Boat electrical wiring/Fuseblock/Circuit Breakers help needed.

I own an 18 foot 1975 Starbuck jet boat. It is powered by a Chevy 402 Big Block motor that was bored out 40 over and now has approximately 410 cubic inches and has a Berkeley 12JC jet pump for propulsion. My motor has 10.5 to 1 Keith Black pistons, Eagle H racing rods, 3/4 race Cam Dynamics Hydraulic cam, Edelbrock RPM manifold, Holley 750 double pumper. The motor is balanced and was machine to withstand sustained 6000 RPMs the motor has about 3 hours of run time on the fresh block, that I installed into the boat in the late spring of 2010 myself.
I need to completely rewire my boat due to a short in the electric wiring in the starter area and also along the starboard gunnel where wires travel to the engine bay from the dashboard area. I want to replace all the existing wires with Marine type tinned wire for boats in the correct marine wiring colors. My existing wiring does not appear to be fused anywhere that I can see, so I am in the process of trying to figure out a solution for adding a fuse block and circuit breaker option near the battery into the new wiring to the dashboard area. I have purchased a Perko on off switch I plan to add to the wiring from the battery catalog # 9601, and a Marine one wire alternator 105 AMP for safety reasons. My boat has dual saddle tanks, next to the engine/starter/alternator and wanted to eliminate the possibility of sparks flying around for safety which is the reason I bought the marine alternator.

I recently purchased "The 12 volt bible for boats", however I still have electrical questions even after reading this, and hope someone can help me out with good advice.

I am using a bilge pump, a fuel selector solenoid to select right or left gas tank from dashboard switch. I have the following in the dash for gauges: Water temp, voltage gauge, (one fuel gauge for dual tanks - selector switch switches between tanks and tank sending units), tachometer, (oil pressure gauge that is mechanical - it has a hard tube line from the engine that contains oil running into the back of the gauge).
These gauges are currently not hooked up for any lights and I am planning on hooking up a navigation light, and an anchor light with switch to the dash. I would also like to hook up the gauges so they are visible at night, since the option seems to be available for this in each gauge.

I would like to add a 12 volt accessory plug in the dash for a spot light.
I am not installing a stereo so I would not have to figure in anything volts or AMP wise for that option. After all it's a speed boat and the only reason I want to add any lighting is in case I decide to stay on the lake past dusk, so I don't get a ticket from "the man" on the lake (water patrol).

Question #1: What size inline circuit breaker would be recommended from the battery to a fuse block up under the dashboard? - I am going to run #6 AWG marine grade red wire from the battery area to dash board area for a Constant Hot wiring source, I will be adding a bus bar so this wire will connect to bus bar under the dash. This would then be used to power the key switch for the constant hot. The purple wire for the ignition on coming from the key switch would go to the fuse block to supply 12 volt power for the dash lights, the ignition to the coil, the bildge pump, navigation lighting. I want these fused for protection. The start wire on the key switch would run separately back to the starter solinoid. - Yellow with red stripe.

Question #2: With the size of my engine and the accessories listed, what would you recommend for a fuse block up under the dash board? How many AMP total rating?

Question #3: How many circuits in the new fuse block would I need to get? and how many AMP maximum for each circuit should I be looking for?

Any help you give me would be really appreciated, the local boat shops/marina's here in Missouri WILL NOT work on jet boats, or give ANY advice, so I have to perform all the work myself without direction...which really sucks. While this is a major undertaking, it is not rocket science. I plan to do the work myself, since it is my only option, and plan to make a wiring diagram prior to starting any of the work. I have been able to find a few diagrams for wire routing, but these do not really contain all the information about fuse blocks, and circuit breakers so I need to find out what to do before I start buying stuff that won't help me, or cause a fire because I didn't do it right. I do know that when figuring wire size, you have to double the distance from battery because it is a circuit and is a round trip lenght I have to figure and have to know the AMP on the line to figure the correct marine wire sizes.

Hope someboady can help me with this project before spring is here in 2011.
Thanks for your time,
mikes402jetboat - my boat can be seen at screamandfly.com in my albums and my loggon name is the same at screamandfly.com - mikes402jetboat

If you're gonna run a red #6, don't forget to run a black one too. The electric loads need a complete path to and from the battery, so try to match the size on the positive and negative wires.

As far as the fuse for your "main" line, The big load will be the starter's solenoid. If you have a slave solenoid, 5 amps should cover it, if no slave, you'll need at least 25 amps. You can always measure if in doubt. The other significant item is the ignition. unlike the starter, it's load will be continuous with the engine running. Some hi-perf ignitions (MSD) can draw many amps.

The thing to do is write a list of everything that you will supply in your system, find its current requirements, and add them up. A table like that mmakes a great addition to your circuit diagram, too. Then break the list into groups - some, like the ignition, will be in their group solo. assing a fuse to each group and that's the minimum number of fuses you'll need. Be wise to plan on growth - I'd say two fuses min....you never know. From there it should be straight forward.

One other thing - adhesive lined shrink tubing and a can of liquid neoprene. It isn't much more money and it will make the boat wiring last for decades to come. Another good practice is to run the wires in the convoluted tubing commmonly known as loom. and secure it every 18-24 inches with a clamp or a tywrap with an eye....makes for a professional finish.