I think we can take the crew-holding the main out of the question as we can think of a traveler/mainsheet rig that can hold the boom above centreline .. or maybe a preventer being rigged)

As illustrated in the call, the boom is not merely ‘above centreline’: it’s way outside the boat: a preventer, or a boom to toerail vang tackle might achieve that, or maybe a full width trav on a multihull, but not any normal traveller on a mono.

Can't we deduce then that the general understood meaning of the BTL term requires the main to be filled from astern? (consistent with Call G1?)

I’d be more inclined to say that it requires that the main not be ‘artifically constrained’: amplify that term as you will.

Angelo Guarino

said Created: 18-Sep-26 17:47

Maybe better to boil it down to 4 simpler questions. Looking at the boat pictured below and assuming the main's position is being held by her running-rigging and that she is in a steady-state of sail (this isn't an instant in a transitional state) ..

1. Is the boat sailing "by the lee"? (why or why not)
2. Is the boat on port or starboard?
3. Does it matter at all which side her headsails (jib/spin/etc) is/are on?
4. Does Team Call G1 apply to Q's 1/2/3 (why or why not)?

Created: 18-Sep-26 17:47

This can, and should be resolved by observing the boat and applying the definitions.

Hypothetically, if this was, say, a Laser with the boom out, we would have no hesitation in saying she was sailing by the lee on port tack.

As illustrated, the sail lies on the boat’s starboard side (rule a line from the luff of the sail to the middle of the transom if you doubt this). The sail lies to starboard, no less than it would if the boom was fully out on starboard. The boat is on port tack.

If the boom/traveller was a little further down and the sail a little fuller, the sail would ‘lie’ to port of the centreline, on the port side of the boat and the boat would be on the starboard tack.

Let’s consider a boat not so pronouncedly shy.

Between small changes in course, rolling and effect of gravity on the sails and small oscillations in wind, the mainsail of a boat, sheeted to the centreline, may ‘flop’ from side to side of the centreline, and thus the boat may change tacks and transition from right-of-way (ROW) boat to Keep Clear (KC) boat repeatedly and quite quickly.

When she ‘flops’ onto starboard tack, she may acquire ROW, not through any other boat’s action, and thus will be required to give a KC boat room to keepclear under rule 15.

When she ‘flops’ onto port tack, she may be required to keep clear of another boat, which will acquire ROW because of the gybing boat’s actions and thus will NOT be required to give any room to KC under rule 15.

Thus the boat, which is artificially pinning her boom in will flip-flop between ROW required to give room and KC boat: it’s all on her.

John (btw, the pic you tried to post didn't take .. you can edit your post and right-click on the image and try to repost),

Main sail filled is introduced in the MR changes to rule 13 (rule ), in defining the ‘while gybing’ condition, when a boat must keep clear

Nice reference. Actually I think it addresses the real-world situation in which this would typically arise .. 2 boats DW closely overlapped on port with W being controlled by L and W pulling her boom across center to the windward port side and calling starboard and keeping L on that line. With C2.6, that wouldn't work unless they had the room and ability to get it filled on the other side.

Curious, why do you think (or what argument is made) that rule isn't part of fleet racing RRS?

Sailing By The Lee: Sailing such that the wind is on the same side of the boat as the mainsail is carried and the wind is filling the mainsail into its aft-facing surface.lies or would lie if not artificially constrained

OK .. trying to work with that it begs the question of what "artificially constrained" means in the context that the RRS's allow for the hand-holding of sheets. Also, I like your thoughts on "lies" too .. I was starting to work toward a similar but slightly different take.

I was starting to work on the argument (was never convinced of it myself mind you) that, when a sail is shaped from the wind, that a sail "lies" away from that wind, regardless of where her boom is and thus a sail lies on the side of the boat that her leeward-side faces when wind-filled. The obvious problem with that is that advanced sails, windsurfing sails, and now fixed-wing sails can be/are fully and actively cambered so that falls apart quickly.

See Warren's post about 'lies'. A boat's sail, particularly in very light conditions, can 'lie' on a particular side, hanging down like washing on a line, without being 'filled' (in MR racing would be abandoned in those conditions because boats are unable to perform normal racing manoeuvres).

Keep clear while gybing was taken out of the rules in the 1995 rewrite, I'm guessing (because the only reference I have is Elvstrom, 1997, which doesn't even mention it) because it was appreciated that downwind gybing, with drive in the sails, was instantaneous and could be performed with no or little change in course, in contrast to tacking which inevitably involved substantial deceleration while passing head to wind, and a large change in course. If gybing was conceptually instantaneous, then you didn't want the complication of a sail in the process of filling. Whether a sail is filled or not is almost impossible to determine in a post-hoc protest hearing, while it is quite easy for umpires to observe.

Does this idea help? You can't gybe your sail into a by the lee situation, you can only gybe the boat.

So, looking at Angelo's Yellow boat diagram, if the boat started off on that course on starboard tack, and moved the main into the position shown on the starboard side, that's 'artificial'. See Match Race Call G5 and Team Race Call G1 Question 2.

OTOH, if she started out port tack and bore away and passed stern to wind (or the wind shifted), then there is no 'artificial constraing'.

But I still don't see how having a refined textual definition of 'by the lee' helps in the side by side downwind situation.

If W gybes onto starboard, gains right of way, she is required initially to give L room to keep clear

If there is any doubt about the precise instant that W has changed tack (say, relative the the instant that L takes action allegedly to avoid W, while W was still a give way boat), then last point of certainty was that she hadn't changed tack and was still give way windward boat.

Maybe we can consider two 'by the lee' classes:

1. 'slightly' by the lee, where 'sailing by the lee or directly downwind' may be indistinguishable and it is difficulty or impossible to tell which 'side' of the boat is leeward and which is windward by the 'side away from the wind' test in the Definition of Leeward and Windward; and
2. 'very' by the lee, where there is readily identifiable 'side away from the wind', which is trumped by the side on which the mainsail lies.

Class 1 'slightly' by the lee is what the Definition is designed for, and will apply nearly all the time in boats with stayed masts

Class 2 'very' by the lee, only really works with boats like the Laser, where the boom can be rotated very far out, and reverse flow over the sail achieved.

John, MR Call 5 is a great addition to the discussion! Good one. It addresses the exact concern I had (pulling the main "artificially" to the windward side).

"Answer 1a No. Yellow’s windward side does not change. She never sails by the lee and at no time would her mainsail lie on her starboard side if unrestrained.

But also the wording of MR Call 5 itself .. which specifically talks about the filling of sails

"A boat sailing downwind changes tack when she gybes and her sail fills on the new side and lies there if unrestrained."

... so the converse would be true . .'a boat does not change tack until she gybes and her sail fills on the new side and lies there unrestrained.'

So, our normal Laser sailing downwind, carving the waves, sailing back and forth under her main filled on one side, sails by the lee and not and doesn't change tack.because .her sail never .. " ... fills on the new side and lies there if unrestrained"

"lies there if unrestrained" seems to be getting at your "artificially constrained" idea. I notice that they aren't characterizing what could be restraining the sail .. no sense of "artificiallity" .... so I'm reading that as "if you let the sheets go .. now, on what side of boat does the sail lie?"

Interesting. Ang

I don't know where Paul got that headnote from. It's not in the Call Book. Nowhere in the Questions and Answers to MR Call G5 is there any reference to the sail being filled.

As I said before, a boat's mainsail can 'lie' on one side or the other without being 'filled'. The Definition of Leeward and Windward refers to 'lies' and does not mention 'filled'.

Perhaps the 'headnote' could be better worded

"A boat sailing downwind changes tack when she gybes her main sail crosses her centreline and her sail fills lies on the new side and would continue to lies there if unrestrained."

The Laser does not change tack because the side upon which her sail lies never changes. 'Fill' is no part of the definition.

I'm happy that 'lies there if unrestrained' means the same thing as I intended to mean by 'lies there if not artificially constrained'.

MR Call G5 certainly does characterise what would be '[artificially] restraining the sail' But I quite like the "if you let the sheets go .. now, on what side of boat does the sail lie?" test

But I quite like the "if you let the sheets go .. now, on what side of boat does the sail lie?" test

Me too. It's something simple, easy to explain, easy to remember, and fits common sense to boot .... and I think it covers most situations that we've both covered/invented, even when the sail is "hanging down like washing on a line" ..the test works there too as it will just hang there where you put it last and if those are the conditions, that seems just fine.

Think I'll hang my hat on that one until something knocks it off the hook. Nice exploration, John. Thanks - Ang