Open water = fog + mist + spray. Don’t want spill from a regular reflector light, so that leaves either a tight TIR, an aspheric, or a LEP.
Aspherics (zoomies) are best and cheapest, but the least waterproof due to the moving head. The JaxMan Z1 (nice version of the Cometa, which I got) would be great.
A tight TIR like the 2 Acebeams (L17/L19??) might work great, but don’t recall their cost.
A LEP would be best for longest “punch”, but they’re the priciest.
Something with a very narrow TIR optic or LEP. LEPs are over $100 euros for a cheap one though. I recommend the Acebeam L17 or L18. The L17 is closer to your budget around $50 euro, but the L18 is the next best choice becsuse the beam is more useful and it takes 21700 batteries for longer runtime. Its around 70 euro.
Have you thought about the 4x18a convoy that uses 4 nateria 18650? should last long enough. A hotter xhp70 led should give little reflection. If you prefer to play star wars use 4x18s with sbt90.
Anyone that even tries to answer this question is really giving you bad advice. At the end of the day, it’s up to you. A flashlight is a tool. What kind of tool you use is up to you.
I always assume the questioner knows that, and is looking for the reasons some models fit specific uses. Otherwise there would just be 1 or 2 flashlights. I don’t want to live in that world.
I’ll be interested to hear if you feel it still has too much spill on the water.
I don’t see where Acebeam claims the L18 has low voltage protection, but reviews state it does, and you have a battery level indicator, I wouldn’t worry about protected batteries.
The use case for me is mostly spotting marks on the water which don’t have lights. I think a thrower is a great light for that. Apart from that it’s great to amaze friends with the range :-p.
For everything else than this I use my armytek wizard Pro headlamp. You need both hands while sailing and you can set it exactly to the amount of light you want. Especially the moonlight modes are great because you retain night vision. In my opinion good moonlight modes are way better than red lights.
I also just got my lt1. That’s probably great for inside the cabin although lighting is almost all ready installed there.