VRB-25

<h2 id="components">Components</h2>

A microprocessor controlled 12 volt DC motor drives an array of six or eight <a href="/facts/Poly(methyl_methacrylate)/CnCRBo5F">acrylic</a> <a href="/facts/Fresnel_lens/WYbDj3sn">Fresnel lenses</a> around a bulb at one of 248 speeds ranging from 0.5 to 15.9 revolutions per minute (RPM). In the simplest case, all six lenses are used, so that for <a href="/facts/Boon_Island_Light/jdJ3GYG6">Boon Island Light</a>, which shows one flash every five seconds, the mechanism rotates at two RPM. Eight lenses are used only when required to achieve more complex <a href="/facts/Light_characteristic/QUzeA9R0">characteristics</a>.
Maximum range is achieved by using the slowest possible speed, but for grouped flashes, it is necessary to blank off lenses and rotate the mechanism faster. So, for example, for <a href="/facts/The_Cuckolds_Light/uX5npww4">The Cuckolds Light</a>, whose characteristic is group flashing two every six seconds, all but two of the six panels are blanked off and the mechanism rotates at ten RPM.
The mechanism is driven by a DC thirty-pole three phase brushless direct drive motor which consumes approximately 1.5 watts. The microprocessor controller keeps the motor speed within 2% of that chosen, using optical sensing of a circular pattern of alternating black and silver lines located around the bottom of the turntable. This provides a feedback signal for speed control. The unit is designed to accept voltages ranging from 11 to 30 volts. Since the life of an <a href="/facts/Incandescent_light_bulb/31frjg0A">incandescent</a> lamp decreases dramatically as the applied voltage increases, the lamp voltage is carefully maintained at 12.00V using <a href="/facts/Pulse-width_modulation/cqjcrYs7">pulse-width modulation</a>.
The lamps, standard marine signal lamps<a class="footnote-ref" id="fnref:2" href="#fn:2">2</a> which may be from 10 to 100 watts as required to produce the necessary range, typically have a life of 2,000 hours. The unit contains a bulb changing mechanism which holds six bulbs, so that a unit could go approximately three years between maintenance visits to change bulbs. The acrylic lenses and cylinder surrounding the whole mechanism are designed to be <a href="/facts/Ultraviolet/kncBUqn5">UV</a> resistant, but still require replacement approximately every five years.<a class="footnote-ref" id="fnref:3" href="#fn:3">3</a> In practice, since working lights are critical to navigation, the Coast Guard actually services lights more frequently. Except for that maintenance, the unit is expected to last twenty years.

<h2 id="predecessors-and-successors">Predecessors and successors</h2>
In the 2010s, <a href="/facts/LED/gE8x4MDb">LED</a> lamps began replacing incandescent lamps in lighthouse applications,<a class="footnote-ref" id="fnref:4" href="#fn:4">4</a> so it seems likely the twenty year replacement will use an LED light source. In fact, several VLB-44 LED beacons,<a class="footnote-ref" id="fnref:5" href="#fn:5">5</a> also made by Vega Industries, have been installed by the USCG at several locations, including <a href="/facts/White_Island_Light/RpmQclkS">White Island Light</a><a class="footnote-ref" id="fnref:6" href="#fn:6">6</a> and <a href="/facts/Wood_Island_Light/4DsFxqrW">Wood Island Light</a>.<a class="footnote-ref" id="fnref:7" href="#fn:7">7</a> In at least one case, a VLB-44 was removed and returned to a VRB-25 in 2022 at <a href="/facts/Whaleback_Light/27Vz4Y3M">Whaleback Light</a> to maintain the rotating light signature.<a class="footnote-ref" id="fnref:8" href="#fn:8">8</a>
From the first use of lighthouses with flashing lights, the light source has been continuous, because turning a flame on and off is impractical and flashing an incandescent electric lamp reduces its life substantially. The flashing light signature seen by the observer has been achieved by rotating a lens system. Since LEDs can be flashed on and off without degrading their lives, it is likely the VRB-25 is the last use of rotating beacons in lighthouses.

<h2 id="issues">Issues</h2>
Although the units have been successful in their adoption, there has been occasional controversy (at <a href="/facts/Egg_Rock_Light_(Maine)/TLXtjP53">Egg Rock Light</a> in Maine, for example<a class="footnote-ref" id="fnref:9" href="#fn:9">9</a>) when the Coast Guard has removed the lantern from the tower after installing a VRB-25. This seemed logical since the lantern required maintenance and the VRB-25 is designed to sit outside, but it changed the traditional look of the towers. After public protest, a replacement lantern house was installed at Egg Rock Light in 1986. All the VRB-25s listed below, except Piedras Blancas, still have lanterns.<a class="footnote-ref" id="fnref:10" href="#fn:10">10</a>
While the beam is visible at its listed range, it is a more focused beam than that produced by a glass Fresnel lens. Some navigators don't like this, finding it harder to see under some conditions.<a class="footnote-ref" id="fnref:11" href="#fn:11">11</a> It is easy to see the difference from many points around Boston Harbor, where the VRB-25 at <a href="/facts/The_Graves_Light/vus3uXdN">The Graves Light</a> and the 2nd order glass Fresnel lens at <a href="/facts/Boston_Light/N7Qb1Wau">Boston Light</a> are both visible. Of course, the original first order Fresnel lens at The Graves stood twelve feet high and weighed several tons. Its many pieces of glass required periodic careful cleaning and alignment.

<h2 id="examples-of-lights-using-the-vrb-25">Examples of lights using the VRB-25</h2>
<table><tbody><tr><th>Light</th><th>Location</th><th>Characteristic</th><th>Range (nautical miles)</th></tr><tr><th scope="row" rowspan="1"><a href="/facts/Cape_Moreton_Light/xF7wI9dn">Cape Moreton Light</a> </th><td><a href="/facts/Queensland/lXBlIeY3">Queensland</a><a href="/facts/Australia/qLHpbppq">Australia</a></td><td>Fl(4) W 20s</td><td>15</td></tr><tr><th scope="row" rowspan="1"><a href="/facts/DeTour_Reef_Light/VuukaK1d">DeTour Reef Light</a> </th><td><a href="/facts/Chippewa_County,_Michigan/ysqjTkul">Chippewa County</a><a href="/facts/United_States/P0sCdLe5">United States</a><a class="footnote-ref" id="fnref:12" href="#fn:12">12</a></td><td>Fl W 10s</td><td>16 (white), 13 (red)</td></tr><tr><th scope="row" rowspan="1"><a href="/facts/The_Graves_Light/vus3uXdN">The Graves Light</a> </th><td><a href="/facts/Boston/exjfn6xf">Boston</a><a href="/facts/United_States/P0sCdLe5">United States</a><a class="footnote-ref" id="fnref:13" href="#fn:13">13</a></td><td>Fl(2) W 12s</td><td>15</td></tr><tr><th scope="row" rowspan="1"><a href="/facts/Mount_Desert_Light/Ys98d9WF">Mount Desert Light</a> </th><td><a href="/facts/Frenchboro,_Maine/BBFppQFu">Frenchboro</a><a href="/facts/United_States/P0sCdLe5">United States</a><a class="footnote-ref" id="fnref:14" href="#fn:14">14</a></td><td>Fl W 15s</td><td>20</td></tr><tr><th scope="row" rowspan="1"><a href="/facts/Piedras_Blancas_Light_Station/RPrFcPvP">Piedras Blancas Light Station</a> </th><td><a href="/facts/San_Simeon,_California/a2fIwJ4S">San Simeon</a><a class="footnote-ref" id="fnref:15" href="#fn:15">15</a><a href="/facts/United_States/P0sCdLe5">United States</a><a class="footnote-ref" id="fnref:16" href="#fn:16">16</a></td><td>Fl W 10s</td><td>21</td></tr><tr><th scope="row" rowspan="1"><a href="/facts/Thimble_Shoal_Light/vy6kbxly">Thimble Shoal Light</a> </th><td><a href="/facts/Norfolk,_Virginia/PPAclcuM">Norfolk</a><a href="/facts/United_States/P0sCdLe5">United States</a><a class="footnote-ref" id="fnref:17" href="#fn:17">17</a></td><td>Fl W 10s</td><td>18</td></tr><tr><th scope="row" rowspan="1"><a href="/facts/West_Point_Light/YaIgV6LA">West Point Light</a> </th><td><a href="/facts/Seattle/7lYIrCa6">Seattle</a><a href="/facts/United_States/P0sCdLe5">United States</a><a class="footnote-ref" id="fnref:18" href="#fn:18">18</a></td><td>Alt WR 10s</td><td>16 (white), 13 (red)</td></tr></tbody></table>

<h2 id="external-links">External links</h2>
<ul><li><a href="http://www.terrypepper.com/lights/closeups/illumination/acrylic/VRB-25/index.htm">Terry Pepper, Seeing the Light "Vega VRB-25 Rotating beacon"</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1">US Coast Guard (2008). Short Range Aids to Navigation Servicing Guide. pp. 3–50. <a href="#fnref:1" class="footnote-back-ref">↩</a></li>
<li id="fn:2">US Coast Guard (2002). Major Aids to Navigation Preventative Maintenance Guide. p. 6-E(17)-A-1. <a href="#fnref:2" class="footnote-back-ref">↩</a></li>
<li id="fn:3">Vega Industries, Ltd. (2009). VRB-25 Technical Design Paper. p. 3.10. <a href="#fnref:3" class="footnote-back-ref">↩</a></li>
<li id="fn:4">Bob Trapani Jr. (Summer 2009). "Vega VRB-25 – Last of the Lighthouse Rotating Beacons as We Know Them". The Keeper's Log. U.S. Lighthouse Society. Archived from the original on 2009-06-02. Retrieved 2009-09-04. Article is also available as PDF from U.S. Lighthouse Society <a href="https://web.archive.org/web/20090602093946/http://www.stormheroes.com/aton/vrb25_200904.htm" target="_blank">https://web.archive.org/web/20090602093946/http://www.stormheroes.com/aton/vrb25_200904.htm</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></li>
<li id="fn:5">Vega Industries, Ltd. (2009-09-04). "VLB-44 LED Marine Beacon" (PDF). Archived from the original (PDF) on 2010-05-24. Retrieved 2009-09-04. <a href="https://web.archive.org/web/20100524154530/http://vega.co.nz/assets/pdf%20files/vlb-44_2.pdf" target="_blank">https://web.archive.org/web/20100524154530/http://vega.co.nz/assets/pdf%20files/vlb-44_2.pdf</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></li>
<li id="fn:6">Bob Trapani Jr. (Summer 2009). "Vega VRB-25 – Last of the Lighthouse Rotating Beacons as We Know Them". The Keeper's Log. U.S. Lighthouse Society. Archived from the original on 2009-06-02. Retrieved 2009-09-04. Article is also available as PDF from U.S. Lighthouse Society <a href="https://web.archive.org/web/20090602093946/http://www.stormheroes.com/aton/vrb25_200904.htm" target="_blank">https://web.archive.org/web/20090602093946/http://www.stormheroes.com/aton/vrb25_200904.htm</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></li>
<li id="fn:7">Trapani Jr., Bob (December 18, 2012). "A New Bright Shine at Wood Island Lighthouse". American Lighthouse Foundation. Retrieved 31 December 2024. <a href="https://lighthousefoundation.org/2012/12/a-new-bright-shine-at-wood-island-lighthouse/" target="_blank">https://lighthousefoundation.org/2012/12/a-new-bright-shine-at-wood-island-lighthouse/</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></li>
<li id="fn:8">Trapani Jr., Bob (December 28, 2022). "Looking Back on 2022 – Whaleback Lighthouse". American Lighthouse Foundation. Retrieved 31 December 2024. <a href="https://lighthousefoundation.org/2022/12/looking-back-on-2022-whaleback-lighthouse/" target="_blank">https://lighthousefoundation.org/2022/12/looking-back-on-2022-whaleback-lighthouse/</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></li>
<li id="fn:9">Rowlett, Russ (2009-09-01). "Lighthouses of the United States: Eastern Maine". The Lighthouse Directory. University of North Carolina at Chapel Hill. <a href="https://www.ibiblio.org/lighthouse/me.htm" target="_blank">https://www.ibiblio.org/lighthouse/me.htm</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></li>
<li id="fn:10">Rowlett, Russ (2009-09-03). "The Lighthouse Directory". University of North Carolina at Chapel Hill. <a href="https://www.ibiblio.org/lighthouse/index.htm" target="_blank">https://www.ibiblio.org/lighthouse/index.htm</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></li>
<li id="fn:11">Bob Trapani Jr. (Summer 2009). "Vega VRB-25 – Last of the Lighthouse Rotating Beacons as We Know Them". The Keeper's Log. U.S. Lighthouse Society. Archived from the original on 2009-06-02. Retrieved 2009-09-04. Article is also available as PDF from U.S. Lighthouse Society <a href="https://web.archive.org/web/20090602093946/http://www.stormheroes.com/aton/vrb25_200904.htm" target="_blank">https://web.archive.org/web/20090602093946/http://www.stormheroes.com/aton/vrb25_200904.htm</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></li>
<li id="fn:12">archINFORM (in German, English, French, Spanish, and Italian), OCLC 45382278, Wikidata Q265049 <a href="https://www.archinform.net" target="_blank">https://www.archinform.net</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></li>
<li id="fn:13">archINFORM (in German, English, French, Spanish, and Italian), OCLC 45382278, Wikidata Q265049 <a href="https://www.archinform.net" target="_blank">https://www.archinform.net</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></li>
<li id="fn:14">archINFORM (in German, English, French, Spanish, and Italian), OCLC 45382278, Wikidata Q265049 <a href="https://www.archinform.net" target="_blank">https://www.archinform.net</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></li>
<li id="fn:15">archINFORM (in German, English, French, Spanish, and Italian), OCLC 45382278, Wikidata Q265049 <a href="https://www.archinform.net" target="_blank">https://www.archinform.net</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></li>
<li id="fn:16">archINFORM (in German, English, French, Spanish, and Italian), OCLC 45382278, Wikidata Q265049 <a href="https://www.archinform.net" target="_blank">https://www.archinform.net</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></li>
<li id="fn:17">archINFORM (in German, English, French, Spanish, and Italian), OCLC 45382278, Wikidata Q265049 <a href="https://www.archinform.net" target="_blank">https://www.archinform.net</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></li>
<li id="fn:18">archINFORM (in German, English, French, Spanish, and Italian), OCLC 45382278, Wikidata Q265049 <a href="https://www.archinform.net" target="_blank">https://www.archinform.net</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></li>
</ol>

VRB-25 open-in-new

VRB-25