One of the more nerve wracking issues many boaters face is being able to safely anchor for extended periods when on long cruises. A few of the worst stories you'll hear involve people who found what they thought would be a safe anchorage well from regular traffic, only to wake in the middle of the night to find another vessel bearing upon them in the darkness. Unfortunately, this is just as often the fault of the boat owner as it is the owner of the underway vessels'. A lot of boaters assume since they're well removed from the lanes of ordinary traffic and in what appears to be a fairly acceptable position, that they are thus safe from potential collisions, therefore think nothing of saving several amps of power by not running a dedicated anchor light. A whole lot worse, some boaters tend to utilize anchor lights which can be woefully inadequate or improperly placed, making its use a legitimate moot point. If you doubt a realistic look at all this, simply take time to note at sunset the number of vessels are anchored at the next time you are out, then how many all around anchor lights you see illuminated once darkness falls. Chances are you'll be more than a little surprised.- Anchor Lights
It really is unfortunate that many boaters don't give enough focus on their anchor lighting. Even though it is true that an anchor light producing the typical minimum visibility as outlined in Inland Navigational rules can create a substantial drain on battery reserves over the course of a night, the potential consequences of not running one, as well as the energy efficient options available, really take away any justification for not running one. It really is not worth the risk of collision, or even the fines and citations that include being out of compliance, just to reduce the drain on your power reserves. There are safer ways to save power but still maintain compliance, and many types of it takes is a little knowledge and willingness to use something new.
The full text of Navigational Rules is found online at the USCG's website, and they outline what you being a boater need to know in order to maintain safe and compliant lighting operation. Rule 30 specifically references anchored and aground vessels, and we'll include it in charge of convenience.
"Rule 30 - Anchored Vessels and Vessels Aground"
(a) A vessel at anchor shall exhibit where it can best be seen: (i) in the fore part, an all-round white light or one ball;
(ii) at or nearby the stern and at a lesser level than the light prescribed in subparagraph (i), an all-round white light.
(b) A vessel of less than 50 meters in total may exhibit an all-round white light where it can best be seen as opposed to the lights prescribed in paragraph (a) of the Rule.
(c) A vessel at anchor may, and a vessel of 100 meters and much more in length shall, likewise use the available working or equivalent lights to illuminate her decks.
(d) A vessel aground shall exhibit the lights prescribed in paragraph (a) or (b) with this Rule and in addition, if practicable, [Inld] where they could best be seen; (i) two all-round red lights in a vertical line;
(ii) three balls in the vertical line.
(e) A vessel of under 7 meters in length, when at anchor not in or near a narrow channel, fairway or where other vessels normally navigate, shall not required to exhibit the design prescribed in paragraphs (a) and (b) of the Rule.
(f) A vessel of under 12 meters in length, when aground, shall 't be required to exhibit the lights or shapes prescribed in subparagraphs (d)(i) and (ii) with this Rule.
(g) A vessel of less than 20 meters in length, when at anchor inside a special anchorage area designated from the Secretary, shall not be required to exhibit the anchor lights and shapes essental to this Rule.
As you can tell, an anchor light isn't an option, but a legal requirement. So, precisely how is it possible to run a compliant anchor light for hours without producing a substantial drain on your battery reserves? Well, the best choice these days involves upgrading from your old incandescent bulb anchor light to 1 outfitted with LEDs. An old incandescent style anchor light can pull between 1 to 3 amps per hours from your 12 volt electrical system. Worse, these incandescent lights are very often just barely visible for the 2 nautical mile requirement, making them at best adequate, and also at worst difficult to check if conditions are less than ideal. As we run a 1 amp anchor light for 10 hours, which is 10 amps pulled from the battery bank, which accumulates if you also consider you will likely be running cabin fans and interior lighting as well.
An LED anchor light on the other hand will operate about 80% more effectively than an incandescent version. A normal incandescent bulb puts out about 15 lumens per watt, as well as an LED about 60 to 70 lumens per watt. And that means you can produce a much brighter 360 degree signal while pulling much less power. If your current 3 watt anchor light produces 45 lumens, you can get a 1 watt LED that will produce around 60, and pull under 1 amp. This may knock down power consumption to around 3-4 amps after 10 hours of operation, showing not only less battery drain, but improved output also.
With this kind of performance, there's just no real reason why any boater should skimp about the safety and security of an anchor light just to try saving several amps of power, particularly when they can knock power consumption down a great deal with just a fixture change. You can produce a brighter signal that'll be easier for other boaters to determine, even in less than ideal conditions, reduce power use, and keep compliance with navigation regulations, all by simply upgrading to LEDs in your anchor light. - Anchor Lights