posted 06-13-2000 12:41 AM ET (US)
The electrical "panel" on my boat is home made and quite compact. Here is how it works:At the battery, a waterproofed in-line fuse (20A) protects the positive lead, no fuse in the negative lead.
From the battery a length of 12ga. red/black cable under white cover runs along the side of the boat, along with the engine remote cable, the shift cables, and the steering cable, under the console and terminates at a terminal block with about 6-8 rows of terminals, each with two screws. Little jumper clips mulitply the postive and negative battery connections so there are two or more rows of the raw battery postive and negative.
The VHF Radio and the Depthsounder are connected directly to the battery terminals here; each of these has its own ON/OFF switch built into it. The radio has its own in-line fuse; I think the depthsounder does, too.
A dashboard mounted switch controls the running lights, with a 14 ga. Red/Black under while cover cable running back to the stern where it connects to the running lights terminal block (OEM) on the port stern wall of the cockpit. The running light circuit also feeds the tachometer lighting circuit, so it is illuminated whenever the running lights are on. There is an in-line fuse protecting this circuit. It is installed between the battery positive at the dash terminal block and the switch. This is fused at about 5A so that it will blow before the main 20A, should something short circuit in the running light circuit. The main fuse wont be tripped.
I used the WEST Marine Ancor brand cable for these runs; it is nice cable and quite flexible.
The GPS runs off its own AA Batteries, as this is simple and I have basically an infinite supply of slightly used AA batteries. Isolating the GPS receiver from the battery on the boat prevents any problems with alternator/magneto whine getting into the radio and causing interference.
The radio antenna mounting has been a problem! I have a low-cost 8-foot VHF marine band antenna which I leave lying along side the railing and the seat risers on the starboard side of the boat. Lying down like that it doesn't work as well as standing up, but it usually gets the weather stations just fine. I can also transmit on it like that for calling the marina from a short distance or another boat nearby. When it is down like that I use only 1 Watt (LO) of power.
If I were miles offshore and needed to raise someone on the radio, I would just fish the antenna out of the slot along the side of the boat and hold it up by hand to get better results.
Before I had the bimini installed, I used to use a little piece of wood with a mount attached to it which I would C-Clamp to the seat. This worked fine, but now with the bimini top installed and up, you cannot mount the antenna base at either seat and get a clear shot up--the top interferes.
So I am still looking for the perfect place to locate the antenna mount. Only the transom looks likely, but I don't want four extra holes in it.
I have been thinking about developing my own compact antenna which would mount on the top of the outboard motor cowling (metal!). The flat top of the outboad is really about the best ground plane on the boat (all fiberglass otherwise).
Another idea I have had involves using the stern light pole as part of the antenna.
By the way, I have quite a bit of experience with antennas and transmitters, having worked as a Broadcast Engineer for over 25 years, and prior to that I was Associate Editor for a rather well-regarded radio techincal journal. Antennas have always been a topic of intense interest to me.
All the "gain" of any antenna comes from compressing the radiation into narrower beams, but at sea the motion on a boat can produce a situation where really high gain antennas don't result in improved transmission or reception. The narrow beam of the antenna is rocked up and down by the boat's motion.
So I am not a fan of really long, high-gain antennas for boats.
--jimh