I am in Chuts l’arets visiting family. My family might be going on a fishing trip that would require us to leave before sunrise. It won’t be possible to daven on the way, and I don’t think I will have the opportunity to daven with concentration on the small boat that we would be renting. I am aware that for people who have to go to work there is a leniency to daven before sunrise. Does this leniency also apply here?

ב"ה Shalom You have correctly worded your question, because the poskim who allow Tefilla before sunrise, allow it only in restricting circumstances. However, since you are travelling with family, I assume somewhere along the way while travelling you will make some rest stop, perhaps after sunrise and you can daven then and there. Or if necessary, daven while riding in the car and then ask to stop to so you can stand for Shmoneh Esrey at least. There are situations when a person, can say Shmoneh Esrey while seated as well. If these requests, bring about unnecessary stress in the family, then you can reply upon the leniency of Davening before sunrise, and technically, you can fulfill your requirement of Tefilla as I describe below. But, this should not become a regular practice, when travelling for pleasure. However, you must be aware, that while some parts of the tefilla may be said after "amud Hashachar", the time of Tallit and Tefillin comes later. You may consult websites such as "My Zmanin" which give you accurate times for Tefilla, Tallit and Tefillin globally. Since, I felt from your question that the it is crucial for your family member to fish before or just after sunrise, I consulted a veteran fisherman with more than fifty years fishing experience. He said, that when fishing in freshwater, even during the summer it is really not so essential to fish around sunrise as long as it is morning hours before it gets hot. In saltwater the behavior of the fish is dependent the tides. Though, I wasn't requested to voice my opinion about fishing and neither do I see myself in any a fisherman, I felt this information has relevance since your Davening which may cause a delay Tefilla, Tallit and Tefillin before sunrise: The Shulchan Aruch says that under extreme circumstances one may daven and also say Kriyat Shema after "Amud Hashachar" which is before sunrise. However, even under these circumstances, the Magen Avraham and Mishna Brura both say that the bracha of "Yotzer Or" should not be said until the time of Talit and Tefillin. In regard to putting on Talit and Tefillin, one may put them on before "Amud Hashachar" but may not say the Bracha until the time of Talit and Tefillin. When that time comes he should move his Tefillin a bit and then say the Bracha. All the best