[Public-List] USCG Alert re sailboat nav lights' vertical angle

[Michael Connolly]

George and John,
I don't know the beam angle of the LED. There is only one LED flat square pad on this replacement lamp. I assume that the light just comes straight off the LED pad. The glass lenses I have are dome shaped and are about 1-1/4" half sphere. The bronze housing covers most of the lens except at the leading edge. I assumed that the light emitted from the source, either LED or incandescent illuminates the entire inside of the half sphere lens and then exits only where permitted by the opening in the bronze housing. In my understanding the entire glass globe glows with light. There is no attempt of the glass to focus the emitted illumination. Whatever escapes through the bronze housing is available to be broadcast. I assume the distance that it can be seen is based on the candle power of the illumination source.

My boat #133 has the original 1966 navigation light fixtures. This is really low tech stuff. I assumed that if these qualified in 1966 for two miles visibility using the incandescent lamps to "glow" the glass dome that the LED would do the same. Maybe I can do some tests.

Michael

> On April 6, 2019 at 3:58 PM George Dinwiddie via Public-List <public-list at lists.alberg30.org mailto:public-list at lists.alberg30.org > wrote:
> 
> 
>     What is the beam angle of the LED lamp? The angle of the incandescent is
>     360 degrees.
> 
>     On 4/6/19 3:51 PM, Michael Connolly via Public-List wrote:
> 
>         > > George,
> >         These are my original navigation lights on the sides of the coach. Inside there is a glass lens most of which is covered by the bronze housing. The incandescent lamp Ge 9002 is about the size of a dime. Supposed to be two mile visibility. The single LED which fits the same socket is also rated at two mile visibility. I was assuming that the glass lens was responsible for the dispersion of the light. I am not changing the angle or position of the lamp fixture. What do you think? Newer Alberg 30's have these lights near the bow mine are back on the forward sides of the coach.
> >         Michael #133
> > 
> >             > > > On April 4, 2019 at 11:02 PM George Dinwiddie <gdinwiddie at alberg30.org mailto:gdinwiddie at alberg30.org mailto:gdinwiddie at alberg30.org mailto:gdinwiddie at alberg30.org > wrote:
> > > 
> > >         > > 
> >     > >>
>     >> No, because LED lamps have different angles of illumination than incandescent. A single LED has a quite narrow beam. Lamps are designed with multiple LEDs and diffusers to create a wider beam.
>     >>
>     >> George
>     >>
>     >> Sent from a primitive pocket computer. Please assume all errors are due to that.
>     >>
>     >> > > On Apr 4, 2019, at 22:45, Michael Connolly via Public-List <public-list at lists.alberg30.org mailto:public-list at lists.alberg30.org mailto:public-list at lists.alberg30.org mailto:public-list at lists.alberg30.org > wrote:
>     >>>
>     >>> George,
>     >>> I am assuming that if I am just changing the lamp and not the entire fixture that I am still good. Unless the requirements have changed significantly since 1966.
>     >>> Michael
>     >>>
>     >>> > > > On April 4, 2019 at 5:47 PM George Dinwiddie via Public-List <public-list at lists.alberg30.org mailto:public-list at lists.alberg30.org mailto:public-list at lists.alberg30.org mailto:public-list at lists.alberg30.org mailto:public-list at lists.alberg30.org mailto:public-list at lists.alberg30.org mailto:public-list at lists.alberg30.org mailto:public-list at lists.alberg30.org > wrote:
>     >>>>
>     >>>>
>     >>>> Or
>     >>>> https://www.dco.uscg.mil/Portals/9/DCO%20Documents/5p/CG-5PC/INV/Alerts/0219.pdf
>     >>>> so the link doesn't get broken.
>     >>>>
>     >>>> On 4/4/19 4:38 PM, David Tessier via Public-List wrote:
>     >>>>
>     >>>> >> https://www.dco.uscg.mil/Portals/9/DCO Documents/5p/CG-5PC/INV/Alerts/0219.pdf
>     >>>>
>     >>>> > > > >
>     >>>>> > > > > > --
>     >>>>>>
>     >>>>>> > > > >
>     >>>>> > > > ----------------------------------------------------------------------
>     >>>> When I remember bygone days George Dinwiddie
>     >>>> I think how evening follows morn; gdinwiddie at alberg30.org mailto:gdinwiddie at alberg30.org mailto:gdinwiddie at alberg30.org mailto:gdinwiddie at alberg30.org mailto:gdinwiddie at alberg30.org mailto:gdinwiddie at alberg30.org mailto:gdinwiddie at alberg30.org mailto:gdinwiddie at alberg30.org
>     >>>> So many I loved were not yet dead, http://www.Alberg30.org
>     >>>> So many I love were not yet born. also see:
>     >>>> 'The Middle' by Ogden Nash http://idiacomputing.com
>     >>>> ----------------------------------------------------------------------
>     >>>>
>     >>>>
>     >>>>
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> >     >     --
>     ----------------------------------------------------------------------
>     When I remember bygone days George Dinwiddie
>     I think how evening follows morn; gdinwiddie at alberg30.org mailto:gdinwiddie at alberg30.org
>     So many I loved were not yet dead, http://www.Alberg30.org
>     So many I love were not yet born. also see:
>     'The Middle' by Ogden Nash http://idiacomputing.com
>     ----------------------------------------------------------------------
> 
> 
> 
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