Underwater Lights that screw into through hull

[zboss]

I know underwater lights are an unpopular feature... however just hear me through on this.

We have two existing 1/2" through hulls for our propane locker. However, these are not in an optimal location and generally speaking are at or below the waterline. Obviously, this is not a great situation and I would like to move those thru-hulls up so they are never underwater. Please no lectures on how I'm going to blow my boat up... I didn't design the thing and I am correcting it. I was surprised the surveyor did not note this issue and we didn't discover it until much later when the boat was loaded for cruising.

Anyhow, I want to repurpose the existing through hull for underwater lights but not take out the seacock and through-hull. My ideal light would simply screw in where the mushroom head is currently. The seacock would remain in place and open with the wire going through the seacock and into the back of the light. In an emergency situation, the wire could be pulled free of the light and the seacock closed.

Does anyone make something like this?

Thanks,

z

[Pete7]

How are you going to stop nasty things growing all over it, especially if it is close to the water line so lots of sunshine.

Pete

[David M]

I don't have an answer for you but am wondering the purpose. For attracting bait fish?

[wingless]

The seacock has NPS (straight) threads for the thru hull fitting.

It would be possible to cast then machine a bronze part w/ NPS threads to screw into the seacock. That new bronze part could have a plate that accepts a standard underwater light, like my Lumitec SeaBlazeX.

There are several issues w/ this plan.

1. The seacock ball is not a wire cutter. It would need to chop the LED wires for the plan to work.
2. Anything custom, non-standard, that could potentially fail, causing water intrusion and the associated damage loss, could be reason for the insurance company to deny a claim.

If underwater light(s) are desired, then do the correct steps to ensure problems are prevented.

[darylat8750]

Not something I would want but it should be able to be done safely.

So you put push on electrical connections on the back of the light fixture so like you said "In an emergency situation, the wire could be pulled free of the light and the seacock closed. " I would also run the wire inside a below the waterline rated hose that terminates and is secured well above the heeled waterline. Glue the fixture in the sea cock from the outside using epoxy putty or ? Be sure to keep the epoxy or 5200 or whatever you use well clear of the valve.

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[zboss]

No... the quick-release wires would pull out of the back of the light and be pulled into the boat, leaving the light with no wires attached. Then the seacock closed. Being that there are a lot of lights on the bottom of boats right now that do NOT have a seacock, it seems like a better idea.

The lights are undoubtedly cool looking. Plus, they do bring in big fish at night, so it would be fun for adults and children alike. Namely me while diving and snorkeling at night. I want them to pulse to the music like the Puerto Ricans do

My alternative is simply closing the seacock as I am certainly not going to go through the trouble of filing in a 2 inch thick hole in the hull.... so I'm not seeing any down side to the idea. Except of course the availability of said lights.

[RKsailsolo]

So what's wrong with underwater lighting in the first place? (Apologies for my naïveté). Is it the failure risk?

[zboss]

Originally Posted by RKsailsolo

So what's wrong with underwater lighting in the first place? (Apologies for my naïveté). Is it the failure risk?

Its another hole in the boat. Less holes are usually considered better. Lots of guys go out of their way to reduce the amount of holes below the waterline and even go to great lengths to remove ALL below the waterline holes.

Being that almost all my seacocks are at or a few feet below the waterline I had gone and replaced all the seacocks with more robust versions before I knew enough to think about actually moving them up, which would be very difficult and expensive on our CR for all but a few.

Personally, I think lights are very cool. Great for fishing, a blast when you are swimming and diving. There is nothing like waiting out your 5-10 minutes on your anchor after a night dive with all sorts of large fishes and eels swimming by to check out the lights. We will probably just get a few to hang overboard instead.

[Doug4bass]

Our new C-385 was delivered with a Dr Led though-hull GREEN led light....just ahead of the rudder post. Pretty cool.
The actual light is removable while the boat is in the water....similar to a speed transducer. So far, so good...although
i have heard mixed reviews on the good Doctors products and customer service. You want GREEN imho.

[Palarran]

I think below water lights are pretty cool but wouldn't go about it as you are suggesting. It would be much better to just pull out the whole assembly and put a properly designed underwater light in. They are primarily designed for high speed power boats so IMO should be able to take whatever you can dish on a sailboat. Dang things are expensive though.

[mitiempo]

Originally Posted by Palarran

Dang things are expensive though.

Like the Lumitec Seablaze at about $300 each.

I also would not mickey mouse the installation - remove the through hulls, enlarge the holes as necessary and install them properly.

As cool as they are they are at the bottom of the list for what I would spend that much money on.

[cal40john]

ABYC only says above the waterline. It does not specify above heeled waterline. I've found a couple of sources that say static waterline. I assume that they think the waterflow and turbulance is sufficient to carry away the propane under sail. So unless the through hull is below static waterline you don't have to move it.

[mitiempo]

If the vent is below the heeled waterline it is below the waterline.

[Overlord]

I have just sailed 20 000 miles as live aboards on our catamaran. I cut two 4 inch holes in the bottom of my hulls , with a smile on my face....why ? because i did it myself and i did it properly , just a bit of epoxy paste and 5200. Let the armchair naysayers say what they like. They are easy to clean , and every sailor should be able to go over the side to check his hull. They provided us with hours of entertainment , in the Bahamas , Cuba , San Blas , and right through the pacific. I used lumitec Seablaze 3 @ 199$ each.
I would not use your mushroom fittings but fit them as directed
My 2c , sorry armchair chaps

[cal40john]

Originally Posted by mitiempo

If the vent is below the heeled waterline it is below the waterline.

A couple of marine surveyors and a Practical Sailor article say static is what is called for. The PS article does say in a picture caption "should" be above heeled waterline.

Safe Boat Propane System Installation

LP Gas Systems Part 1: Installation and Safety | | PassageMaker

Some Propane Dos and Don’ts - Practical Sailor Article

Safety creep. I've heard 5, 10, 15 minutes and a half hour is the time needed to safely pressure test your propane system. ABYC calls for only 3 minutes.

If you want to go beyond what ABYC calls for that's great. I find most of their rules a bit overboard to begin with.