Wiring question

I am trying to install a convenience light near my stern light on the roof of the cockpit. I have a primary wire from the panel to the location but do not have a second wire. I am wondering - can I use the primary wire for the positive lead to the light and connect the negative lead to the negative of the stern light?

Yes

Yes you should be able to do that.

It will physically work but no one (that I've ever seen anyway other than PO's) wires a boat to share the negative with maybe the exception of a two bulb fixture like a masthead light. Use the single primary wire to pull a pair of #16 ga tinned marine wire into place.

The only way I know to safely answer the question would be...

1. What is the combined wattage of the lights?
2. What are the individual wire gauges and lengths back to either heavier wire junctions or the source panel?
3. Whether the light sockets could possibly take much higher wattage light bulbs that someone could accidently do without knowing of the shared negative...if so the sockets need warning labels if you proceed and the negative wire gauge could be over taxed.

Why not use a pair of LED lights then you will have the lights as bright as needed and you will reduce the overall current from both fixtures to less than a single filament bulb would draw.
Bill

Billylll said:

Why not use a pair of LED lights then you will have the lights as bright as needed and you will reduce the overall current from both fixtures to less than a single filament bulb would draw.
Bill

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Hollywood

Both lights are LED.
The stern light was originally a 10w socket / bulb. I replaced that light with a LED fiture

HenryD said:

Both lights are LED.
The stern light was originally a 10w socket / bulb. I replaced that light with a LED fiture

Click to expand...

Then you should have no problem using the same ground for both lights.

I agree more than likely the original light wasn't LED either way you will have no issues using a pair of LED fixtures.
Bill

>The stern light was originally a 10w socket / bulb. I replaced that light with a LED fiture.<

>Then you should have no problem using the same ground for both lights. <

However in an accident the use of a LED in a lamp that was certified for a filament bulb could come to bite.

The Fresnel housing is built for a pinpoint 360 deg source , not for a bunch of LED glued to a stalk.

There is a difference between what works , and what works till the liars for hire get involved.

The risk is all yours.

FF said:

However in an accident the use of a LED in a lamp that was certified for a filament bulb could come to bite.

The Fresnel housing is built for a pinpoint 360 deg source , not for a bunch of LED glued to a stalk.

There is a difference between what works , and what works till the liars for hire get involved.

The risk is all yours.

Click to expand...

I don't believe there is any legal risk involved if the light can been seen from two miles or more and the intensity is the same whether the lens has a LED bulb behind it or not.

Capt.Bill11 said:

I don't believe there is any legal risk involved if the light can been seen from two miles or more and the intensity is the same whether the lens has a LED bulb behind it or not.

Click to expand...

From the regulations I have seen and read, the standards are performance based. Any light source that meets the performance standards should be acceptable.

A fixture that is marked with a USCG approval pretty much guarantees that it will meet the performance standard if installed correctly. Otherwise, it's up to you to make sure the standards are met.

It wasn't long ago when sailboaters used kerosene lanterns for anchor lights.

High Wire said:

It will physically work but no one (that I've ever seen anyway other than PO's) wires a boat to share the negative with maybe the exception of a two bulb fixture like a masthead light. .

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This is correct. It will work but it's not standard procedure for boat wiring. It would be confusing to another person working on your boat or even you if you forgot how you wired it.

different bulbs can change the sector angles...which is what I believe FF is referring to...that's why vessels 20 meters or more shall have screens fitted usually...

5. Screens for sidelights

psneeld said:

different bulbs can change the sector angles...which is what I believe FF is referring to...that's why vessels 20 meters or more shall have screens fitted usually...

5. Screens for sidelights

The sidelights of vessels of 20 meters or more in length shall be fitted with inboard screens painted matt black, and meeting the requirements of Section 9 of this Annex....

ANNEX I: INTERNATIONAL POSITIONING & TECHNICAL DETAILS OF LIGHTS & SHAPES​

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Well based on what he posted: "The Fresnel housing is built for a pinpoint 360 deg source , not for a bunch of LED glued to a stalk."

He seemed to be talking about the way a Fresnel lens focuses light. Not shading the light source.

But, I could be mistaken I guess.

he also used the word filament...

I let him say what he meant then....

Some folks would have you believe that if you have a "Perko" brand navigation or anchor light that it would only be approved if you relamp it with a "Perko" brand lamp, not a Sylvania or GE lamp with the same number. This is absurd.

The people who inspect my boat each year just look to see if the lights work.

rwidman said:

The people who inspect my boat each year just look to see if the lights work.

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What, you mean they don't stand the correct distance away required for each light to be visible from and measure the exact output and angle of visibility of each light!? Slackers!

Injured In A Recreational Boating Accident?|Help from Maritime LawyersLatti & Anderson

Our maritime lawyers have obtained payment for medical bills, past and future pain and suffering, past and future lost wages, impairment of earning capacity and other costs of a recreational boating accident caused by:

• Drunk boating
• Excessive speed
• Lack of or improper navigational lights
• Defective or missing equipment
• Operator error or inexperience of operator
• Hit and run
• Traveling at a high rate of speed
• Producing a wake in a no-wake zone
• Overcrowding
• Collisions with other vessels
• Collisions with rocks, docks, jetties, piers and sandbars
• Operating in poor and/or rough weather conditions

psneeld said:

Injured In A Recreational Boating Accident?|Help from Maritime LawyersLatti & Anderson

Click to expand...

What's your point? Because I don't recall anybody advocating:

"Lack of or improper navigational lights"

And there are LED bulbs that will center on the Fresnel lens like a filament bulb does. Marinebeam makes some as I recall.

psneeld said:

Injured In A Recreational Boating Accident?|Help from Maritime LawyersLatti & Anderson

Our maritime lawyers have obtained payment for medical bills, past and future pain and suffering, past and future lost wages, impairment of earning capacity and other costs of a recreational boating accident caused by:

• Drunk boating
• Excessive speed
• Lack of or improper navigational lights
• Defective or missing equipment
• Operator error or inexperience of operator
• Hit and run
• Traveling at a high rate of speed
• Producing a wake in a no-wake zone
• Overcrowding
• Collisions with other vessels
• Collisions with rocks, docks, jetties, piers and sandbars
• Operating in poor and/or rough weather conditions

Click to expand...

[*]Excessive speed
Reminds me of a conversation we had about running the Jersey ICW at 20-22 knots at night using a spot light to sweep the area in front of said vessel.
It appears this is in direct contradiction of that conversation.
Bill

psneeld said:

Collisions with rocks, docks, jetties, piers and sandbars

Click to expand...

Impossible.

I don't believe there is any legal risk involved if the light can been seen from two miles or more and the intensity is the same whether the lens has a LED bulb behind it or not.

The point is the light mfg PROVED to the USCG the light met the published requirements.

Any replacement bulb with the same US std. numbering would be accepted , however in the superior Euro lights the style needs to be copied as well. A US 1156 is a 1156.

Many better Euro bulbs have a long vertical filament and their wattage is marked on the bulb
So a Bosch light would be legal with an Identical bulb from another MFG.

TO me the hassle would come AFTER a crash ,say a jet skier slams into your stern at 50K some midnight.

The skiers liar for hire may get a court order to inspect your boat , and an UNPROVEN , home brew modification (LED bulb) will be brought up to >prove< your unproven modification was the cause of the accident (not the 2.5 blood alcohol ) and deaths. He will claim it could not be seen in time..

Reality might be your new LED bulb shows for 10 miles instead if 2 , but there is NO legal government proof.

How does one defend that?

The Navigation Rules specify required brightness for each light. Currently, there are no federal or state requirements for boat owners to utilize certified fixtures (fixture and bulb). This is a requirement only for boat manufacturers. So your lights have to be in compliance with the Navigation Rules. A properly constructed LED festoon of the proper color will out perform the filament it replaces and exceed the standard of the Rules.

caltexflanc said:

The Navigation Rules specify required brightness for each light. Currently, there are no federal or state requirements for boat owners to utilize certified fixtures (fixture and bulb). This is a requirement only for boat manufacturers. So your lights have to be in compliance with the Navigation Rules. A properly constructed LED festoon of the proper color will out perform the filament it replaces and exceed the standard of the Rules.

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If not exactly the same shape...that may very well be debatable which is what FF first meant.

Even just a quarter inch difference in a small fixture would change sector angles ...how much depends but a shrewd lawyer is a dangerous opponent.

Heck I know most of you know a lot more than the rest of us...hopefully none of us will never have to prove it either way.

Billylll said:

[*]Excessive speed
Reminds me of a conversation we had about running the Jersey ICW at 20-22 knots at night using a spot light to sweep the area in front of said vessel.
It appears this is in direct contradiction of that conversation.
Bill

Click to expand...

caltexflanc said:

........... A properly constructed LED festoon of the proper color will out perform the filament it replaces and exceed the standard of the Rules.

Click to expand...

Yep.

Some forum members seem to get carried away when it comes to the "regulations" as opposed to the practical implementation of the regulations.

I have converted my navigation lights to LEDs and I believe they are compliant. If at some point some attorney wants to challenge them, I'll let my insurance company worry about it.

The Rules are very specific as to what the lights have to do and where they have to be; you either meet those specs or not. The Rules say nothing about how they are to be constructed. If you are worried about lawyers, worry about the law they will litigate against.