Lasizas Stern Light

Refueler said:
Surely you would be looking for maximum vertical - to allow for pitching ?? ... but limited to cut-off angles horizontal ?
Click to expand...
That's right but that applies to any nav light yet it seems they mostly have the Fresnel sections running horizontal as in post #8.
 
Post #8 misunderstood what a fresnel lens is, and described a specific type. They are actually just flat lenses and can work in pretty much any way a normal lens does just with less material and thickness.

You might want to delete one of your accounts, it’s confusing when you reply from different personas, and breaks forum rules.
 
lustyd said:
Post #8 misunderstood what a fresnel lens is, and described a specific type. They are actually just flat lenses and can work in pretty much any way a normal lens does just with less material and thickness.

You might want to delete one of your accounts, it’s confusing when you reply from different personas, and breaks forum rules.
Click to expand...
I am familiar with Fresnel lenses, linear and circular but your final point, are you suggesting that I have multiple accounts?

Edit: If so what is my other "persona"?
 
S04 said:
I am familiar with Fresnel lenses, linear and circular but your final point, are you suggesting that I have multiple accounts?
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Well, you’re (S04) talking as if you’re the OP (SteveIOW). If not then apologies and good of you to raise a support ticket on his behalf.
 
OK, my name is Chris and I live in Cumbria and I assume SteveIOW is called Steve and lives on or is from the IoW (perhaps he can confirm my guess).

I raised the ticket with Lalizas as I was interested in finding out the answer to the mounting question as there were differing opinions.
 
The details are in COLREGS annex I. Also intensity, horizontal sectors, and position. It is interesting to note that powerboat lights do not meet the same requirements are sailboat lights, because of heeling. Anchor lights, obviously, are the same, since you are not underway. The same could be argued for a steaming light. Side lights are the main difference.

10. Vertical sectors
(a) The vertical sectors of electric lights as fitted, with the exception of lights
on sailing vessels underway shall ensure that:
(i) at least the required minimum intensity is maintained at all angles
from 5 degrees above to 5 degrees below the horizontal;
(ii) at least 60 percent of the required minimum intensity is maintained
from 7.5 degrees above to 7.5 degrees below the horizontal.
(b) In the case of sailing vessels underway the vertical sectors of electric
lights as fitted shall ensure that:
(i) at least the required minimum intensity is maintained at all angles
from 5 degrees above to 5 degrees below the horizontal;
(ii) at least 50 percent of the required minimum intensity is maintained
from 25 degrees above to 25 degrees below the horizontal.
(c) In the case of lights other than electric these specifications shall be met
as closely as possible.
 
And I find it interesting that so many like to go on about specs - go to a marina and have a look at boats that have separate side lights fitted to pulpits ... most DO NOT conform to the light sectors due to the angle of the pulpit mouning plates ...
See other boats with side lights fitted to cabintop sides ... again often have an inward angle due to the cabin sides.
 
thinwater said:
The details are in COLREGS annex I. Also intensity, horizontal sectors, and position. It is interesting to note that powerboat lights do not meet the same requirements are sailboat lights, because of heeling. Anchor lights, obviously, are the same, since you are not underway. The same could be argued for a steaming light. Side lights are the main difference.

10. Vertical sectors
(a) The vertical sectors of electric lights as fitted, with the exception of lights
on sailing vessels underway shall ensure that:
(i) at least the required minimum intensity is maintained at all angles
from 5 degrees above to 5 degrees below the horizontal;
(ii) at least 60 percent of the required minimum intensity is maintained
from 7.5 degrees above to 7.5 degrees below the horizontal.
(b) In the case of sailing vessels underway the vertical sectors of electric
lights as fitted shall ensure that:
(i) at least the required minimum intensity is maintained at all angles
from 5 degrees above to 5 degrees below the horizontal;
(ii) at least 50 percent of the required minimum intensity is maintained
from 25 degrees above to 25 degrees below the horizontal.
(c) In the case of lights other than electric these specifications shall be met
as closely as possible.
Click to expand...

So this bit confirms the fresnel elements should run horizontally?
 
S04 said:
That makes sense yes. I was just musing, making an observation. I wasn't trying to be contentious.
Click to expand...

Reason I mentioned that - was that examples of lights shown by some are based on filament bulbs .. and the OP's light is an LED version ... the source light has different chracteristics which may affect which way the DIOPTRICS work ...
 
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