I completed the installation of Halogen lights in Hull #179. I will provide the benefit of my work.
Ray Stone, Pro Tem Duo, #179

First there are at least four different makes of Halogen puck lights. I have some old models that I used under shelves in cabinets in our home. They have been satisfactory for that type of installation. They are 12 volt, 10 watt with transformer but they can only be surface mounted, which would block the door over the dry storage. Also, a very small screw had to be removed to change the bulb.

Another brand is Hampton or Hampton Beach, which is a ceiling fan company. They look very much like the other brands but are all white without the center black ring. These units use 12 volt, 20 watt bulbs but do not have a transformer. Instead they use a dropping resistor or diode and plug directly in 120 volts. This is not suitable for a boat. Furthermore, the diameter of the housing is 2-3/8 inches, much too large to be flush mounted and because of the voltage-dropping device a great deal of heat is generated.

A third brand is distributed by IDC made in China. These are white with a black center ring. They are 12 volt, 10 watt with transformer and can be flush mounted. Just right for a boat, except the diameter of the housing is 2-3/8 inches with the mounting screws within the circumference of the housing making it too large and difficult to hold in place.

The best brand is one that has been carried by Home Depot and Home Base. The brand is USA or LUSA made in China. They are white with a black center ring and can be flush mounted. They are 12 volt, 20 watt and have a transformer. These units are only 2-1/6 inches in diameter.

The holes in my overhead liner were 2 inches in diameter and needed to be enlarged. I made a jig using a 2-1/8 inch hole saw. To center the saw in the center of the opening I drilled a plug out of 1/4 inch Corian plastic using the 2-1/8 inch hole saw. This gave me a plug 1/4 inch thick and 2 inches in diameter, just right. I put spacers inside the hole saw so the plug protruded out of the cavity of the saw about 3/16 inch. This jig was used to center the saw cutting the hole 1/8 inch larger. It took less the a minute to enlarge each hole. The light housing fit snugly into to the hole. Another advantage of this brand is that the housing has two plastic tabs that protrude from the housing. These held the unit in the hole so snugly that I didn’t need to use screws to hold it in place. I saved the screws in case the housing ever came loose. I replaced the bulbs with 10 watt except the one over the refrigerator.

I believe both Home Depot and Home Base are discontinuing this brand so if you want to retrofit I suggest you see if there are still some on the display racks. I did not replace the two lights over the dining table. The Halogen lights are more like a spot light rather than flood. They are very suitable for reading but I feel that the incandescent lights give a softer lighting for dining.