New Posts New Posts RSS Feed: Keep Clear boat question
  FAQ FAQ  Forum Search   Register Register  Login Login

Keep Clear boat question

 Post Reply Post Reply Page  <1 4567>
Author
JimC View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 17 May 04
Location: United Kingdom
Online Status: Offline
Posts: 6260
Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 06 Sep 18 at 6:33pm
Originally posted by A2Z

 Why don’t the rules define the upwind boat as the windward boat?

I imagine because it makes other things more complicated. For example if you have two boats on a beat and the windward one is overlapping the leeward one by just a few inches the leeward boat is upwind of the windward one. Rule writing is an art of compromise: if you try to specify every bizarre situation that might occur then the rules end up unmanagably complicated.
Back to Top
Sam.Spoons View Drop Down
Really should get out more
Really should get out more


Joined: 07 Mar 12
Location: Manchester UK
Online Status: Offline
Posts: 2711
Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 06 Sep 18 at 7:48pm
Historically they have tried to do just that until the controversial revision which introduced the concept of room to keep clear (CBA looking up the date). Simplification, in this context, is very much relative.....
Spice 346 "Flat Broke"
Blaze 671 "supersonic soap dish"
Back to Top
Rupert View Drop Down
Really should get out more
Really should get out more


Joined: 11 Aug 04
Location: Whitefriars sc
Online Status: Offline
Posts: 8567
Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 06 Sep 18 at 8:24pm
My issue with all this is that, as the boat going upwind, how do you tell, especially is shifty conditions, whether the running boat is sailing by the lee? And if the wind shifts at a vital moment, the running boat suddenly finds they are no longer sailing by the lee?

Seems that not only is neither boat in the right, but the upwind boat has no chance of knowing when or whether they are the leeward boat, and the running boat can become windward boat through no action of their own at any time.

Firefly 2324, Lightning 130, Puffin 229, Minisail 3446
Back to Top
Sam.Spoons View Drop Down
Really should get out more
Really should get out more


Joined: 07 Mar 12
Location: Manchester UK
Online Status: Offline
Posts: 2711
Post Options Post Options   Quote Sam.Spoons Quote  Post ReplyReply Direct Link To This Post Posted: 06 Sep 18 at 8:36pm
By the lee is a red herring, according to the RRS, windward/leeward depends only on the attitude/position of the respective boats. The only thing that matters is that the running boat, Blue, is (in this scenario) to the right of dead ahead of the boat sailing upwind, Yellow, and thus is windward boat until it falls to the left of dead ahead (which involves crossing the path of Yellow).
Spice 346 "Flat Broke"
Blaze 671 "supersonic soap dish"
Back to Top
JimC View Drop Down
Really should get out more
Really should get out more
Avatar

Joined: 17 May 04
Location: United Kingdom
Online Status: Offline
Posts: 6260
Post Options Post Options   Quote JimC Quote  Post ReplyReply Direct Link To This Post Posted: 06 Sep 18 at 9:20pm
Originally posted by Rupert

My issue with all this is that,

No, its the other way round... If the definition was which side the wind was coming from instead of which side the sail was on, then you'd have to know whether the boat was running by the lee or not. As it is you only have to look at the sail. Its just that the boats can only get in this position of boats on the same tack on a bow to bow collision course if one is sailing by the lee - or of course if you're on a Norfolk river and the wind is going round in circles...
Back to Top
Brass View Drop Down
Really should get out more
Really should get out more


Joined: 24 Mar 08
Location: Australia
Online Status: Offline
Posts: 982
Post Options Post Options   Quote Brass Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep 18 at 12:06am
Originally posted by Sam.Spoons

I blame Steve Cockrill, before his 4th Dimension nobody sailed by the lee  Angry

For those bothered about the effectiveness of the rules in this scenario, this explanation is spot on.

It is a situation that the original rules drafters just never envisaged.
Back to Top
Brass View Drop Down
Really should get out more
Really should get out more


Joined: 24 Mar 08
Location: Australia
Online Status: Offline
Posts: 982
Post Options Post Options   Quote Brass Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep 18 at 12:14am
Originally posted by mozzy

Originally posted by Brass

You might like to try reworking the problem with Y a little to the right and B a little to the left, so that they are passing port to port, and see what you get.

 
Like this ^?

Yes

Both on starboard. 

Yes

Overlapped as neither is clear astern.

Yes

Both are on the leeward side of the other at position 2, therefore both are leeward boats, but then both are also leeward boats as they classify as the 'other' in the leeward and windward definition.

Now is the time to do the analysis from each boat's separate point of view.

From Red (R) pov, there is a boat Blue (B) on the same tack on her leeward side, that is B is a leeward boat, so R is a windward boat, and R, as windward boat, is required by rule 11 to keep clear of B, and B is a right-of-way boat.

Note that being right-of-way boat is significant for rules 15 and 16, but it would be circular to say that a boat is required to be kept clear of because she is a right-of-way boat:  other way round:  she is a right-of-way boat because she is required to be kept clear of.

From B pov there is a boat, R on the same tack on her leeward side, that is R is a leeward boat, so B is a windward boat, and B as windward boat is required by rule 11 to keep clear of R an R is a right-of-way boat.

But the only one can be leeward

Nope.  No rule or definition says this.  They look like they should be mutually exclusive, but applying the definitions as we have done, demonstrates that they are not.

 and the other de-facto windward if one is leeward. 

mmm confused again now, can both be keep clear boat and right of way boat at the same time??

Because that's how the definitions, logically applied work out in this anomalous scenario.

Possibly the answer is that at position 1, red is on the leeward side of blue, therefore blue is the windward

This is getting interesting.

@1, I would suggest that the boats are so far apart that it is not possible to say that one is 'on the leeward side of the other.  This issue is similar to several cases or appeals where it is said that it is not possible to say which boat, of two coming in different directions, is inside, and which outside near a mark

At some later point, not later than when a line abeam (at right angles to the boat's centreline) of one boat's stemhead intersects the other boat (that is, what we would more intuitively recognise as 'overlapped'), 'on the leeward side' will assume a clear meaning and rule 11 will apply.

 and keep clear boat under rule 11. So pretty clear cut at that point.

So I don't think right of way is clear cut @1:  boats are more than 5 lengths apart:  it's not an issue.

The difficulty would be telling the exact point when blue passed in front of red, going on to the leeward side of red, so both boats can be defined as leeward boats. 

Quite possibly, given that B, surfing downwind will be jinking around all over the place.

Originally posted by Sam.Spoons

As neither one is 'to windward' of the other neither can be give way boat so back to rule 14

Originally posted by Sam.Spoons

At pos 1 Blue is to windward of Red so must be keep clear boat (as would be the case in the original situation, if Blue was not sailing by the lee Yellow would be leeward boat and have RoW. 

Sam, the difficulty with this analysis is that the rules don't use the term 'to windward':  they define leeward side and windward side and and go on to define leeward boat and windward boat by the attribute 'being on the leeward side'

@1, see the analysis above in response to Mozzy:  being upwind does not make B a windward boat according to the definition.
Back to Top
Rupert View Drop Down
Really should get out more
Really should get out more


Joined: 11 Aug 04
Location: Whitefriars sc
Online Status: Offline
Posts: 8567
Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep 18 at 6:56am
So, if this went to protest, how many club protest committees would look at it and bin the upwind boat?

The point I was failing to make earlier wasn't to do with sailing by the lee, but of the difficulty boats closing on each other would have in calculating that the boat upwind wasn't the boat to windward, so making this a virtually impossible situation to spot, especially in a mixed fleet. I'm sure Laser sailors are getting used to such situations??

And that the upwind boat can become windward boat with a very small change of wind direction. Though this one makes my head hurt.
Firefly 2324, Lightning 130, Puffin 229, Minisail 3446
Back to Top
andymck View Drop Down
Far too distracted from work
Far too distracted from work


Joined: 15 Dec 06
Location: Stamford
Online Status: Offline
Posts: 367
Post Options Post Options   Quote andymck Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep 18 at 8:11am
For both scenarios
 Why is this not rule 15?
The blue boat acquires a technical right of way between position 1 and 2. With the closing speed, this is likely to very close to the time that one of them would need to start keeping clear. 

We would also probably resort back to the last point of certainty in a protest meeting?

This is perfectly plausible in a 2 sail boat, I regularly used to sail by the lee in my N12. Very quick.

Andy


Edited by andymck - 07 Sep 18 at 8:15am
Andy Mck
Back to Top
Guests View Drop Down
Guest Group
Guest Group
Post Options Post Options   Quote Guests Quote  Post ReplyReply Direct Link To This Post Posted: 07 Sep 18 at 8:47am
Originally posted by Brass

 
Now is the time to do the analysis from each boat's separate point of view.

From Red (R) pov, there is a boat Blue (B) on the same tack on her leeward side, that is B is a leeward boat, so R is a windward boat, and R, as windward boat, is required by rule 11 to keep clear of B, and B is a right-of-way boat.
This is where I'm still a bit lost. Surely from red's point of view, they look at Blue and think, I am on their leeward side, therefore I am a leeward boat. Therefore Blue is windward boat and keep clear under rule 11. Therefore I am right of way. I don't see what in the definition leads red to interpret it the other way around. If anything the definition invites you to consider yourself as the 'one' leeward boat first, rather that the 'other', which later de-facto becomes windward.  


Originally posted by Brass

 
Note that being right-of-way boat is significant for rules 15 and 16, but it would be circular to say that a boat is required to be kept clear of because she is a right-of-way boat:  other way round:  she is a right-of-way boat because she is required to be kept clear of.
I still don't feel that. The preamble to section a states "A boat has right of way over another boat when the other boat is required to keep clear of her.". It certainly feels pretty circular. Are you saying that it's okay for a boat to be both keep clear and right of way and she is only right of way because some else is keeping clear of her? 

How does the definition of the keep clear then work? You must allow a right of way boat to sail her course, so the first person who alters their course to avoid the other is no longer sailing their course. Does that mean the other has broken the rule to keep clear? 

Originally posted by Brass

 
From B pov there is a boat, R on the same tack on her leeward side, that is R is a leeward boat, so B is a windward boat, and B as windward boat is required by rule 11 to keep clear of R an R is a right-of-way boat.
Firstly I'm unsure what in the rule or definition would lead each boat to conclude they were windward boat over leeward boat. But secondly, it does seem you are saying both are keep clear boats in their own heads, but that also makes each other right of way boats. If it doesn't make the other boat also a right of way boat, then they don't need to keep clear, because the definition of keep clear only obliges you to keep clear of a right of way boat. 

Perhaps both can act as if they are keep clear boat, considering the other to be right of way boat. But it is important to know you are right of way boat too, as that places some restrictions on how you can manoeuvre. 
Originally posted by Brass

 
Originally posted by Mozzy

 
But the only one can be leeward 
[QUOTE=Brass] 
Nope.  No rule or definition says this.  They look like they should be mutually exclusive, but applying the definitions as we have done, demonstrates that they are not.

 and the other de-facto windward if one is leeward. 

mmm confused again now, can both be keep clear boat and right of way boat at the same time??

Because that's how the definitions, logically applied work out in this anomalous scenario.

When we applied the definitions before, we concluded if there is not one leeward boat, then there can't be a windward boat. Therefore there are no windward boats. 

"When two boats on the same tack overlap, the one on the leeward side of the other is the leeward boat. The other is the windward boat."

However, in this case we have more than one leeward boat. Which doesn't seem to be a situation catered for in the definition. The definition could state "a boat on the leeward side of another is the leeward boat". That would allow both boat to be leeward boat. But the definition clearly states one is the leeward boat and the other is windward. That certainly seem to clearly say a situation can't exist where there are two boats and both are leeward. 



Edited by mozzy - 07 Sep 18 at 8:52am
Back to Top
 Post Reply Post Reply Page  <1 4567>

Forum Jump Forum Permissions View Drop Down

Bulletin Board Software by Web Wiz Forums® version 9.665y
Copyright ©2001-2010 Web Wiz
Change your personal settings, or read our privacy policy