Trawler Forum

Trawler Forum (https://www.trawlerforum.com/forums/)
-   General Discussion (https://www.trawlerforum.com/forums/s3/)
-   -   New to me 50, Steel full displacement, engine questions (https://www.trawlerforum.com/forums/s3/new-me-50-steel-full-displacement-engine-questions-30464.html)

Obie 03-05-2017 09:58 AM

Ok, I have another question for all you metal boat owners.
I am putting in a new ac panel today. I do not trust the old ac at all! So should I connect the earth ground (green) to the hull? My guess is no. I should also say I will be installing an isolation transformer in the very near future, but not today. But i will within a couple months.
Obie

Thank you

SlowGypsy 03-05-2017 11:12 AM

Common wisdom suggests that the green AC grounding wire on the boat should be:
a) NOT connected to the white neutral wire. These two are connected only at the shoreside power source, and at any onboard power supply, such as generator, inverter, or isolation transformer.
b) The green grounding wire should be connected to the battery negative, and therefore the boats bonding system, and, therefor, the hull itself, in the case of a steel boat. It may be connected to battery negative through a galvanic isolator, but this is not the best solution.

I would suggest you install the isolation transformer sooner, rather than later.

There is a need for much research on this topic, in my opinion. 'Though ABYC, Calder and other experts seem to agree on this grounding to batt. negative connection, it does scare me in terms of the potential for corrosion on a steel hull. There are seemingly knowledgable people out there who disagree.
I personally do not like the idea that my steel hull is in effect connected directly to the AC neutral return wire, which is a full current carrying conductor! (The white and green wires are connected at the main AC panel on shore)

I think you need to research it as much as possible. Once that isolation transformer is installed, I think the question is moot.

Jeffrey S 03-05-2017 01:35 PM

Quote:

Originally Posted by Obie (Post 530081)
Ok, I have another question for all you metal boat owners.

In all seriousness, don't do this yourself if you don't have an incredible understanding of all the issues. Hire a real, certified marine electrician and learn from them (someone who understands steel boats). Doing it wrong will create a serious life-and-death risk for you and your guests as well as do great potential damage to the integrity of the steel structure of the boat.

SlowGypsy 03-05-2017 01:44 PM

Agree, 100%! 👍

Obie 03-05-2017 11:06 PM

Well that's kinda funny, because the so called experts do not agree! The problem with connecting the green to the hull, and even the negative on the low voltage is galvonic corotion. If there is stray curints in the water they can use your hull to compleat the circuit. Back to the source. In exstream cases it could degrade you hull to the point of sinking in days, not months. It is a very serious. On the other side if you do not ground your hull and you have a short in an appliance, it could ground a person to the hull, causing a health risk.
A galvonic isolation transformer makes no true connection to the shore. It transfers power, (at a loss) through coils. Afestivly making its own power plant on your Vesel, using shore power as the generating source. So grounding your hull should isolate you from the shore. What I am conserved about with grounding you hull. Potintiolay you could open yourself up for galvonic corrosion from your own system and not the shore.
So I do not think it is as simple as your local boat electrician doing some electrical wiring for you. Many have never thought this past a fiberglass boat. Do not be fooled by some one that called them self an electrican, there are many levels. Slowgypsy has a great response.
Thank you
Please any one else, what have you done?
Obie

Obie 03-05-2017 11:22 PM

I once had a 34 foot Catalina. When it was being built a screw from a stansion penitrated a wire on the positive side of the low voltage system. On this boat all the through hulls well bonded to the neutral system.
Now when you would drop the ladder and go down it, as soon as you hit the water you would start to feel the tingle, no guess work you knew something was shocking you. That was abyc. On a metal boat with a gen set on that could have been beady!

SlowGypsy 03-06-2017 01:19 AM

Obie, I think that was Jeffreys point. We can agree that there are so-called electricians out there who don't fully understand the problem, and they are not familiar with the special situation a steel hull presents. He was suggesting that it would be better to hire a really good, qualified marine electrician, rather than venture into an area that even the "experts" do not all agree on.
You appear to understand that a properly installed isolation transformer protects both your boat and its' occupants, as well as swimmers in the water.

In my experience, the problem is finding such a qualified electrician. We find lots who think they know what they are doing, but there are gaps in their knowledge that could prove dangerous.
By the way, full disclosure, at the moment my green grounding wire is NOT connected to battery negative. (I have had some small corrosion issues that I suspected were connected to this issue, and I am still tracking it down).
I do regularly check my boat for current leakage, and I don't frequent marinas.
I also do not plug my boat into shore power much. All will be resolved (I hope!) with an isolation transformer!
Good luck with your electrical project!

Obie 03-06-2017 09:07 AM

I do get that. This should be such a hot topic(haha get it).if I had faith in one persons I would let them tackle it, I don't. I am hoping to get more people chiming in with what has worked for them. My aluminum boat did not have an isolation transformer in it. I did put one in, and it's green was not connected to the hull. However it's 12 volt negative was. It has been doing great. I hired the very best company in portland to install it. 2 hours after he started I came back to the boat to find him googling everything he could. 4 hours later he was done. I paid for 4 hours at $120 per for him to google and make 8 connections. WOW. I do not like to spend money that way.

FF 03-06-2017 12:40 PM

Why wait? The isolation transformer will solve the issue.

Obie 03-12-2017 09:05 AM

Ok I am hoping to fire off the Detroit 6-71 today. Actually it is a 1964 gray marine. I have put it mostly back together. There are 2 things still stumping me, please help if you can. Stump 1, the starter. It looks as if there are two large wire lugs on it. Not just 1 with the block being the ground. Do these starters not ground through the block, and if so which conection is ground?
Stump 2. Off the wet cooled exost there is one coolant fitting I can't figure out we're to plumb, looks like it might go to the aircompresor on the front of the motor. Dose this make sense. Would this be a water cooled aircompresore?
Any help would be great
Obie
I can post pics later when I get to boat.

O C Diver 03-12-2017 09:43 AM

Posting pictures increases the accuracy of our guesses.

Lots of different starters used on 6-71s in 70 years. Most compressors tied to diesel engines are either cooled through common lubricating oil or engine coolant. Never seen one with raw water cooling.

Ted

Ski in NC 03-12-2017 10:27 AM

Common for the starter to have two big lugs. One on solenoid is pos, one on back of actual starter motor is neg. Most do not use engine block as a neg conductor. In fact many higher end engines there is no connection between neg and engine block to avoid putting any current through the metal hull.

Can't comment on the manifold/compressor plumbing. There are 47,000 ways to plumb the cooling system on a detroit and I've seen about half of them. Lots of creative plumbing out there!!

Pics will help.

Do not attempt to spin that thing over until you have positive control of injector rack with rocker cover off.

Also bar engine over a couple turns before hitting the go button.

Obie 03-12-2017 11:31 AM

3 Attachment(s)
Here are the pics. The first one the starter you can see the 2 lugs. The second is the compressor and it is the pipe out the side, is that for coolant?
The third is the isolation transformer, yep I put it in

Obie 03-12-2017 11:47 AM

Ok I just spent some more time on it and I am convinced the rear lug is ground. And that the pipe on compressor is water.
I am moving forward, please interject if you have out her thoughts.
Thank you

O C Diver 03-12-2017 11:49 AM

Pretty sure the positive is the lug on top with the loose nut. I'm assuming the lug in the back is negative.

Where is the air intake on the compressor?

I don't know the wiring code on isolation transformers, but would assume you use GFI outlets still. Also, would recommend plastic outlet boxes, covers, and hardware wherever practical. You have enough rust to chase on a steel boat already.

Ted

O C Diver 03-12-2017 11:55 AM

Quote:

Originally Posted by Obie (Post 532426)
And that the pipe on compressor is water.
I am moving forward, please interject if you have out her thoughts.
Thank you

If it's water (coolant ), there would be 2 connections (in and out). Have you identified the other and where it's hooked up?

Ted

Ski in NC 03-12-2017 11:57 AM

The two lower hoses on comp, where do they go? That is a coolant cooled comp. Upper fitting should go to cooling system, somewhere. It needs very little flow.

FF 03-12-2017 12:09 PM

It is only a cotter pin and 4 bolts to lift off the rack that moves the injectors fuel control.

Lift it off and be sure all 6 will EASILY slide in and out the same amount. Fingertip pressure.

This will assure you have control of the engine speed.

You will not mess up the rack adjustments doing this.Then reassemble before starting.

After its running either getting Da Book, or having an experienced DD man adjust the valves and "run the rack" .

This takes a special timing pin to make the measurements properly.

Do you need a recommendation for a service manual to have on board?

Xsbank 03-12-2017 12:15 PM

What do you need a compressor for? Except for a horn, can't think of anything else?

Nightsky 03-12-2017 12:23 PM

Quote:

Originally Posted by Obie (Post 530307)
Well that's kinda funny, because the so called experts do not agree! The problem with connecting the green to the hull, and even the negative on the low voltage is galvonic corotion. If there is stray curints in the water they can use your hull to compleat the circuit. Back to the source. In exstream cases it could degrade you hull to the point of sinking in days, not months. It is a very serious. On the other side if you do not ground your hull and you have a short in an appliance, it could ground a person to the hull, causing a health risk.
A galvonic isolation transformer makes no true connection to the shore. It transfers power, (at a loss) through coils. Afestivly making its own power plant on your Vesel, using shore power as the generating source. So grounding your hull should isolate you from the shore. What I am conserved about with grounding you hull. Potintiolay you could open yourself up for galvonic corrosion from your own system and not the shore.
So I do not think it is as simple as your local boat electrician doing some electrical wiring for you. Many have never thought this past a fiberglass boat. Do not be fooled by some one that called them self an electrican, there are many levels. Slowgypsy has a great response.
Thank you
Please any one else, what have you done?
Obie

Rod Schiewe from Newport was considered the steel boat electrical guru for tuna boats (schiewe marine supply newport or). Been several years since I've been down there so not sure if Rod is still active or retired but well worth tracking him down if you can.


All times are GMT -5. The time now is 11:25 AM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012