I couldn't get my GT11 to find any satellite signals this afternoon. Weird. It worked fine two days ago.
Today, it turned on OK, displaying the "Card Found" message.
After a period of time, displayed "Indoors? Yes/No". Responded "No" - was at edge of Lake Burley Griffin.
After a further period of time, displayed "Travel long? Yes/No". Responded "No" - I was at exact same place I last used it.
After about 5 minutes of no apparent progress, I turned it off, then on again. Same sequence of dialogues; this time I watched the screen showing satellite signal strength. Was void of any signals.

I tried the GT11 at home tonight; took ages to start, but seems OK now. That was a relief.
I don't think it could be an undervolt problem; I charged it up after Wednesday's sail.
Has anyone else experienced a transient "no signal" situation? Is there any logical explanation as to why it occurred? Is it a sign of impending complete failure of the GT11.
Prior to this, the device has performed flawlessly. I can't complain; I have certainly had my money's worth from it. I am not sure that I can now trust it as much as I used to.