Battery powered Nav Lights - which ones to buy?

I bought mine from West Marine. 2 Small LED flashlights one all round white and one combined red green.
Cheep work well and have been used when one of my side lights failed on passage.
 
Perhaps the real question is how and where you are going to attach emergency nav lights. That may dictate the best design for you. Bare in mind that you may need to fit in rough water on wet boat at night. However to answer OP question for my tiny boat for emergency lights I made some out of old incandescent nav light housings. I fitted 3 LED on wires to a tag board and bent them on the leads so that they faced forward , to the side and at 45 degrees. They are powered by a single lithium rechargeable 14500 or 18650 that fit in a holder glued to the under side of the light housing. I used a 47 ohm series resistor for the 3 LED wired in parallel. The whole thing is taped to the side of the cabin with gaffer tape (duct tape) over the body but leaving lens clear. A stern white light is perhaps more easily fabricated although you could rely on a couple of flashlights taped to pushpit at a splayed angle to give coverage. I presume this is for racing category inspection in which case much depends on what your inspector will accept as well as being actually useable. ol'will
 
I’ve got these LED Flex Emergency Navigation Lights Set of 3 Waterproof Boat Sailing J68 5204980726638 | eBay for my boat which is a 40 foot sailing boat. They’re more reliable than the screw down versions and easy to fit to the pulpit and pushpit rails.


They look snazzy ... question : Looking at the eBay picture - they appear as though angle of shut off is not there ? can you give a better description ... maybe even a piccy on your boat clipped in place ...

Why I ask ? Here's an admission ... 2011 departing home port .... Ferry was coming out behind us and both of us looked astern to see ....... BHAM ! Port bow hit the outer fairway buoy and smashed my port sidelight on the pulpit. I then had to sail to Gotland minus port light.

It happens !!
 
Given that they’re emergency lights I’m not too fussed on sharply defined cutoff angles.... The construction of the lights is such that if the fore lights mounted on a vertical pole and the aft light mounted on a horizontal pole, they’ll deliver more or less the right angles for their positions. The other type with the clip fixings and shade are more precise but suffer from two problems: you’ve got to screw the clip fittings in place and secondly the lights themselves are pretty rubbish in terms of reliability (all too often you’ll try to turn them on and they don’t function: the screw down mechanism just doesn’t make reliable contact.)
 
Given that they’re emergency lights I’m not too fussed on sharply defined cutoff angles.... The construction of the lights is such that if the fore lights mounted on a vertical pole and the aft light mounted on a horizontal pole, they’ll deliver more or less the right angles for their positions. The other type with the clip fixings and shade are more precise but suffer from two problems: you’ve got to screw the clip fittings in place and secondly the lights themselves are pretty rubbish in terms of reliability (all too often you’ll try to turn them on and they don’t function: the screw down mechanism just doesn’t make reliable contact.)

I never expect to have precise cut off angles ... its just bad picture I think on eBay - just makes them look as though there is no cut off ...

Was interested in general ...

I have seen examples of the others and a couple had unreliable contacts ...

I fitted this to my motorboat :

s-l225.jpg


and considered buying another and adding a clip bracket + small 3S LiPo battery ... as it really works well ...
 
I had it in mind to just cable tie the clips rather than screwing them to something if I needed to use them. I'd struggle to find something to screw them to...
 
I acquired some Plastimo ones with the boat, and as well as the light output being pretty minimal, they have a tendency to run the battery down in storage.
 
I acquired some Plastimo ones with the boat, and as well as the light output being pretty minimal, they have a tendency to run the battery down in storage.


Old trick .... with items you leave batterys in ... get a piece of thin card or plastic sheet ... cut to size with a tab .. place on top of battery end and close. This prevents contact but still has battery in - so you don't have to hunt for it when time comes. To use ... pull tab and out it comes - battery can now do its job.
 
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