Restoring a Boat Spotlight - need help

[4watt]

I've been searching the web for information on restoring a vintage marine searchlight and this site keeps coming up so I'm hoping someone here is willing to help me figure out what I'm doing. (I've run a few searches on the site and read a bunch of posts but nothing seems to fit what I'm trying to figure out)

It's a 9" brass spotlight similar to the ones made by Perko.

The internals are gone and the convex glass is cracked in half. I'm looking to retrofit a modern reflector and light source into the existing housing.

I looked at the 9" sealed beam replacement sold for the Perko but it costs about $450.00 and would still likely need some fiddling to make it work which takes the joy out of the project.

I found someone who sells a pre-focused reflector and lamp unit but can't tell what the beam would look like or what the quality is.

I also looked at a company that sells reflectors, but don't know how to match a reflector with a lamp and put the whole thing together.

The basic design parameters are:

A tightly focused (collimated) beam with a reach of 1/2 mile (900 yards) or more for spotting buoys and other navigation markers.

To run off a 12 volt DC power supply, 250 watts max continuous current draw,

Preferably an off the shelf bulb that I can get replacements for easily.

Preserving your night vision on the water at night is important and boats are often fitted with red lighting on the bridge because of this so a light source at the warmer end of the spectrum would probably be a plus.

Any advice or links to suppliers would be greatly appreciated.

 

[4watt]

Hi all,

After some more online research I've found the information I needed, and some good sources for components. Of course I'd still value additional input on the subject but for now I think I've got everything I need to complete the project.

~ 4watt

 

[Hoop]

If you are looking for 1/2 mile reach at a maximum of 250 watts, I think your options are: Short Arc, Plasma, or HID. Plasma is easy to get into, as there are development kits available from Luxim, but it will cost about 1k for the bulb and electronics. The output will be in the 23k+ lumens range with the 75 cri version. Short arc is a bit dangerous and will require either purchasing a new ballast from a company such as AElight, or rigging up a projector ballast to work. Rigging the projector ballast will be much cheaper but you will also have to tap into the 300vdc output of a ac/dc inverter. The ballasts from AElight have an inverter built in so they can run on low voltages. They cost up to $1k though. HID (metal halide) will be the cheapest and easiest to implement. Grabbing a 50 watt ballast from TRS and a bulb is as simple as it gets, but I suspect 50 watts isn't going to illuminate too far out on the water.... HID's get a bit more difficult to source parts and to collimate as the wattage increases. AElight has a 200-250 watt HID ballast which I'm sure is also pretty expensive, and they list recommended bulbs for it. It runs on 120v so it will require an inverter but that's inexpensive to acquire. So, if cost is a factor, I'd say give 200-250w HID a shot. It should work well in a reflector approaching 9".

Edit: surfing around the net, it seems higher wattage HID setups are not so hard to source after all. The bulbs and ballasts use a correlating ANSI number so they are easy to match. Ceramic Metal Halide bulbs offer very high CRI ratings and good color temperatures. 150 watt setups are easy to implement and the bulbs are small. Example: 150 CMH bulb and ballast.

 

[4watt]

Thank you Hoop, not only for the wealth of information but for making it so clear and organized. (I really appreciate it when people go to the trouble of pasting links into their posts)

After saying that I need a reach of 1/2 mile and seeing from your post that it really takes some serious gear to get that kind of output, it occurs to me that the marine spotlight industry may be overly optimistic when they rate rate the "reach" of their searchlights.

I'm in awe of the plasma and short arc, but also trying to do this on the cheap. The HID bulb & ballast at 10,000 bulbs you linked to are within my budget and are the first a la cart components I've seen that I can understand how to use. Thanks. I found this company that makes reflectors: http://www.phoenixelectroforms.com/ They make some 9" ones and quite a range of focal lengths so I may be able to get one that works with that bulb. The housing for my searchlight is pretty roomy so I can probably fit the transformer inside it.

So far the best solution I'd come up with was to buy a Lightforce 9" halogen driving light: http://www.lightforceusa.com/products/240-blitz and kit-bash it to use in my spotlight "shell". The size of the reflector is almost perfect, it has the front lens, and I can be pretty sure that they have the optics/focus set up correctly. One of the other attractions for me is that they sell a HID kit for it so I can get on with the project for $150 now and then upgrade to HID later on.