La Vagabonde's crossing

[Breaking Waves]

just keeping an eye on the early December developments - which we have agreed above are a bit messy and not settled (forecast wise).

This is a picture for dec 4th, with euro model on left and gfs on right, is about the point of maximal divergence between the two. two major differences I have circled - Euro has a relevant low off morocco which gfs does not have, and gfs has low far enough west in med that it could start to be relevant (squeezing the big high further offshore) which euro has rather further east.



GFS picture would be a relatively pleasant finish for LV, especially with a routing coming in a bit from the north. The Euro model has the wind more easterly and with greater energy scattered around, still np but absolutely needs to set up approach from northerly.

For routing purposes, I would set-up to make sure we are covered for the euro scenario both because euro model is likely to more correct, and because setting up for it also covers the gfs scenario.

This is some distance out in the forecast timeframe and divergence is not unexpected. just keep track of it, and make sure to take a close look around 28th mid-night when deciding whether to turn more north or not.

[boatman61]

Originally Posted by Cherod

oh errr ,, i thot that my question was obviously facetious ,, thank you for that rather stating the obvious reply anyway ..
personally i have no desire to go to sea alone and love having passengers on board , sometimes a lot easier than a bunch of know alls .

Yeah.. I guess the thought of dying alone does scare some folks..

[Cherod]

Originally Posted by boatman61

Yeah.. I guess the thought of dying alone does scare some folks..

well i guess you are no alone in that ,, but sometimes probablly the better option

[OldKetch]

Originally Posted by Breaking Waves

just keeping an eye on the early December developments - which we have agreed above are a bit messy and not settled (forecast wise).

This is a picture for dec 4th, with euro model on left and gfs on right, is about the point of maximal divergence between the two. two major differences I have circled - Euro has a relevant low off morocco which gfs does not have, and gfs has low far enough west in med that it could start to be relevant (squeezing the big high further offshore) which euro has rather further east.

This is very interesting. There appears to be a divergence also between the same model from different sources. The picture below is from the PW website, and supposed to be the same as above. Noon on 4 Dec, left is ECMWF, right is GFS. Especially the low off Morocco is missing, but there are some additional potentially sensitive differences.

[Cherod]

latest position still heading NE ( 68 deg ) about as much N as i would think winds permitting , perhaps getting as far up as poss so the last beat will be as much on the beam as possible .

[smj]

Originally Posted by HeinSdL

(and her opinion). Indeed, but normally one keeps it to oneself if it deviates too far from the norms dictated by common decency and respect for your fellow human being.

And I guess it all depends on one’s definition of common decency and respect.
There have been plenty of times that I have posted on this forum then later regretted what I had posted, and many times I’ve apologized for that. We are all human.

[Cherod]

by definition " common " decency is not defined by "ones " definition of it but by a commonly accepted standard which we all respect and abide by ,, unless one is a total jerk ( which in this instance may well be the case ) .

[boatman61]

Originally Posted by Cherod

well i guess you are no alone in that ,, but sometimes probablly the better option

Good reason for solo.

[smj]

Originally Posted by Cherod

by definition " common " decency is not defined by "ones " definition of it but by a commonly accepted standard which we all respect and abide by ,, unless one is a total jerk ( which in this instance may well be the case ) .

I live by my definition and you can live by whatever you feel fit, which I may not respect and abide by.

[Breaking Waves]

lastest model run consistent with this morning - suggests

climbing NE for another 6 hrs (but they are sailing faster atm than polar predicts)
and then roughly due east a further 16 hrs - 25 ish kts sustained probably gusty
and then re-evaluate final weather pattern

roughly dec 6th eta



and guys . . . . really?

[Discovery 15797]

Originally Posted by funjohnson

And I hate sailing with crew. I do not want anyone besides my wife in my space for that length of time.

Matt

If you are insecure it's best you don't sail with crew.

[ccannan]

Originally Posted by Auspicious

It's pretty easy to run the numbers for horizon to horizon time for commercial traffic on a reciprocal course. For the amount of sleeping you did--not enough to really get rested--you could well have missed traffic. I see much more traffic than you report.

Of course, I could be wrong, but I don't think I missed any vessels that entered my visual horizon.

A statement I made in a previous post was in error. I should have stated that I didn't schedule any of my naps to be shorter than 20 minutes, and never slept more than 40 minutes during my transatlantic crossing. Many, many of my naps were shorter than 20 minutes because of radar alarms detecting vessels beyond my visual horizon. If asleep, I would wake up, get up, measure the range and calculate the CPA of any radar contacts. If I determined the vessel represented a potential conflict I would stay up and monitor until it no longer was. In cases of no conflict, since I was already up I'd scan the horizon again before starting another planned 20 minute sleep cycle (if I felt tired).

On flat water, during daylight hours, and no visual obscurations (rain, fog, mist), with an eyeball 10ft off the water, the visual horizon is just under 3.5nm. A radar mounted 25ft off the water has radar horizon just over 6nm. For most recreational sailboats the highest rate of closure between two recreational sailboats will probably not exceed 20kts (a more realistic rate of closure would probably be less than 14kts). Assuming the closing sailboat doesn't have a sail up (making it visible farther away) and has a freeboard of 4ft it would start to become visible to the other sailboat at a distance of just over 7nm. In 20 minutes the two boats will travel 6.6nm (at 20kts) or 4.7nm (at 14kts). There isn't much time (1 minute) to see and avoid at 20kts of closure, but would be more manageable (10 minutes) at 14kts of closure. IMO the chances of two sailboats closing at 20kts with their sails down, no AIS, and not being detected by radar is small (a radar return should start to become detectable at approximately 8.5nm). Merchant ships can and do travel at much higher speeds but also are much taller, have AIS, and larger radar signatures. A ship having a freeboard of 50ft will start to be visible at just under 11nm. Assuming a closure rate of 30kts (a more reasonable rate might be 25kts) the boats will travel 10nm (at 30kts) in 20 minutes. Again, not leaving much time (2 minutes) to see and avoid. However if the rate of closure is 25kts the distance traveled will be 8.3nm, giving more time (5.3 minutes) to see and avoid. Almost all transatlantic merchant vessels emit AIS signals, and a radar should be able to start to detect ships at just under 15nm.

I didn't have an AIS on that trip, but AIS offers even greater horizons.

[Pelagic]

Originally Posted by Breaking Waves

lastest model run consistent with this morning - suggests

climbing NE for another 6 hrs (but they are sailing faster atm than polar predicts)
and then roughly due east a further 16 hrs - 25 ish kts sustained probably gusty
and then re-evaluate final weather pattern

roughly dec 6th eta



and guys . . . . really?

Thanks Breaking Waves with staying on course with this fantastic exercise in modern weather routing.

I apologize for those on both sides who want to moralize rather than learn.....
Sometimes you can't choose your shipmates! [emoji20]

[smj]

Originally Posted by Discovery 15797

If you are insecure it's best you don't sail with crew.

I’m with funjohnson, my wife and I don’t need a bunch of people around to feel whole, sorry you don’t feel the same security.

[Dockhead]

Originally Posted by ccannan

Of course, I could be wrong, but I don't think I missed any vessels that entered my visual horizon.

A statement I made in a previous post was in error. I should have stated that I didn't schedule any of my naps to be shorter than 20 minutes, and never slept more than 40 minutes during my transatlantic crossing. Many, many of my naps were shorter than 20 minutes because of radar alarms detecting vessels beyond my visual horizon. If asleep, I would wake up, get up, measure the range and calculate the CPA of any radar contacts. If I determined the vessel represented a potential conflict I would stay up and monitor until it no longer was. In cases of no conflict, since I was already up I'd scan the horizon again before starting another planned 20 minute sleep cycle (if I felt tired).

On flat water, during daylight hours, and no visual obscurations (rain, fog, mist), with an eyeball 10ft off the water, the visual horizon is just under 3.5nm. A radar mounted 25ft off the water has radar horizon just over 6nm. For most recreational sailboats the highest rate of closure between two recreational sailboats will probably not exceed 20kts (a more realistic rate of closure would probably be less than 14kts). Assuming the closing sailboat doesn't have a sail up (making it visible farther away) and has a freeboard of 4ft it would start to become visible to the other sailboat at a distance of just over 7nm. In 20 minutes the two boats will travel 6.6nm (at 20kts) or 4.7nm (at 14kts). There isn't much time (1 minute) to see and avoid at 20kts of closure, but would be more manageable (10 minutes) at 14kts of closure. IMO the chances of two sailboats closing at 20kts with their sails down, no AIS, and not being detected by radar is small (a radar return should start to become detectable at approximately 8.5nm). Merchant ships can and do travel at much higher speeds but also are much taller, have AIS, and larger radar signatures. A ship having a freeboard of 50ft will start to be visible at just under 11nm. Assuming a closure rate of 30kts (a more reasonable rate might be 25kts) the boats will travel 10nm (at 30kts) in 20 minutes. Again, not leaving much time (2 minutes) to see and avoid. However if the rate of closure is 25kts the distance traveled will be 8.3nm, giving more time (5.3 minutes) to see and avoid. Almost all transatlantic merchant vessels emit AIS signals, and a radar should be able to start to detect ships at just under 15nm.

I didn't have an AIS on that trip, but AIS offers even greater horizons.

In my personal opinion, it is a fool's errand for a single hander to try to keep the visual watch at all times or minimize the lapses to 15 minutes or 30 minutes or whatever. It is realistically safer in my opinion to rely on your electronics and rely on the other vessel avoiding you, during periods of time sufficient for you to get a reasonable amount of sleep. AIS with a LOUD alarm and a good radar with double guard zones set is your best bet, but bearing in mind that this is not 100% foolproof and you are taking a certain risk.


Or alternatively heave to and show NUC signals, which is safest of all even if it violates COREGS.



But I am very skeptical, personally, that the every 15 minute horizon scan is worth the sleep deprivation it costs, and the degradation of alertness, except in areas of traffic, but you shouldn't sleep AT ALL in areas of traffic.