One of the most nerve wracking issues many boaters face has been able to safely anchor for extended periods when on long cruises. Some of the worst stories you'll hear involve folks who found what they thought would be a safe anchorage well far from regular traffic, simply to wake in the middle of the night time to find another vessel bearing down on 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'. Way too many boaters assume because they are well removed from the lanes of ordinary traffic and in what is apparently a fairly acceptable position, they are thus safe from potential collisions, and so think nothing of saving a couple of amps of power by not running a dedicated anchor light. Even worse, some boaters have a tendency to utilize anchor lights which are woefully inadequate or improperly placed, making its use a real 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, and then how many all around anchor lights you see illuminated once darkness falls. You will probably be more than a little surprised. - Anchor Lights
It truly is unfortunate that many boaters neglect to give enough focus on their anchor lighting. Though it is true that an anchor light producing the standard minimum visibility as outlined in Inland Navigational rules can produce a substantial drain on battery reserves throughout a night, the potential consequences of not running one, as well as the energy efficient options available, really eliminate any justification because of not running one. It simply is not worth the risk of collision, or perhaps the fines and citations that come with being out of compliance, in order to reduce the drain on your power reserves. You will find safer ways to save power and still maintain compliance, and all it takes is a little knowledge and willingness to try something new.
The full text of Navigational Rules can be found online at the USCG's website, and so they outline what you being a boater need to know in order to maintain safe and compliant lighting operation. Rule 30 in particular references anchored and aground vessels, and we'll include it here for convenience.
"Rule 30 - Anchored Vessels and Vessels Aground"
(a) A vessel at anchor shall exhibit where it could best be seen: (i) in the fore part, an all-round white light a treadmill ball;
(ii) at or close to 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 rather than the lights prescribed in paragraph (a) of the Rule.
(c) A vessel at anchor may, along with a vessel of 100 meters plus more in length shall, also employ 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 are able to best be seen; (i) two all-round red lights in the vertical line;
(ii) three balls inside a vertical line.
(e) A vessel of lower than 7 meters in total, when at anchor not in or near a narrow channel, fairway or where other vessels normally navigate, shall not required to exhibit the shape prescribed in paragraphs (a) and (b) with this Rule.
(f) A vessel of under 12 meters long, when aground, shall not be required to exhibit the lights or shapes prescribed in subparagraphs (d)(i) and (ii) of this Rule.
(g) A vessel of lower than 20 meters in length, when at anchor in the special anchorage area designated by the Secretary, shall not required to exhibit the anchor lights and shapes required by this Rule.
As you can see, an anchor light is not an option, but a legal requirement. So, exactly how is it possible to run a compliant anchor light for hours without producing a substantial drain on your battery reserves? Well, the best option these days involves upgrading from the 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 to the 2 nautical mile requirement, causing them to be at best adequate, at worst difficult to see if conditions are less than ideal. As we run a 1 amp anchor light for 10 hours, that's 10 amps pulled from the battery bank, which can add up if you also consider you'll likely be running cabin fans and interior lighting too.
An LED anchor light alternatively will operate about 80% more proficiently than an incandescent version. A typical incandescent bulb puts out about 15 lumens per watt, plus an LED about 60 to 70 lumens per watt. This means you can produce a much brighter All over signal while pulling far 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 less than 1 amp. This could knock down power consumption to around 3-4 amps after 10 buisness hours, showing not only less battery drain, but improved output as well.
With this kind of performance, there is just no real reason any boater should skimp about the safety and security of an anchor light just to try saving a couple of amps of power, particularly when they can knock power consumption down a great deal with just a fixture change. You are able to produce a brighter signal which will be easier for other boaters to see, even in less than ideal conditions, reduce power use, and maintain compliance with navigation regulations, simply by simply upgrading to LEDs in your anchor light. - Anchor Lights