As a recently retired professional mariner I'd like to voice my thoughts on night running with pleasure craft. Coming from the world of heavily built steel hulls to fiberglass I'm very cognizant of the relative frailty of fiberglass. My first thought is that as a pleasure boater I don't “need” to go. I can wait for favorable conditions. I've done a few deliveries of FG boats and avoid night running as much as possible. If the customer is not willing to pay the extra days for daylight running I'm not willing to take the delivery.
Hard semi submerged objects are a real risk. Not just to the hull but your running gear as well. Less hard gear is also a risk. In the near shore PNW waters we have to deal with crab pots. In strong tidal currents they can “disappear” under the surface, but still close enough to the surface to wrap the line around your prop. In daylight there are good clues the pot buoys are there. At night you don't stand a chance of seeing them.
On inland waters on warm nights any number of drunken idiots are out in unlit boats. I once came far to close to running over a canoe. Dark night, dark hull, dark clothes, no lights.
That said, I have to agree with some of the posters. Running at night can be peaceful and beautiful. I've been fortunate enough to have made some trips through the Gulf Islands / San Juan Islands on crystal clear winter nights with a full moon. Fresh snow on the mountains. Breath taking.
I've run in strong bioluminescence with the fish swimming near the surface and making bright streaks as they dart away.
I've also made too many night runs that contributed to my premature aging.
Like all aspects of running boats be prepared. Make sure you have the requisite skills. And as a pleasure boater wait for the right conditions, especially for your first handful of night cruises.
If you choose to accept the risks of hull and running gear damager here are some of the things I think should be considered.
Make sure you running lights are on and bright.
Know your electronics and how to best use them. Radar, chart plotter and AIS. All are important, none alone tell you the whole truth. I can't speak to FLIR having no experience. I can speculate that your view while good is limited. Practice in daylight.
Protect your night vision. No lights near the helm. Dim your screens as much as possible. I used to purchase red plexiglass and tape it over the screens. Do realize that any red objects displayed on the screen disappear. Little bits of black tape over the numerous LED indicators. Screens that do not need to be seen at all times for example VHF displays can be covered with heavy paper and tape. You can peel it off instantly if needed.
Realize and understand that in a very short time you can be in zero visibilty as conditions change. What would be annoying in daylight can leave you with zero visibility at night. If you run at night in cold climates avoid potential snow fall. Heavy snow is the worst possible condition. Even radar has a hard time penetrating heavy snow.
Situational awareness is important any time you are underway. It is especially important at night. Have a mental picture of what is around you. Land, buoys, traffic. We all, professionals and recreational boaters alike are guilty of putting too much faith in the electronics, navigating in the moment. Just keeping the monkey on the string. Instead be old skool. Think ahead to what is coming and where you will be in a few minutes, the next hour, later that night. Night running can be disorienting and confusing. Thinking ahead of the boat reduces that.
If you are in an area frequented by sports fishers understand they like to get going well before daylight and run full throttle in straight lines to their favorite grounds. As far as I can tell they are blind.
Working boats are, well, they're working. Often with bright deck lights on that limit their night vision.
If possible don't stand a night watch alone. An extra set of eyes. A voice in the darkness when you get drowsy.
Be aware of 3:30. It is not, except for partying teenagers, a natural time for humans to be awake. It is neither late nor early. It is just wrong. Your brain will be slow and mushy, your vision not at it's peak. To help deal with that get some good rest, preferably some solid sleep before a night run. Studies of transportation accidents show that the middle of the night is the highest risk.
Embrace the darkness. Look for every sign you might see. Are you near shore? Don't stare at the lights but notice them. Is there a dark patch that seems out of place? You might be staring at the side of a barge or freighter too close to see the running lights. Please don't ask me how I learned that one.... Are you on inland or urban waters? Watch the reflections. Is part of a reflection pattern 'missing'? It might be that unlit canoe. Where is the moon? Is it low and behind you? Then your vision is outstanding, almost as good as daylight. However the vessel coming at you may not be able to see you. Know that your best night vision is not straight ahead. It's a bit off to the side of center. Keep your head on a swivel. Are you feeling drowsy? Stand up, steer by hand, talk to your watch mate.
Neve forget to look behind you. Ever.
Learn to read other vessel's running lights. They tell you a lot once you get the hang of it.
Changing course to avoid a 'big boy'? Show him your bow. Turn enough and hold that course long enough to make your intentions clear. Still not sure he saw you? Turn 90 degrees to his course, preferably to starboard unless that is the long way across his bow. Turn on all of your deck lights, anchor light, search light. Is he still bearing down on you? Shine your search light in his windows, then straight ahead of your bow. Repeat it. You're saying “Wake UP!!!!” and “I'm headed 'that way' “
Night running brings extra challenges, builds skills and can be enjoyable. Break yourself in easy under good conditions on short runs. Make it enjoyable and rewarding.
Thank you for indulging me and letting me ramble on.