Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 13-11-2012, 13:38   #106
Registered User

Join Date: Jan 2012
Posts: 450
Re: VENDÉE GLOBE round the world race

We have a famous sailor here in france who said "when you don't know where to go, go West "
__________________

__________________
maitai is offline   Reply With Quote
Old 13-11-2012, 16:51   #107
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
Re: VENDÉE GLOBE round the world race

Quote:
Originally Posted by Lohi View Post
You know what they say, a smart person learns on other peoples mistakes and fool learns on his/hers own(i guess i know what bracket i fall into). The forecast was showing strong winds near the coast of Africa and i was assuming* i will be able to ride it all the way to Canaries. Well i will pay for that in the next couple of days.

* Assumption = Mother of all f...ups
Do not take it too hard. Today's forecast for tomorrow may change to your advantage tomorrow. It is only a forecast and it rolls every 12 hours or thereabouts.

On the water, if caught, one has to make the dramatic decision: to stick and wait for the next wx forecast or to cross the light zone and go into the pressure on the opposite side. Remember the real thing cannot use the motor ...

In the real race I think there is at least one boat that looks like wants to take on the low by sailing round its top. Meanwhile Riou gave up 10 positions or so to get into the pressure early. We will see tomorrow who was right and who... assumed ;-).

Cheers,
b.
__________________

__________________
barnakiel is offline   Reply With Quote
Old 13-11-2012, 17:21   #108
Registered User
 
rgleason's Avatar

Join Date: Mar 2012
Location: Boston, MA
Boat: 1981 Bristol 32 Sloop
Posts: 9,407
Re: VENDÉE GLOBE round the world race

Thank you Maitai and Barnakiel, I've been thinking about this little problem. As I go west I will lose VMG to the finish, and lose compared to those who have already made the move like Maitai, quite obviously. I decided to run a routing from near Maitai down to a fair distance below WP1 Gate and to the west, and then compare it to a routing I could take to the same location.

It's inconclusive, but looks fairly close on "paper", so to speak. There's a nice bump in wind speed in certain areas later on which is helpful, but at some point I'm going to have to cut West big time I think.

What I don't know would fill a library.

PS: This really instructive in looking at the Real Race and they're figuring this out while actually sailing the boat. Incredible.
__________________
rgleason is offline   Reply With Quote
Old 13-11-2012, 18:00   #109
Registered User
 
rgleason's Avatar

Join Date: Mar 2012
Location: Boston, MA
Boat: 1981 Bristol 32 Sloop
Posts: 9,407
Re: VENDÉE GLOBE round the world race

Now after some more routing tests, it looks like routing to the same point to the west and well south of WP1 Gate, leaves me behind by about 40 nm. The crossing to get there is somewhat bothersome.
__________________
rgleason is offline   Reply With Quote
Old 13-11-2012, 18:56   #110
Registered User
 
rgleason's Avatar

Join Date: Mar 2012
Location: Boston, MA
Boat: 1981 Bristol 32 Sloop
Posts: 9,407
Re: VENDÉE GLOBE round the world race

Maitai, my current routing takes me right over the top of Cape Blanc with the resultant fat red route marks. Will the routing strand me and result in a penalty of time? How do I avoid this?

Should I do another route with a blockade?

Maitai said in a Post here:
Quote:
You create 2 POIs (better to make them of a beacon type), right click on one of them, and draw a line (the last option)
__________________
rgleason is offline   Reply With Quote
Old 13-11-2012, 20:19   #111
Registered User
 
rgleason's Avatar

Join Date: Mar 2012
Location: Boston, MA
Boat: 1981 Bristol 32 Sloop
Posts: 9,407
Re: VENDÉE GLOBE round the world race

Yes, that worked, but would like to create a barrier with multiple points, even using couples of beacon points this is difficult.
__________________
rgleason is offline   Reply With Quote
Old 13-11-2012, 22:30   #112
Registered User

Join Date: Jan 2012
Posts: 450
Re: VENDÉE GLOBE round the world race

You can also study alternatives by putting some pivot points on the routing (right-click on a isochron point for that).
__________________
maitai is offline   Reply With Quote
Old 14-11-2012, 03:27   #113
Registered User
 
rgleason's Avatar

Join Date: Mar 2012
Location: Boston, MA
Boat: 1981 Bristol 32 Sloop
Posts: 9,407
Re: VENDÉE GLOBE round the world race

Yes Pivot Points are helpful, have not used them much. I was also thinking that barriers are also a good routing tool to guide the routing.

Maitai, what happens when your routing, converted to route and sent to the autopilot, has red collisions with land?

I suppose you could use pivot points to try avoiding the collision. Then if there is a second collision use a second pivot point. -Is that how you do it?

What is a reverse pivot good for?

Right now it appears you are about 150 miles ahead at a waypoint west towards brazil and well south of WP1 gate. I am presently in a 5 knot hole for the next 5 hours which was unexpected!
__________________
rgleason is offline   Reply With Quote
Old 14-11-2012, 03:41   #114
Registered User

Join Date: Jan 2012
Posts: 450
Re: VENDÉE GLOBE round the world race

The routing method for detecting coast collision is not as accurate as the one of the route module, because it would take too much time and cpu. Soonce converted in a route in some cases you have to move a bit the POI manually to fix it. It's quite rare though.

There is no something like "reverse pivot" what are you refering too?

You are indeed very close from the coast ...
__________________
maitai is offline   Reply With Quote
Old 14-11-2012, 03:48   #115
Senior Cruiser

Cruisers Forum Supporter

Join Date: Aug 2009
Location: between the devil and the deep blue sea
Boat: a sailing boat
Posts: 17,314
Re: VENDÉE GLOBE round the world race

Quote:
Originally Posted by rgleason View Post
(...) PS: This really instructive in looking at the Real Race and they're figuring this out while actually sailing the boat. Incredible.
They are playing alternative routes then making decisions based on local conditions (which can vary dramatically from what the grib says). Even though, I can tell you first hand at times it IS a game of poker.

b.
__________________
barnakiel is offline   Reply With Quote
Old 14-11-2012, 11:47   #116
Registered User
 
hwecken's Avatar

Join Date: Feb 2012
Location: Germany
Boat: HR382
Posts: 110
Hi Rick
at the moment we have no chance to head west.
I think the earliest try to go west is around the area of Cap Verde.
And then it is like poker to pass the ITC on the shortest way to reach the SE trades
This year it can pay off to go along the african coast and with every grib change it looks better
Hartmut, SY Kirke
__________________
hwecken is offline   Reply With Quote
Old 14-11-2012, 18:59   #117
Registered User
 
rgleason's Avatar

Join Date: Mar 2012
Location: Boston, MA
Boat: 1981 Bristol 32 Sloop
Posts: 9,407
Re: VENDÉE GLOBE round the world race

Hartmut,

That is encouraging. I have both routes before me. One moving west at Cape Blanc and one following the coast. I have reasonable confidence about the winds in the South Atlantic for the longer windier western route, and it is less clear what conditions will be under the back of Africa's head. I have the luxury of following you, but with a hole just behind me I am trying to get well out of.

Maitai,

Thank you for the information on collisions. I currently have about 6 blockades, but it appears some of these problems are fixed when optimizing Routes, and finally you advise that we can change a couple of way points. If a route shows red, can we hit the land without worry, or are we penalized? Does the boat just keep going or does it get stuck or stranded?

Also on one headland I put a barricade off the coast a slight bit, the routing took a course going just inside the barricade and back out,without hitting land. That section of routing was shown in Bold Red. How is that type of crossing treated?

Earlier I meant "Create a pivot editing routing options"... I am just going to have to try it.

Finally, Maitai, you should know that without qtVLM software the boat rgleason would not be where it is! Its been fun learning its power , despite the . See you're then one responsible . Fortunately my wife is interested and has asked where the boat is.

Best
Rick
__________________
rgleason is offline   Reply With Quote
Old 14-11-2012, 22:46   #118
Registered User

Join Date: Jan 2012
Posts: 450
Re: VENDÉE GLOBE round the world race

Hello Rick,

Good to see you have fun

In VLM if you crash on land there is a "stop-and-go" penalty. In this race it's 15 min. So you cannot move during 15 min (you can send orders to your boat but it wont move for 15 min). After this time, if you didn't send any order to your boat, the boat is set by VLM on TWA mode, at 0 degree, so it won't move either until you do something. So better avoid that...

I don't quite understand your problems with routing and coast collision... Normally there is no need now to put barriers and qtVLM should do the job. Did you change any options? btw there is a nice button in advanced routing setting to restore the default ones...). Can you post a screen shot of a failed routing (without barriers)?

Fair winds to all.
__________________
maitai is offline   Reply With Quote
Old 15-11-2012, 07:12   #119
Registered User
 
rgleason's Avatar

Join Date: Mar 2012
Location: Boston, MA
Boat: 1981 Bristol 32 Sloop
Posts: 9,407
Re: VENDÉE GLOBE round the world race

Maitai, here's a couple of screen shots.

First one shows routing from your and my current position to a point west Lat -12, Long -22, showing rgleason behind by the180nm + 10:30 hours difference. There's a routing that goes east from my position that does not look too bad, but its too early to tell what will happen after that. Hartmut, Kirke is doing well and has lengthened lead with respect to me and my neighbors to about 64nm. In about 1-2 hours we'll have better winds

Second one shows boat routing bouncing off Cape Blanc coast and a series of blockades or Barriers. The yellow routing is not showing collisions, although it does show a routing with tacks inside of the blockades. Earlier these tacks would sometimes show up in bold read as hitting land, stranded (15 min. penalty - thanks for detailed explanation of what happens). I have most Options on the default settings (inet proxy, units, graphics set, Planishere, Language-Eng). Under Boat -Roaming Calculation # Cranks is 25 right now. Confirm each order to VLM is checked. This # of cranks might be the thing that is causing it. Perhaps near a coast the Boat # cranks should be smaller?

Looks like you guys are hauling south fast.

Rick
Attached Thumbnails
Click image for larger version

Name:	Vendee-CapeBlanc-Alternatives.png
Views:	70
Size:	376.8 KB
ID:	49744   Click image for larger version

Name:	Vendee-Barriers-CapeBlanc.png
Views:	68
Size:	372.7 KB
ID:	49745  

__________________
rgleason is offline   Reply With Quote
Old 15-11-2012, 07:52   #120
Registered User

Join Date: Jan 2012
Posts: 450
Re: VENDÉE GLOBE round the world race

Rick,

The Route module does not see barriers. Only Routing does.

Moreover, the route's simplification/optimization does not take coasts on consideration. When converting a routing in a route, the routing modules flags some POIs as "not simplifiable" but still it might happen that the simplification/optimization process remove or move a POI that was important to avoid coast or barrier. We have decided to leave it like that because detecting coast takes a lot of ressource and time and it was a pain when running this.

Normally, if you convert a routing in route it must be very rare that the route crosses coasts or barriers, if you don't simplify or optimize it.
__________________

__________________
maitai is offline   Reply With Quote
Reply

Tags
race

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 02:00.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.