Final Sail is the eleventh in the Dead-End Job series by Elaine Viets - a series that she appears to have gotten the rights back to, and has put out as e-books. Most of the titles in this series have been either free or on sale pretty cheap at various times in the past, but I haven't seen this one free before, so here it is... There are also a couple of omnibuses of series titles that have been free in the past, so you may already have this title, but since it's free, you can also pick it up if you just want to have it individually as well

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Kindle US:
https://www.amazon.com/dp/B079TH87J1
Kindle UK:
https://www.amazon.co.uk/dp/B079TH87J1