What's going on here?

[Stingo]

I'm stalking a friend, via Iridium tracking, who is crossing the South Pacific at the moment. Any guesses what's happened that caused the two downwind zigzags, circled in this screenshot?

My guess is the autopilot gave them a middle finger, but in my humble opinion, that wouldn't result in a course change to leeward.

I don't know the answer, yet. I've sent the screenshot to him asking what happened. I'm sure he'll reply once he has wifi again and once he's swallowed a few beers.

 

[KevinV]

Hove to?

 

[Stingo]

Hove to?

Ah, could be! That makes sense, all in the interests of arriving while the sun is still shining, especially in that part of the world where the charts are known to have huge errors.

 

[AndrewB]

Hove to or making sail changes to slow down? That looks like he is approaching the Tuamotu Islands. If so timing is everything to get into some of the lagoons, you need to arrive in daylight at just the right stage of the tide, specially if the wind is strong.

 

[Stingo]

Good points, but he's on a monomaran, so sail changes would be into wind.
See #3 ref timing your arrival.

 

[sarabande]

edges of time zones ?

 

[B27]

Could be avoiding other craft?
It would be easier to guess if you knew speeds or times on that course.

I tend to be sceptical of the wind directions shown on these apps after my mate's boat was tracked going dead up wind for a few hours during the Fastnet race. So it could be tacks or gybes.

 

[Stingo]

edges of time zones ?

At approx 145° W, they're still 35° east of anything as confusing as crossing the dateline.

 

[Stingo]

My money is on @AndrewB's suggestion in #4

 

[dunedin]

Good points, but he's on a monomaran, so sail changes would be into wind.
See #3 ref timing your arrival.

Best practice for furling a roller genoa is to bear off

 

[Mister E]

In the bog having a big dump.

 

[Pete7]

He has been watching Red October on DVD and now throwing in some 'crazy ivans'.

 

[Supertramp]

Might be an anomaly in how the system is plotting his track - I have seen "jumps" in mine and put it down to some sort of defect in my tablet like losing GPS signal for a bit and then filling in the spaces.

 

[Sea Change]

How long is each 'jump'? Could just be a glitch in the tracking. You see this with flight radar.

 

[claymore]

Stinko - could it be that the friend is engaged in slipping the crew a crippler?