I'm telling a short tale to purge my regretful feelings and possibly be informative:
Today is the last day of a local weekend estate sale that features among other things a late 19th century John Poole maritime chronometer. Spotlighted when you walked in the door, it was nevertheless called an antique compass(!) in the sale's email listing - a non-picker alert, you could say.
But my eyes popped out when I saw it, as yours would have as well.

A second thing going in my favor as a potential buyer on Friday was that the chronometer was priced at a healthy $1,950., a number sure to turn away just about everyone else otherwise attracted to this eye candy.
What I did right: I researched it, calling my friend Tom Brunton and long-time chronometer expert John Huber, in Tennessee, for help.
What I did wrong: Thinking I could get it for half-price on Sunday (today), I didn't go back on Saturday.
Of course, a local clockmaker who was not so thrifty did a grab-and-go first thing yesterday morning at full price. He didn't mess around. Should he have?
Well this is what I learned: the clock doesn't have to be working to be worth twice what it was offered at. But how it is NOT working is important. A broken balance staff "is not a real big deal," according to John Huber. Sure, the staff will cost you, but a bad spring detent by itself, he says, would pretty much cut the value of the timepiece in half (after the necessary and expensive call to Huber or to Dewey Clark, another chronometer expert).
And you cannot determine the condition of the spring detent without actually looking down at the movement.
I guess the message here is that you are taking a big risk buying a marine chronometer at auction unless you can either see for yourself or trust the auctioneer's word that the spring detent is in good order.

Tom Brunton can add other nuances about shipping etc. that should also make a buyer sit up and listen, but I hope my tale is instructive.

Cheers anyway!

kh

Just to add that the balance must be corked and the chronometer partly wound for safe shipping ,as I have learned to my chagrin and extreme repair cost LOL

And here's a follow-up link to instructions from early last century for servicing a marine chronometer:

Turn-of-the-century Wisdom for Today

kh