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Author Topic:   Wiring VHF in new Montauk
MickP posted 05-13-2005 06:27 PM ET (US)   Profile for MickP   Send Email to MickP  
Finally took delivery of my new Montauk:-) I'am installing a Icom 502 have it mounted in the dash, would like to know were to hook up the red wire and the red and black wire should I go to the battery or switch (if hooking to battery red to positive red and black to negative????) if going to switch can anyone tell me exactly were these wires go I have very little knowledge on the proper wiring, any and all directions greatly appreciated.
Thanks for the help!
Maximus posted 05-13-2005 07:52 PM ET (US)     Profile for Maximus  Send Email to Maximus     
I recommend you do some planning. This will probably not be the last accessory you add. Install two new ground and one power (the factory wiring includes a separate ground bus, but IIRC there was not additional room.)

As for wiring, I run my VHF through the ACC switch. Typically, Red is power (12volts) and black is ground. A test light or volt meter will tell you which post to pull power from on the ACC switch (it should be a post with nothing attached). I found it easier to remove the ~8 screws that hold the dash plate to the console and work from outside.

This is a great time to install an hour meter.

jimh posted 05-14-2005 01:10 AM ET (US)     Profile for jimh  Send Email to jimh     
In 12-volt DC wiring, RED is almost always positive and BLACK is almost always negative. However, it pays to verify things like that before connecting devices.

I do not see any value in wiring the power to the radio through a dashboard mounted switch. The radio has a power ON/OFF switch itself which should be sufficient. My preference is to wire all loads downstream of the master ON/OFF switch on the boat. This way, when that switch is in the OFF position, there truly is nothing connected to the battery, and because of that philosophy I do not recommend wiring the radio directly to the battery.

Most devices like a VHF radio will have their own in-line fuse, so they do not need to wired to a circuit breaker on the power distribution panel. They can be connected to the power distribution bus. I am fairly confident that Boston Whaler provided such a connection point for you.

From the questions being asked, I would recommend you visit the local public library and check out a book on simple DC wiring and electricity. A well written and illustrated text book can teach you far more about this topic than dozens of replies to your questions in a forum might be able to accomplish.

erik selis posted 05-14-2005 01:53 AM ET (US)     Profile for erik selis  Send Email to erik selis     

Congrats with your new boat!

I agree with Maximus to do some planning for the future and install a new ground bus and power bus. Finding a ground connection is not much of a problem but finding an easy positive (+) connection isn't easy. Bring these new busses to an easily accessible place inside the console so future connections will be a piece of cake. Do as Jimh says and connect the power bus downstream of the main power switch. Almost all external devices are delivered with inline fuses so the power can be connected to this power bus.

Here's a wiring diagram of your boat. You will find a ground bus but no power bus.


walf posted 05-14-2005 04:50 AM ET (US)     Profile for walf  Send Email to walf     
can you install a dual common bus or do you need separate positive and negative bus bars. also where is "downstream' of the master on-off switch?
Maximus posted 05-14-2005 07:33 AM ET (US)     Profile for Maximus  Send Email to Maximus     
The Montauk does not come with a master On/Off switch. My recommendation regarding wiring a bus bar through the ACC switch is simple. It allows you to quickly turn off all your accessories in one motion and to be sure that everything is off with one switch.

A master switch kills everything - including the bilge pump - for some people that works.

The VHF should have inline fuse as well (also this should be the tip off as to which line is positive). Having the radio supplied fuse and the ACC circuit breaker in series causes no issues.

Liteamorn posted 05-14-2005 07:37 AM ET (US)     Profile for Liteamorn  Send Email to Liteamorn     
Again, PLAN AHEAD. If you are going to put dual batteries on board , instead of an on/off switch you can install a battery selector switch,and never play with that switch once you have it on, it would even be better to intall that second battery now (if that is your intentions).
jimh posted 05-14-2005 11:30 AM ET (US)     Profile for jimh  Send Email to jimh     
Walf, you ask:

"where is 'downstream' of the master on-off switch?"

When speaking of electrical circuits, "downstream" means the same as it does in the flow of a current of water, that is, it means downstream in the flow of an electrical current. Also see:

Dick posted 05-14-2005 07:59 PM ET (US)     Profile for Dick  Send Email to Dick     
On my Montauk I wired the VHF, GPS and Fish Fider through the Acc switch. Nice being able to throw one switch and know that all accessories are off.
jimh posted 05-14-2005 11:28 PM ET (US)     Profile for jimh  Send Email to jimh     
I didn't realize that on a stock 170 MONTAUK there is no master battery switch. That would be the first thing I would add.

If there is no master battery switch, it probably is a good idea to group all the electronic accessories onto a single switch. It sure beats a dead battery if you leave something turned on for a couple of weeks.

erik selis posted 05-15-2005 04:51 AM ET (US)     Profile for erik selis  Send Email to erik selis     
I missed something.

I have never seen a 170 Montauk without a main battery switch. Looking closer at the drawing I posted above, I now see it is a CE-option. I'm amazed they don't put it in all the 170 Montauks. Well I guess some CE-regulations do make sense.


jimh posted 05-15-2005 10:08 AM ET (US)     Profile for jimh  Send Email to jimh     
A couple of more comments on this topic:

--First, I think it is wonderful that you can get the wiring diagram for a Boston Whaler 170 MONTAUK from the company via a website. This is terrific use of the world wide web. I have to wonder how many other boat builders have the complete schematic diagram for their boats available on the internet? A tip of the hat to Boston Whaler for providing the resource. And thanks to Erik for digging up the hyperlink to the document, too.

--Second, I love the fact that the diagram is in the PDF format. This means practically everyone on the planet already has the software needed to view it. Also, printing it out provides a very high resolution drawing which is much easier to read than viewing it via a low-resolution monitor. I printed it out and studied it for a few minutes.

--Looking at the schematic, I see that the using the ACCESSORY switch as source of the 12-volts for the radio is probably not the best idea. According to the diagram, the ACCESSORY switch is fused at 5-amperes. A 25-Watt VHF Marine radio may draw more current than 5-amperes when in the transmit mode. For example, an ICOM M-502 is rated at 6.5 amperes in transmit. ( ). The fuse rating may need to be increased. It would be a shame to have your radio go dead from a blown fuse in some distress situation! A simple solution would be to increase the rating of the fuse feeding the ACCESSORY switch to 10-Amperes, if the current rating of switch is sufficient. The wiring associated with this is apparently AWG-14 size. (I infer that from the labeling convention used in the drawing.) That would be adequate for 10-amperes of current.

Also, if other electronic accessories are wired to the ACCESSORY switch, their current drain would also affect the fuse, so, again, using a 5-Ampere fuse is probably not the best way choice for the circuit feeding the radio.

--The HORN is fused at 10-amperes. I wonder what the actual load of the horn really is. If the horn really consumes 120-watts of power and converts most of that into acoustic energy, it is going to be one darn loud horn!

--The wiring in the console switch panel is joined to the rest of the wiring in the console via a connector. (We use the word "connector-ized" in the electronics business.) Having a connector in any electrical current path tends to increase the risk of failure, or at least increase it with respect to the risk associated with having just a direct, continuous wire between two points in a circuit. The connector is used in this application because it greatly facilitates the manufacture of the boat. The switch panel and all of its wiring can be built as a sub-assembly. It can then be installed in the boat and joined to the rest of the wiring via a connector. This is a plus for the manufacturer, but for the user it is a bit of a minus. You will want to be very fussy about that connector, particularly in a marine application where it is going to be in a wet and even salt-water environment. What type of connector is used here?

Knot at Work posted 05-15-2005 03:18 PM ET (US)     Profile for Knot at Work  Send Email to Knot at Work     

the horn on the 170 Montauk IS loud. It sounds like a pissed off, angry Duck.

TampaDave posted 05-15-2005 04:30 PM ET (US)     Profile for TampaDave  Send Email to TampaDave     
Do you have a stereo? If not, your boat is pre-wired for stereo, and if you want, you can wire your VHF into the stereo button. There are two sets of speaker wires, a red/black pair, and the mysterious yellow wire (which doesn't connect to anything) all in one bundle. Can't miss it.
timsr posted 05-15-2005 05:17 PM ET (US)     Profile for timsr  Send Email to timsr     
Why couldn't you just wire the VHF directly to the battery since it will have it's own inline fuse and On/Off switch.

Jim's suggestion on just replacing the ACC fuse with one of larger amperage sounds reasonable I just wonder why BW only put a 5 amp fuse there.

Liteamorn posted 05-15-2005 07:02 PM ET (US)     Profile for Liteamorn  Send Email to Liteamorn     
Adding bus bars seems to be the best idea to me, your bound to add more electronics in the years to come and it sure makes it easy to install that way, you can make the + bus bar a fuse link if thats your pleasure but I use the inline fuses that come with the electronics.
DeepSouthWhaler posted 05-15-2005 09:25 PM ET (US)     Profile for DeepSouthWhaler    
I am going through the same situation on my Dauntless. I have one accessory switch but I need to add a VHF, chart plotter/sounder and eventually a stereo. I am running a
AWG-12 size wire from the accessory switch (positive) to a Blue Sea Systems terminal block/fuse panel. This panel is large enough to have 6 accessories. For the negative feed I am either going to tap into the ground for the switch panel on the dash or the ground for the gauges. I will then be able to run all of my accessories from the fuse panel and use the accessory switch as a main on/off for all the accessories. The entire boat's electrical system is run off of a dual battery system with a 1/2/Both/OFF switch.
The batteries and switch are located in the rear of the boat on the starboard side.
jimh posted 05-16-2005 08:57 AM ET (US)     Profile for jimh  Send Email to jimh     
The wire feeding the distribution block from the battery is only a 14-AWG conductor in a bundle of 8 other conductors. In such service a 14-AWG wire is only rated as low as 6-amperes of current, although this precise figure depends on what rating society is figuring the rating. This conductor is protected by a 30-ampere fuse, so the wire is being fused beyond its rated current capacity by some rating societies. The rating also depends on the insulation used on the wire. In the most generous rating I could find, a 14-AWG conductor is rated for 32-amperes maximum.

I don't have the ABYC rating book, and perhaps they do rate a 14-AWG wire in a boat to be good for 30-amperes. The length of that wire is short, so in any case the voltage drop across is should be small.

The 170 MONTAUK is sold with factory-installed VHF Marine radios. Where is the radio wired when installed at the factory? This would be a good guide for how to accomplish this.

MickP posted 05-16-2005 04:40 PM ET (US)     Profile for MickP  Send Email to MickP     
I appreciate all the great information, however would it be all right to hook my radio wires directly to those Johnny Ray terminal connectors that go to the positive and negative side of the battery there is a inline fuse on the hot feed to the radio, I realize forgetting to turn off the radio will drain the battery, This is a quick (temporary) hookup that seems to work, while I learn a bit more about the electrical side of the boat.
Thanks MP
Bulldog posted 05-16-2005 05:12 PM ET (US)     Profile for Bulldog  Send Email to Bulldog     
MP, yes do that! You can then plan what you want to do later, just don't add anything else without a plan , and don't keep adding stuff to that connection point. I'm an electrician and these guys know what they are talking about, but if you don't know what downstream is and which is positive and negative, just get that radio hooked up and then study a bit before adding the other equipment. The yellow wire to a stereo is usually the power to the memory circuit to the radio and needs to be maintained on, so that complicates the whole master and acc. switch thing even more. Enjoy your boat and keep asking questions..............Jack

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