Zezo forum:

Post by WretchedExess | 2018-02-10 | 21:33:04

Last night I had to set program points to pass through Okinawa. On top of a bunch islands being in the way, there was a big wind shift to take into consideration. I spent the better part of an hour laying out 3 points to get me through this mess. I even took screen shots to document what I had done.

All this was to know avail. I woke up at 04:00 and checked my phone. Sure enough there was the notification that I had been aground for three and a half hours. DAMN IT! I ran aground on Iwo Tori Island. I was careful to zoom to the maximum level of any land I was going to be close to, and set my course.
Question 1
What is the rule of thumb for the amount of distance to give a land mass?
Question 2
When setting program points, Does VR take in to account future weather when showing your course over a period of hours.

As a side note I was using locked TWA at the time.

6 Comments

Post by natto | 2018-02-10 | 22:49:21

I think most on this forum will recommend that you use waypoints for navigating in close proximity to land, especially when you you are programming your course more than a short time in to the future. It sounds like what happened is that the actual game wind varied enough from the forecast that your actual course changed due to fixed TWA. Sorry you had to learn this the hard way!
-Nat

Post by BGSteMarine | 2018-02-11 | 00:53:07

Hi WretchedExess,
from my understanding, the answer to your question 2 is yes. Future weather is taken into account when showing your course over a period of hours. But it is shown with the forecast which is current at the time you look at your future track, and therefore it can change when this forecast change itself, which happens 4 time a day.
When we look at your trace, we can see that there has been an inflection of your trajectory to the north with the new forecast of 06:00 UTC, and this makes you aground in the island ...
I have been quite close to have the same problem, but have had the chance to correct it before it happens, and from what i have seen in the forum, it sounds several skippers have had the same problem too.
We clearly have to be very cautious with program points when there is a change of forecast during the period !
-bg

Post by WretchedExess | 2018-02-11 | 03:33:43

I can understand if the forecast changes, and I thought about that. I knew there was going to be an up date at 01:00 EST. but I went aground 30 minutes before that. I'll have to be more careful in the future.

Post by DeepBrine | 2018-02-11 | 04:28:17

I think the forecast comes on as a gradual transition, not a step change but don't take my word for that. I think that is more for someone like Czetan to answer. I just don't recall seeing sharp transitions like we used to in previous years.

Post by zezo | 2018-02-11 | 08:46:07

During the 3-hour transition period between the old and new GRIB the game client and server may not be in sync, and then the client lies to you about the numbers - you can see one set on screen and another in server data. Sailing fixed TWA in certain direction makes the numbers add to 360, but the server may report different direction if obeying the TWA.

For a long run with programmed turns using TWA i'd leave at least 2-3 degree margin to the rocks. Also observe how the programmed track changes over at least a half hour.