Sooner or later, you will want to install a connector on your boat. But which kind to use? In this section, I'll describe three options, in ascending quality and price. The first type; the Molex 093 Power connector is actually quite common on boats, and is suitable for non-wet areas. Unfortunately, the definition of non-wet varies between boat manufacturers as I have seen these in areas they should not belong. The second type; the Metri-Pack is an automotive-grade connector, and is not as common on boats, but you may find them in the engine's wiring harness. The last type; CPC (Circular Plastic Connectors) are the best (and most expensive) of the three, and are typically found on the back of all those navigation and electronics devices on your boat.
In all cases, the connector parts must all be ordered individually. Typically, you have to order the mating plug and socket, as well as the male and female pins separately. One exception for the Molex connectors is that Radio Shack usually stocks a limited variety of connectors, and you typically get both housings, as well as the male and female pins.
Pins are available as crimp or solder, and usually in tin or gold plating. For the Metri-pack connectors, and especially the CPC connectors, it may actually be quite a lengthy process to figure out all of the part numbers you need for each connector.
All of the connectors are available from the more popular electronics retailers, such as Allied Electronics, Digi-Key, and Mouser. However, I would recommend purchasing from Mouser - especially the CPC and Metri-pack connectors as Mouser has extensive documentation, data sheets, and assembly instructions. And unless you intend to solder the connector pins, you will have to invest in a crimping tool, and possibly a pin-extractor.
Molex 093 Power Connectors
The molex connectors are farily common in the boat industry, and are the least expensive and easiest to work with. Their chief disadvantage is they are not waterproof, and the pins can slip out of the connectors. I had a starting problem in one of my previous boats that I traced to a Molex connector pin not pushed all of the way in. It was likely this way from the factory, and when I disturbed the connector the boat would not start until I reseated the connector.
Connectors are available for two to 15 pins, and expect to pay $3 to $5 for a complete connector and pins, depending on how many wires are needed. Generally only crimp terminals are available, but you can solder the ends of the terminals if you are careful. Generally the pins are interchangeable, so that either male or female (or a combination) will fit in either male or female connector body.
Delphi Metri-pack 150 (automotive) Connectors
These connectors are popular in the automotive industry, and are a good choice for an inexpensive waterproof connector. Connectors are typically available from 1 to 12 pins, and expect to pay from $10 to $15 for a complete connector and pins, again, depending on how many wires are needed.
The male and female terminals are not interchangeable, and will only fit in their corresponding body. As well, the connectors are a bit difficult to assemble, and if not correctly assembled, may not work properly.
These are commercial grade versions of high quality military-specification connectors, and offer the best in waterproofing. They are available in almost unlimitless configurations, such as standard and reverse sex orientations, differernt pin sizes (and current carrying capability), various rotational indexing, screw on or twist on threads, choices in cable clamps such as right-angle, straight, and heat shrink versions; pins include tin and gold plating, and either solder or crimp on. Some research is required to obtain the correct connector, due to all of the options. Connectors are typically available from 1 to 20 or more pins, and can cost from $10 to $40 or more for a complete connector, pins, and cable clamp. True mil-spec connectors with metal housings can be double to triple that cost. Therefore, these are usually suited for the most demanding environments.
Molex 093 Power Connectors
Amp/Tyco Circular Plastic Connectors (CPC)