Rewiring a Classic Mako

Hello,

I have been overhauling an old Mako getting it seaworthy and the project is at the rewiring stage. The attached diagram details how I plan to rig everything. I have seen a lot of people lend a hand and knowledge to help others on here. Thanks in advance for those who share their thoughts.

A little history about the boat & project:
The vessel is a 1976 Mako Offshore original came with twin gas screws
Centerline Length 26' • Beam 9'-6" • Hull Draft 22" • Full Transom • 6500 lbs (unsure if it includes the weight of the old engines)

I had several engines over the past 2 years that could have been in the boat including two old 453 Detroit Diesels and in the end I divided on a 7.3 idi International. Not a common marine engine but I have a good feeling about it. Some specs for that:
3,400 Max RPM • 185 HP @ 3,000 RPM • 920 lbs • 360 lb-ft Torque @ 1,400 RPM

I know many other engine could have been a better match and my top speed wont be 70 knots but its what my budget and resources allowed. I dont care for speed or bragging rights. Best part about this is that its a father, son project and I will get to enjoy this boat with my dad.

A small gallery with images of the project so far.
http://www.flickr.com//photos/46855187@N05/sets/72157629738364844/show/

Some of the parts I will be using:
http://www.iboats.com/Dual-Battery-...0410565--session_id.892115239--view_id.341114
http://www.bepmarine.com/media/product/pro4cd730f0a9bf4.pdf
http://www.iboats.com/Screw-Termina...0410565--session_id.892115239--view_id.163741

All nav & courtesy lights will be LED

Thanks to everyone in advance.

 

Way cool, not many inboard Mako's around. It looks like you have everything pretty well in hand and in the Miami area there are certainly plenty of good craftsmen to call on.

Re wiring, I'm sure you know this but be sure to use tinned wire of an appropriate gauge. I would also suggest solder and heat shrink all connections.

You may or my not want to look up the ABYC standardized wire color scheme, tracking down all the various colors and stripes might cause you to compromise on wire quality.

Steve just North in Ft Lauderdale

 

You should be able to match the ABYC color standards with good quality wire - Ancor and others make marine wire in all colors and sizes - please use the guidelines - you will be much happier next month when you make a change or need to do some troubleshooting or if someone else helps.

Also - please mark the ends of the wire with numbers (and have the numbers on the wiring diagram) - not many recreational boats seem to have the numbering and diagram but you will save a lot of trouble and hassle if you ever need to do any work on the wiring or troubleshooting.

 

Did the 7.3 engine came from a pickup or a industrial engine.? It matters because pickup engine has many electronics to deal with. I have a powerstroke 7.3 and the computers on it are pretty well part of it. Great engine and power can well be increased to well over 500hp.

But you may have non-turbo industrial engine with no computer.

 

That's correct I have a 1994 7.3L IDI not the later Powerstroke version. Only electronics on it are power to the fuel pump, the glo plugs and starter solenoid. Rest of the cables are oil, temp & tach senders. The engine was always in a boat and was removed to upgrade. I have looked around and there are some turbo kits for it that bump it from 185 hp @ 3,000 RPM to 190hp. Not sure if its worth the trouble.

Here is a short video of the engine running after running some cooling lines
http://youtu.be/R8KRGz8ixNk

I have tried looking for information on marinized versions of this engine and there was a company called Star Power that did them for a short time period. The exhaust manifolds are SS and look like one-offs made for the previous owner.

 

kOOL, I love that engine. Upgrading to turbo for 5 hp not worth it. Powrstroke has hydraulic powered fuel injectors, what is yours using? Very reliable engine. The one on my truck has 400k and seems to never want to die. I thought about putting some boats but could find any parts to marinize so decide against it. Your engine has manifold now, are those still good?

 

Classic Mako Rewiring Diagram Critique

Can anyone critique the wiring diagram and give your two cents. I designed it based on research from books recommended through out this forum (mainly the Powerboater's Guide to Electrical Systems by Ed Sherman). I have no actual training or experience in marine electrical systems. My main concern is actually the charging circuit.

Is the VSR battery cluster sufficient or do I need a battery isolator?

I am a web designer by trade and am willing to trade services or pay thru paypal, for someone knowledgeable to help solidify my concept.

Anyone want a new avatar or a name decal designed for your boat, maybe some web work? Thats what I can offer.

http://www.boatdesign.net/forums/at...81445-rewiring-classic-mako-wiring-digram.jpg

Thanks

 

I am local in Miami if you want to get together. It seems you are using two banks of parallel batteries. Not sure how you are charging house batteries, and with 4 batteries your going to need more than one alternator.

 

The circuit diagram is a bit difficult to understand because of the weird colors and the missing wiring between between the 4 squares that represent the battery switch (I guess...). I suggest you use different colors for the actual wiring.

Some flaws:

*The auto bilge pump circuit has no circuit breaker. That may prove to be an expensive omission if a pump shorts out with nobody around.

*A push button for the glow plugs is not the way to go. This is a very high current circuit that cannot be fed from the ignition switch; there should be a power relay and a temp controlled timer between the push button and the plugs, with a direct feed from the starter battery.

*There should also be a fuse or circuit breaker between the ignition switch B contact and the instrument panel. The panel wiring should include a few sockets for additional devices like a depth sounder or GPS.

*Like mydauphin wrote, one alternator for 4 batteries is a bit meager, unless it is a very big one.

 

Awsome feedback so far. Thank you all.

Thank you all for your comments

CDK I am going to rework the diagram an repost.

• Regarding the 4 batteries and one alternator, I did not calculate amp hours and what my application requires. My father is always concerned with conserving battery power on our current small boat. I wanted to have sufficient power to keep all loads on through a night of fishing and have enough juice to crank a cold diesel.

• All lamps will be led maybe I don't need 2 for the house load Ill have to calculate the amp hours I need.

• The engine has a glow plug controller that is not in the diagram that basically does everything you detailed. Ill will include that in the reworked diagram.

Thanks again

 

You also don't mention what type of use you are going to be giving boat. Extended anchoring with a radio/ amplifier or cruising, fishing. All put different loads on system. Unless you have big loads, 2 batteries are find. Use one to start engine and run to fishing spot, and one for house. You switch to house battery on way home to charge it. But then we don't know who your going to use boat.

 

Re the bilge pumps. Fairly typical is one bilge pump run direct off the battery no fuse no breaker no nothing. It should have it's float set a bit higher than the others. ABYC condones this is my understanding but perhaps some of the pros will comment. I have four circuits (three fused) hooked to the batts that don't go through the A B Switch. Stereo memory, security, shower sump pump ( because I hate forgetting to turn it on ), and bilge #1. You may not want to "advertise" the macerator pump also. If you have an electric anchor windlass you might want to run that by us as well.

edit... One other thing. Soldering was mentioned. I don't pretent to understand why, but ABYC frowns upon soldering. Use one of the aproved connection methods.

 

If the macerator pump discharges overboard then it needs to be able to be locked out to meet Coast Guard and many state standards for no sewage discharge.

My understanding on the "no solder" is that there is a hard spot at the end of the solder and start of the non-soldered area - flexing this area can cause the wire to break (solder is not permitted in aircraft for the same reason) - a proper crimp will give a good connection with all the air crushed out and the wire strands forming basically a solid hunk of metal.

Many people do both crimp and a bit of solder then add shrink wrap to keep the area at the end of the solder from flexing and to make sure there is a solid electrical connection - they also support the wires so the flexing of the joint is minimized.

You want to buy a high quality crimper that is designed for the connectors you are using - also give the connection a good pull (there are standards for the minimum pull) to make sure the connector is firmly attached. Don't even think about the cheap crimper from the hardware section of the drug store. I have one of the ratchet ones from Ancor that is designed for their tinned and insulated fitting.

If the connections are not done properly you will get a connection or crimp that will deteriorate over time and you will get a high resistance area that can get hot and then the equipment might not work and in the worst case things can get hot enough to start a fire - not good at all - I have seen several fires and almost fires from connections that deteriorated over time.

As a regular check thing - check the screws once in a while on the terminal strips etc to make sure they have not backed off.

 

The typical bilge pump is a plastic housing containing a cheap electric motor, separated from the liquids around it by a tiny seal around the shaft and a compression seal around the cable. It is not difficult to imagine that given enough time, the construction will fail. Water will enter the motor chamber, rust will fill up the gap between rotor and magnets and a potentially dangerous short circuit is borne. A small obstacle like a pin or screw blocking the impeller can have the same effect.

In my opinion it is a mistake to omit a fuse on a circuit that is bound to fail sooner or later, unless the bilge pump is replaced each season (nobody does that I guess).
In my own boat I use a contactless float and a small electronic circuit in a sealed housing attached to the transom. The circuit keeps the pump running for an additional 10 seconds after the float wants to shut it off. That has two advantages: the pump spends its days in much less water and it doesn't run as often as pumps with only a float.

 

I was assuming from diagram that those things that look like switches were breakers. If not they really should be, a 50 amp breakers should not be your only protection. And yes bilge pumps do need their breakers or fuses. I am glad to see your providing for 3 bilge pumps. So you should have three circuits/fuses.